Model Engine Maker

Engines => Your Own Design => Topic started by: steamer on September 06, 2021, 09:47:00 PM

Title: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 06, 2021, 09:47:00 PM
This is the beginning of a new build!   A 1/4 scale Porsche 917  180 degree V12    or Flat 12.

This engine was instrumental in the victories for Porsche at Leman in 1970.    This engine also would go on to dominate in the CANAM series in the early 70's in its turbo form.  However, this build will be of the engine in the Leman endurance racer format as shown below.

Specifics:

Bore:  0.845"  ( 21.5mm)
Stroke:  0.692"  ( 17.6mm)
Displacement:  76.7 CC
Air cooled
Engine block   2 piece split at the crank for a right and left half per the prototype.
DOHC with 2 valves per cylinder with 12 individual heads sharing a common cam box.
Gear driven camshafts as was prototypical, with a timing Vernier at each camshaft
Camshaft:    Individual hardened inlet and exhaust cams pinned to a common shaft driven by a gear as per prototype.
Ball bearing Crank with hardened throws
Plain connecting rod bearings of 6.7mm diameter.
Pressure Lube
Scavenged dry sump
Carbureted  ( Original was fuel injected)
Ignition will be via glow plug for initial running and debug. 
Dual Distributors
Fuel    E85 Gasoline with synthetic oil mix

I'll be following the prototype where ever possible.   The output shaft will be prototypical, and be gear driven off the center of the crank..   The cooling fan and the distributors will be driven from the top counter shaft also driven from the center of the crank.

Features where I will be departing from the prototype

Connecting rods will be 7075 T6 Aluminum, with bronze bearings ( the originals were Titanium with shell bearings)

The crankshaft will be for the sake of durability and reliability be a ball bearing built up crank.    As popularized by Shilling.  The crank throws will be hardened A2 tool steel.

The Oil Pump and Scavenge Pumps:
The oil pump and scavenge pump were driven by a pair of spur gears off the lower output shaft and were mounted directly to the engine block and fed oil to the engine with internal passages.   This is the proper thing to do on an endurance racer.  The best way to avoid a broken oil line is to not have oil lines in the first place!    However, the only way to access these pumps, is to split the case.    For the sake of maintenance simplicity, I've elected to mount the pumps off the front of the engine, directly driven by the output shaft.   This will allow easy removal of the pumps.   
The output of the oil pump will feed 6 nozzles via a cross drilled hole in the left engine block.  These nozzles will be aimed at each connecting rod pair.
Scavenge will be taken from the sump from two sump pickups connected vis cross drilled holes in the right engine block.

Now running some oil in the fuel is a common way to lubricate the bottom end on 4 stroke Model engines.   That would preclude the need for a oil pump and a scavenge pump....but all of that will get sorted out once it's running.

I've made a start with the rotating assemblies.    I'll post up my progress shortly.

Link to the Design Thread.      https://www.modelenginemaker.com/index.php/topic,6259.0.html

Dave

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on September 06, 2021, 10:24:31 PM
And so another epic build begins. I for one, will be following each and every step. In some ways I feel very close to this one. Maybe it's next on my list.

Dont forget to reference your readers back to the 917 design thread from time to time.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on September 06, 2021, 10:27:06 PM
Carton of fresh popcorn: check

Comfy chairs for me and shop elves: check

bibs to control drool: check

Ready! :popcornsmall:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on September 06, 2021, 10:32:40 PM
Did you notice the caption on the second to last photo "porsche-917-racer-could-be-yours-for-a-cool-20-million.jpg ".

Now we can see why Dave is building his own, rather than buying

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 06, 2021, 10:40:43 PM
And so another epic build begins. I for one, will be following each and every step. In some ways I feel very close to this one. Maybe it's next on my list.

Dont forget to reference your readers back to the 917 design thread from time to time.

Mike

I can only imagine it's because you and I have been talking about the design of it for 5 years!! :cheers:

Life certainly got in the way of this one....My daughter's cancer....twice!.....the surgical reconstruction of my right quadricep, and a global pandemic!......  There!   that's three!  NO MORE.

 8)

Dave


Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 06, 2021, 10:42:18 PM
Did you notice the caption on the second to last photo "porsche-917-racer-could-be-yours-for-a-cool-20-million.jpg ".

Now we can see why Dave is building his own, rather than buying

Mike

And it's only affordable because it's only the engine...and it's 25 percent full size!!! :DrinkPint:

oh and one other thing....I pay the guy building it in beer....when he's not doing other things.....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 06, 2021, 11:03:53 PM
OK so currently I'm rejiggering the program to cut multiple parts by order of tools

There are 6 or so tool changes per part, if I do one part at a time, and I have 5 more parts that 30 tool changes...but if I cut more than one at a time....it's only 6 tool changes...and I can do something else in between....like crank pins.....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Johnmcc69 on September 06, 2021, 11:26:19 PM
Woo Hoo! Here comes the chips!
 Glad that everything's coming together Dave, it's going to be a really great build to follow!
 :popcornsmall:
 :cheers:

 John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 07, 2021, 12:05:38 AM
Thanks for coming along John!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 07, 2021, 12:44:24 AM
OK   8 tool changes per piece....or 8 total for 3 parts......

Just need to make a new base fixture, I think 3 at a time is a good place to stop...it's a 1.5 hour process for three


Oh and a little eye candy......a print and that print superimposed on the CAD model

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 07, 2021, 01:19:50 AM
And some more views of the CAD assembly model

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Don1966 on September 07, 2021, 02:35:07 AM
Ok Dave we are with you and want to see the chips flying …….LOL…..



 :cheers:
Don
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: petertha on September 07, 2021, 03:09:40 AM
Here we go!
Maybe you spoke to this is the design workup but what materials were used in FS engine for the various (I'll loosely call them composite / molded thermoplastic) components. They all have different color amber shades, perhaps heat aging affecting them differently? Or maybe Kevlar used back then? The fan shroud has a hint of fabric so presume its a composite layup vs molded? Will you similarly miniaturize these?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Art K on September 07, 2021, 03:28:43 AM
Dave,
This should be a good build I'll be following along, and try to keep up.
Art
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on September 07, 2021, 03:32:25 AM
Hey guys, pass the popcorn, I have a front row seat

 :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 09, 2021, 12:55:45 AM
Here we go!
Maybe you spoke to this is the design workup but what materials were used in FS engine for the various (I'll loosely call them composite / molded thermoplastic) components. They all have different color amber shades, perhaps heat aging affecting them differently? Or maybe Kevlar used back then? The fan shroud has a hint of fabric so presume its a composite layup vs molded? Will you similarly miniaturize these?

Honestly....I haven't gotten that far yet....I have looked at those parts and honestly I think they are Kevlar/polyester resin layups.    I think I will probably 3D print some of these parts...

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on September 09, 2021, 11:29:26 AM
Here we go!
Maybe you spoke to this is the design workup but what materials were used in FS engine for the various (I'll loosely call them composite / molded thermoplastic) components. They all have different color amber shades, perhaps heat aging affecting them differently? Or maybe Kevlar used back then? The fan shroud has a hint of fabric so presume its a composite layup vs molded? Will you similarly miniaturize these?

Honestly....I haven't gotten that far yet....I have looked at those parts and honestly I think they are Kevlar/polyester resin layups.    I think I will probably 3D print some of these parts...

Dave

Hi Dave and perertha,

I think you will find that the fan, the shroud and the injection trumpet decks were dough moulded using the DMC process, rather than a layup. DMC (Dough Moulding Compound) was a popular material for aerospace products in the 1970's 1980's. The DMC is an uncured dough-like thermoset compound, made up from either epoxy or polyester resins with a high proportion of chopped E glass fibre and other fillers.

The DMC process requires expensive heated metal moulds and some form of a mechanical or hydraulic press to close the mould. Similar in some ways to die casting moulds.

A measured amount of uncured dough moulding compound is rolled flat and placed into the heated female mould. The heated male side of the mould is closed, under pressure, forcing the dough molding compound into the mould cavities. Heat from the mould initially softens the dough molding compound so that it flows into every part of the mould very accurately. The heat then cures the compound.

The resulting material is both strong and light with the characteristic translucent amber colouring, you see on the 917 engine. The fibres are usually visible within the resin. The amber coulour seems to darken and become more opaque with age.

Sounds like a 3D print is the way to go. It would be nice to find a translucent amber printing filament to complete the illusion

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 10, 2021, 12:28:00 AM
Here we go!
Maybe you spoke to this is the design workup but what materials were used in FS engine for the various (I'll loosely call them composite / molded thermoplastic) components. They all have different color amber shades, perhaps heat aging affecting them differently? Or maybe Kevlar used back then? The fan shroud has a hint of fabric so presume its a composite layup vs molded? Will you similarly miniaturize these?

Honestly....I haven't gotten that far yet....I have looked at those parts and honestly I think they are Kevlar/polyester resin layups.    I think I will probably 3D print some of these parts...

Dave

Hi Dave and perertha,

I think you will find that the fan, the shroud and the injection trumpet decks were dough moulded using the DMC process, rather than a layup. DMC (Dough Moulding Compound) was a popular material for aerospace products in the 1970's 1980's. The DMC is an uncured dough-like thermoset compound, made up from either epoxy or polyester resins with a high proportion of chopped E glass fibre and other fillers.

The DMC process requires expensive heated metal moulds and some form of a mechanical or hydraulic press to close the mould. Similar in some ways to die casting moulds.

A measured amount of uncured dough moulding compound is rolled flat and placed into the heated female mould. The heated male side of the mould is closed, under pressure, forcing the dough molding compound into the mould cavities. Heat from the mould initially softens the dough molding compound so that it flows into every part of the mould very accurately. The heat then cures the compound.

The resulting material is both strong and light with the characteristic translucent amber colouring, you see on the 917 engine. The fibres are usually visible within the resin. The amber coulour seems to darken and become more opaque with age.

Sounds like a 3D print is the way to go. It would be nice to find a translucent amber printing filament to complete the illusion

Mike

Thanks for that Mike....this pesky work thing slows down my response!....That's an interesting note on the DMC process that I did not know about.   As far as 3D printing, I'm certainly at the right place to find a substitute material to replicate that.    I have a few materials in mind that I could use, but I'm also aware that not everyone has access  to those materials, so I may come up with something more readily available......I think I have some time to think that one over. 8)

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Art K on September 10, 2021, 09:06:16 PM
Mike,
Thanks for the info about DMC. It's above my pay grade I'm sure.
Art
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on September 10, 2021, 09:39:12 PM
DMC moulding fell out of favor when carbon fibre pre-preg became widely available.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 12, 2021, 01:42:16 AM
Ok...I got some time in the shop finally   More crank disk "B"s and I cut the crank pins.    The  pins need to be drilled and finished to length

When I inspected my first crank disk, I found it was out of spec, so I'll need to crank out 1 more tomorrow.

progress!!
 

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on September 12, 2021, 10:59:01 AM
More nice bits :ThumbsUp: :ThumbsUp:

Even with the best CNC machines, there can be slight tolerance differences between otherwise identical components. For critical components, like this built-up crankshaft, it can pay to make an additional one or two. You can then chose the very best, the cream of the cream,  for the final assembly.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: ozzie46 on September 12, 2021, 12:10:56 PM
Ok...I got some time in the shop finally   More crank disk "B"s and I cut the crank pins.    The  pins need to be drilled and finished to length

When I inspected my first crank disk, I found it was out of spec, so I'll need to crank out 1 more tomorrow.

progress!!
 

Just don't get cranky about it. :facepalm:

Ron
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 12, 2021, 12:31:25 PM
Yup  made 8   need 6    I have another blank and it's still set up..

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on September 12, 2021, 01:13:54 PM
Yup  made 8   need 6    I have another blank and it's still set up..

Dave

Need 6?? I guess that's 6 side A and 6 more side B

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 12, 2021, 02:04:03 PM
There are 4 B sections   and 2 A sections

Each A and B section has a finished side and a unfinished side  ( bearing diameter)

One side is finished in that the ball bearing diameter and mounting face are machined complete prior to assembly


The other unfinished side has the ball bearing diameter and face machined AFTER the section has been assembled to the crank pin  to guarantee concentricity

It's How Shilling did it actually.

The area in blue is finish machined after the 3 parts are put together either with loctite or just the press fit

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on September 12, 2021, 02:27:17 PM
Glad to see you underway with this one  :) I will be following along  :wine1: :wine1:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on September 12, 2021, 06:52:46 PM
I'm following along, Dave, but I don't have much to add.

Other than to say, "that is one complex crankshaft!  Wow!"    :popcorn:

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 12, 2021, 11:40:16 PM
Well....it's no Briggs and Stratton!.....I started with what I think is the most difficult part of this build.   The Crankshaft.    As the power from this engine is taken from the center by way of a big gear, and a 8 main ball bearing crankshaft.....it's a doozy!...I figured if i could build this....I can build it!

I'm putting together a post from today's effort....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 13, 2021, 01:13:32 AM
Made more cranks today, and all the crankpins.  The Crankpins are A2 tool steel.   The will be hardened.   The crank webs are 1144SP.     To test the press fit I made up a extra pin and cheek and pressed them together  ( .002" press fit") using some never seize as a lubricant.   It worked perfectly!   So I'll just keep going this week and see how many I can get done.   I need to order some more 1144SP to finish off the parts for the crank, including the central gear.  #2 and #4 32 DP cutters and a arbor.....lots of tool making this week I think.    I'm having fun with it thou.      I was able to save that oversize crankweb, so I have my 4 and they all meet spec.

Progress!

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on September 13, 2021, 03:19:31 AM
Looking great! I can hear the satisfaction loud and clear in your post.  :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 15, 2021, 12:32:15 AM
Ok  had an epiphany, and it resulted in reduced set up and machine time...light dawns over marble head...anyway I'll be finished with half the crank webs tonight....and then I can start the rest.  I'll order gear cutters tomorrow.  32Dp and 48 Dp    14.5 degree PA  and the rest of the stress proof.   I also ordered some ttstool holder blanks to make cutter arbors from.    As cheap as the steel id make them out of.  Starting to get some momentum here.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 15, 2021, 02:59:26 AM
A cranks done with a spare   In the middle of making the holding fixture for the Bs.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on September 15, 2021, 03:40:12 AM
What was the epiphany?  Pictures!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 15, 2021, 05:23:24 AM
 :lolb:  Instead of having a finished and unfinished A and B, I changed the assembly to a finished A side and a unfinished B side.  That means 2 set ups instead of 4 set ups.....so significant..

My biggest challenge this evening was ME!    Did some dumb things and broke tools....but I didn't lose parts! so I got there eventually!
I need to arrange to have the crankpins hardened....

Finished A sides on the left.   Unfinished B sides on the right


Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on September 15, 2021, 08:47:42 PM
Lots of parts !  I assume you have some type of assembly jig planned to keep everything square?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 16, 2021, 12:59:36 AM
Lots of parts !  I assume you have some type of assembly jig planned to keep everything square?

Thanks for looking in Craig

Yes    There will be 2.   One to press the B side onto the assembly, to keep is close to aligned, and a second one to hold the A side while I machine the bearing diameters on the B side to size and concentric to the A side.

After that.   It's all about stringing all the sections together into a single crankshaft just like stringing together beads.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 16, 2021, 01:54:00 AM
I don't think I've explained how this crank gets made very well, Shilling was quite clever!    His design allowed for some very high power outputs, with a fairly simple crank design.   It requires careful work, but it's doable

Hi approach was to create a ball bearing crank via many small pieces     If allows for large ball bearing mains, and also can provide for a ball or roller bearing connecting rod bearing as well.    If you've ever been into the bottom end of a modern 2 stroke or even 4 stroke motorcycle engine, you have seen this construction before.

So what I'm doing, is creating 2 crank webs, and a crank pin.   The A side has M4 threaded holes, while the B side has M4 clearance holes
The crank pin fits with a interference fit.   Seems simple right?

But how to you make sure that the two bearing diameters are concentric?   And it NEEEDS to be concentric!
There are 8 main bearings on this crankshaft,

One way that Shilling did it was to machine one side complete, assemble the 3 parts, and then FINISH machine the second side using the finished side as a datum both radially and axially.

Rinse and repeat 6 times.....plus a gear....and some end caps....and you have a 917 crankshaft

It's slow going as there are quite a few parts to make, but it seems to be coming together quite nicely.   I'm still torn as to finishing the second side in the lathe, with a fixture, or in the mill with some soft jaws to hang on to it.      but I'll figure that out when I get there.     

The OD and FACE in blue below are the two surfaces that get finish machined after assembly to assure concentricity....I've left material on the second web specifically for this purpose.

I am going with ball bearing mains 32 x 25 x 4, and bronze bearings on hard pins for the rod bearings.   Simple, and hopefully durable.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on September 16, 2021, 02:00:03 AM
Thanks. That does help to clarify what you're up to. And what you're up against! :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 16, 2021, 02:04:01 AM
Thanks Ron,

I think it's the best way forward.   Making that crank any other way would be daunting!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Art K on September 17, 2021, 01:31:52 AM
Dave,
I have been following along just not saying much/anything. I do have one thought though.
Quote
Making that crank any other way would be daunting!
As if doing it this way isn't daunting!
Art
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 17, 2021, 10:57:44 AM
Well   you can do (1) 6 throw  crank...or (6)  1 throw cranks....like I said if I can.make this crank...I can make the engine.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 17, 2021, 11:45:07 AM
Additionally...cutting the center gear on a solid crank would be tough without a gear hob.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 19, 2021, 07:44:20 PM
B sides underway!   I think The program is good now....now to run 6 good ones

Plug gage fits just a scouch tight, but alright
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 20, 2021, 01:13:32 AM
Ok   Progress!     Other than 18 holes to tap M4, and general deburring, the crankwebs are done with spares.!   The crankpins are also done with spares and I'm setting up now to get them heat-treated.   Lot of work there!....next is assembly fixtures, and gear cutting.  The 917 engine took power from a gear at the center of the crank.   I have some cutters coming.....fun  challenging project!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on September 20, 2021, 09:39:02 PM
Right on! I guess once everything is assembled you will know if you are good?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 21, 2021, 03:56:19 AM
Hey Bubba!    thanks for dropping by.

Right on! I guess once everything is assembled you will know if you are good?

Almost!!!   

In the first photo below....
the crank cheeks to the left are finished....

The crank cheeks to the right have the bearing diameters left large

Once the crank pins are hardened,  they will be installed in all the crank cheeks to the left..

THEN....all the right cheeks will be pressed on and oriented to match the left ones as close as possible.

See the second photo

Next...the semi finished crank is mounted in lathe fixture.    the fixture locates the left crank directly on center of the lathe.

Then....we finish turn the bearing diameter of the right hand crank disk  IN SITU, which results in two concentric diameters!

Then I'll bolt all these together and we have a crank!

Dave

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on September 21, 2021, 03:59:24 AM
Quote
Then I'll bolt all these together and we have a crank!


you make it sound so easy!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 22, 2021, 12:07:08 AM
Quote
Then I'll bolt all these together and we have a crank!


you make it sound so easy!

It's labor intensive    YES.   Particularly difficult?    NO  I don't think it is!!!!

All these parts could have been done on a Sherline manual lathe and mill.  Is there a lot of parts?   Sure!   But it spreads the risk out.    Imagine cutting a 6 throw 7 main bearing  crank with a gear in the middle in a home shop from the solid on a Sherline or any other lathe for that matter!    This solution really helps make building this engine feasible.   The crank pins are precision ground A2 round stock. Right out of McMaster!
I part to length, face the ends and drill a hole through them.     Harden and polish the ends and they're done.   you have 6 crank pins all within 8 microns of each other....Thank you Mcmaster Carr!


The crank disks are fussy in three dimensions.   But it's simple turning and boring, and the way the crank is built up, you get several chances to correct errors as you go.  Most of the crank dimensions are +/- .005" which most can hold without too much difficulty.   the rest can be jig positioned

The assembly will be about some assembly fixtures and an arbor press.   Most here have the press, and can make simple fixtures...which if you're going to be making engines, you better get used to it....you make lots of fixtures!!!!!

No I don't think it's that bad....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 25, 2021, 02:05:09 PM
Gear cutters and arbors are here!!! :whoohoo:

I'll post up what I get up to,    once I can cut the 3 primary gears, and get the pins hardened at Cletus's Heat treat Haven.....I can get on with the rods perhaps....

Gonna go where I see fun to do next.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on September 25, 2021, 05:32:56 PM
Dave, it's always fun when new tools arrive!  :LickLips:

Can't wait to see what you do next!  :popcorn: :popcorn:

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 25, 2021, 07:05:49 PM
Hey Kim

Thanks for following along.   Today's exercise will be mostly tool making and I may just post it to the tools section till I'm cutting-edge gears...

Thanks again for your interest..someone is reading it.     :ThumbsUp::ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on September 25, 2021, 09:08:36 PM
Were all reading it!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on September 26, 2021, 12:31:24 AM
Hey :cartwheel: I’m here.  Just stepped out to refresh the popcorn. :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on September 26, 2021, 02:05:44 AM
I never miss an episode.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 26, 2021, 03:15:54 AM
Ok   I really wanted to cut some gears for the 917 model  Got a Tormach arbor blank, got the gear cutters..   made the arbor from the blank.  Needed  1/2-20 tap..my two taps are dull, ok I'll single point them on the lathe.   Don't have a bolt with that tread..ok I'll go to the hardware store in the morning...let's get the gear blanks ready!    I'm out of material!!!!....sigh    :zap: :hammerbash: :Doh:....I'll get on the conrods tomorrow, and send the crank pins out to Cletus for heat treat...... :facepalm2: :wine1:
I may salvage something from this weekend.....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 26, 2021, 03:39:08 AM
OK  conrods.    The conrods on the prototype had nuts on the opposite face... ( see pictures one)

I'm going to try and duplicate that ....

It turns normal conrod build process on it's head a little...but shouldn't be too bad..   and yes    I DO have the material for the rods.!!! :facepalm:

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on September 26, 2021, 04:55:06 PM
Looking good  :ThumbsUp:  :ThumbsUp:  :wine1:

I've made some conrods that way round. It's the easier way (the only way??) to assemble and engine with a tunnel crankcase.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 26, 2021, 08:46:14 PM
Looking good  :ThumbsUp:  :ThumbsUp:  :wine1:

I've made some conrods that way round. It's the easier way (the only way??) to assemble and engine with a tunnel crankcase.

If you put all the rods on first, you can do it conventional
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on September 26, 2021, 09:49:16 PM
 :popcorn: :popcorn: :popcorn:   
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on September 27, 2021, 02:08:42 AM
Not a real productive weekend boys and girls..     i was able to make the arbor...check... I think I'll be fine with the gear cutter....god I hope so...

But NO MATERIAL>      I could have sworn I had a good foot of 1.5" 1144 sp......but I didn't ......

SO

I started on the con rods   I did the programing and it became apparent that the inverse screw location was a PITA!     So I flipped it as I was sure I could put this all together in the end.      Then I spent some time programing the conrods...and probably in pairs...which is where I left off ....mean while I've had a few doctor trips for my Daughter,   and the honey do...so It's been less than Crueby levels of progress.....but I did watch Lemans last night as I tried to get myself to sleep....good movie.....Love the main character!..... 8)

Cletus You'll be gettin a package shortly
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Johnmcc69 on September 28, 2021, 12:39:06 AM
 :ThumbsUp:
 :popcorn:

 John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 04, 2021, 03:20:23 AM
Connecting rod blanks going through Op 1.  Rod bolt holes. 
After that, then the cap is machined and parted off, and then bolted back on and finish machined.....1 in the machine and 11 more waiting their turn

Meanwhile, Cletus has started the heat treat process!    :whoohoo:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on October 04, 2021, 12:01:04 PM
It's probably just me .... but unless it's a test piece in the oven, I'm not getting it  :headscratch:

Looking forward to see how you hold those blanks while the CNC does it job  :cheers:

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 04, 2021, 03:24:29 PM
Yes Eric is testing a coupon part to verify the process for 57Rc.   

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jasonb on October 04, 2021, 04:04:57 PM
Good way to contour the caps and part them off in one go, avoids the bolt heads getting in the way if you do the contour on the whole part.

Will you tap in the CNC or don't you have that facility as I noticed you did not seem to do it for the crank webs.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Don1966 on October 04, 2021, 05:45:33 PM
Still with you Dave but I didn’t know Eric had a hardness tester….. :Love:



 :cheers:
Don
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 04, 2021, 08:24:28 PM
Good way to contour the caps and part them off in one go, avoids the bolt heads getting in the way if you do the contour on the whole part.

Will you tap in the CNC or don't you have that facility as I noticed you did not seem to do it for the crank webs.

Thanks Jason     my thoughts exactly.  Uses less material as well.

Holes are deep so a pecking pass is in order as well as doing the cobores first.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on October 04, 2021, 10:03:26 PM
Quote
I think you can see the stainless steel wallet used to prevent oxidiation of the item being heat treated.

Oh yes - that trick I've heard about before  :ThumbsUp:  - but as I have never hardened anything (on purpose) .... it didn't show up in my ready memorybank  :-[
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 05, 2021, 02:23:31 AM
"Will you tap in the CNC or don't you have that facility as I noticed you did not seem to do it for the crank webs.?


No I dont have rigid tapping capabilities, but 7075 T6 is pretty easy to tap.

The only down side to doing the cap this way is the drilled holes are deep and blind.   Gotta go easy  and let the chips come out.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on October 05, 2021, 11:13:37 AM
Dave - I'm sure that your CNC can do 'single point threading' and I would be rather surpriced if it isn't good at it .... but of course it requires the right Tool in the holder + G-Code.

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 05, 2021, 11:17:07 AM
Hi Mike    I use the canned peck full retract as well.   10 dia deep is still deep....but I just let it do its thing

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 05, 2021, 01:02:40 PM
My machine will thread mill, but as thread mills are expensive and I have taps...I'm going to keep it simple.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jasonb on October 05, 2021, 04:23:55 PM
I think Andrew who also has a Tormach uses a tapping head together with spiral flute or point taps and can run them at about 500rpm in aluminium at M2 or M3 sizes. Biggest advantage is that they will be nicely lined up under the spindle.

I usually just use F360s pecking option for deep holes
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 09, 2021, 03:57:10 PM
Whiskey has been hard at work doing some heat treating   crank pins in the furnace and quenching

Dave


PS   I think he has some splainin to do regarding that fly press!

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 09, 2021, 06:37:40 PM
Op 1 on the rods is done!!   Now I have 24 tapped holes and some rod bolts to make and we can profile and part off the caps and then finish the rod as an assembly
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on October 09, 2021, 07:06:58 PM
Whiskey has been hard at work doing some heat treating   crank pins in the furnace and quenching
(https://www.modelenginemaker.com/index.php?action=dlattach;topic=10504.0;attach=129230;image)
Dave
PS   I think he has some splainin to do regarding that fly press!

Do you know if Whiskey quenches the bits while they are still in the stainless steel wallet, or are they removed first?

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 09, 2021, 07:14:30 PM
Whiskey has been hard at work doing some heat treating   crank pins in the furnace and quenching
(https://www.modelenginemaker.com/index.php?action=dlattach;topic=10504.0;attach=129230;image)
Dave
PS   I think he has some splainin to do regarding that fly press!

Do you know if Whiskey quenches the bits while they are still in the stainless steel wallet, or are they removed first?

Mike

He kept the first on in the pouch.    60 to 65 Rc..before tempering......harder than woodpecker lips!    He's going to draw the temper now....A2 air hardening

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on October 09, 2021, 11:58:04 PM
Whiskey has been hard at work doing some heat treating   crank pins in the furnace and quenching
(https://www.modelenginemaker.com/index.php?action=dlattach;topic=10504.0;attach=129230;image)
Dave
PS   I think he has some splainin to do regarding that fly press!

Do you know if Whiskey quenches the bits while they are still in the stainless steel wallet, or are they removed first?

Mike

He kept the first on in the pouch.    60 to 65 Rc..before tempering......harder than woodpecker lips!    He's going to draw the temper now....A2 air hardening

Huh... that's interesting. I'd think it would be harder to cool the parts quickly if they're still wrapped in the stainless... Very interesting!
Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 10, 2021, 01:14:47 AM
Ok   7 rods done tonight  I'll do the others tomorrow as I run 3rd op.   While I was in the shop I mad a Joe Pieczynski small tap wrench its nothing more than what you see.  1 inch OD by .350 wide with a 0.144 hole thru and a 10-32 sets crew.   It works amazingly well for stuff from 4-40 down.   Got to give the new vice a workout too!....sweeeeeet!
Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on October 10, 2021, 06:16:15 AM
Very nice, Dave!  That is a cute little tap handle.  I may have to make one of those.  I really like my little red tap handle, but I can see having a round knob like that could be really nice :)

And excellent use of the Piper Vise!  Extra credit for that! :ThumbsUp:

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on October 10, 2021, 09:47:16 AM
To make the tools to make the parts  :)  :)  :)  :praise2:  :wine1:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 10, 2021, 02:45:15 PM
Very nice, Dave!  That is a cute little tap handle.  I may have to make one of those.  I really like my little red tap handle, but I can see having a round knob like that could be really nice :)

And excellent use of the Piper Vise!  Extra credit for that! :ThumbsUp:

Kim

Joe recommends wire brushing the knurls after as they can be a bit rough on the fingers....I would second that advise!   But I really like it..and I had the tool made and dusted in literally 10 minutes.....Going right into the tool box after.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 10, 2021, 02:51:00 PM
To make the tools to make the parts  :)  :)  :)  :praise2:  :wine1:

Thank you Roger......It is very satisfying ....to say nothing of making tools on a lathe I completely rebuilt from "boat anchor" status....nearly 10 years ago.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Don1966 on October 10, 2021, 04:49:50 PM
Putting that new vise to work I see buddy. ……… :Love:



 :cheers:
Don
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on October 10, 2021, 05:14:11 PM
Screw the tap holder! Where is the picture of the rods!! We want to see the good stuff! :Lol: :Lol:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 10, 2021, 05:32:04 PM
Screw the tap holder! Where is the picture of the rods!! We want to see the good stuff! :Lol: :Lol:

 :lolb:    Bubba want nice Rods!!!!!!    :lolb:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 10, 2021, 08:08:00 PM
OK Bubba!    3rd operation done on rods.   Profile the rod cap and part off, then finish cut the rod bolt face.  I need to work on part organization.   Especially when dealing with 12 each!   I had dozens or part sorter boxes while William and I were racing....do you think we'd have ONE I could use?    :ShakeHead:

I'll buy some more, but I cleared out the bottom 3 rows of drawers of this hardward sorter for the moment.   

In each is the embryonic rod, and the profiled, but not yet brought to thickness rod cap, with orientation marking  so the can go back together.    Now I looked at my screw assortment last week and said I have plenty of 4-40 grade 8 screws.........I was wrong.......they're M3's....... :facepalm: :hellno:

So Op 4 ,   bolting the parts back together and bringing to thickness will need to wait a couple of days.........
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on October 10, 2021, 08:36:05 PM
If you have a container store near by stop and get you some stackable divided trays. They are great for the long term projects and ones with a lot of tiny parts. Sound fimiliar?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 10, 2021, 08:46:41 PM
YUP    the RC community has brought it to a level of art form....because of all the traveling many do...it all needs to get packed tight

....but they're expensive...I like yours better for engine building

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on October 10, 2021, 08:57:43 PM
I've got a bunch of those boxes, great for all the small fastener sizes. I've found the cheapest good ones are at the fishing tackle aisles in the sporting goods stores - lots of variety of size combinations. I write in the fastener size with a fine tip permanant marker. Not very permanant, a little alcohol (not the drinking kind, that would be a waste! ) on a tissue cleans it off when I want to change it.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on October 10, 2021, 09:10:15 PM
Never thought of the fishing stuff aisle. I will have to check it out.


Dave those look expensive with all the individual little boxes. The trays I showed are not as good for travel but my project aint going nowhere. Much cheaper, but still not cheap.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 10, 2021, 09:13:42 PM
I'm down with that Steve....They're top quality and all, but man are they proud of them!....

When I bought my first 2 of those RSC boxes....the pair was $56.....

The price seems to have dropped a bit over the years

https://rsrc.biz/en/rsrc-products/1180-pama-box-56-compartments.html

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 10, 2021, 09:15:46 PM
Some honey do's today, and then back in the shop....I'm going to work out the cutting of the main drive gear so I have it when Eric is done with the crank pins

Should be interesting

Dave

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 10, 2021, 09:16:53 PM
Whiskey has been hard at work doing some heat treating   crank pins in the furnace and quenching
(https://www.modelenginemaker.com/index.php?action=dlattach;topic=10504.0;attach=129230;image)
Dave
PS   I think he has some splainin to do regarding that fly press!

Do you know if Whiskey quenches the bits while they are still in the stainless steel wallet, or are they removed first?

Mike


Correction!!      I spoke with Cletus, and he did take the pin out of the bag for quench.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on October 10, 2021, 11:30:35 PM
Dave,
Harbor Freight has several of those kinds of storage solutions for a pretty reasonable price.  The fishing tackle boxes Chriss is talking about are usually made by Plano.  HFs are not nearly as nice, but they're good enough (I've got a bunch of both) and they're less than half the price of the Plano.

They also have something kind of like your previous picture.  Again, I'm sure it's quite a step down in quality, but it's only $6, and I'm betting it would hold parts.
https://www.harborfreight.com/24-container-storage-box-90243.html (https://www.harborfreight.com/24-container-storage-box-90243.html)

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 10, 2021, 11:41:10 PM
Thanks Kim!!  I'll order some up!!!
Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on October 11, 2021, 12:13:14 AM
Bass Pro Shops/Cabellas (same company these days) have good ones too in store brand:
https://www.basspro.com/shop/en/utility-boxes#facet:&productBeginIndex:0&facetLimit:&orderBy:&pageView:grid&minPrice:&maxPrice:&pageSize:&
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: 90LX_Notch on October 11, 2021, 02:10:01 AM
I wouldn’t call that a Joe Pie tap holder.  I made one at least 5 years ago after seeing a post that Marv made.  I’d call it a Marv tap holder.


-Bob
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 17, 2021, 11:11:08 PM
OK   Some progress this week...no where near enough, but I've had to work the weekend, and late all last week, so it is what it is.

I have all the material I need for the Crankshaft and the connecting rods.    Cletus delivered my crank pins, right where I asked them to be at  52 Rc.  and as so tempted as I was , I've avoided pressing one in yet.   I need to lap and polish them first.

For the crank
I need an assembly fixture to align the second crank at least close to the first.   that may be made up with a 123 block...
I need to make a fixture to hold a crank section while I finish machine the B side crank.   
I need to machine the center drive gear.   I have the cutters and a cutter arbor.
I need to machine the crank end bell shaft sections....easy peasy...

Connecting rods
I need to bore them to size
I need to fixture them on the bores
I need to profile them to shape

Big end bearings.
I have the material....it should be straight forward.

I was able to get some organizers at Horror Fright...I bought them out!    Nice to have a place to put things and it's amazing how many parts I'm into already

I should have some time later in the week...and I'll take advantage of that.

Dave

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: tghs on October 18, 2021, 01:45:25 AM
I have found these boxes work well, the adjustable bins help a great deal..
https://www.homedepot.com/p/HDX-15-Compartment-Interlocking-Small-Parts-Organizer-in-Black-2-Pack-320034/204515485?source=shoppingads&locale=en-US&&mtc=Shopping-B-F_D25T-G-D25T-025_011_STORAGE_DEVI-Multi-NA-Feed-PLA-NA-NA-StorageDevices_SmartShopping&cm_mmc=Shopping-B-F_D25T-G-D25T-025_011_STORAGE_DEVI-Multi-NA-Feed-PLA-NA-NA-StorageDevices_SmartShopping-71700000081401733-58700006882766023-92700061894095921&gclid=CjwKCAjwk6-LBhBZEiwAOUUDp97xjDDnMOKzQnEu3rPXnuQxPC0x3f3UzPv889pnneRPZW0bns2CQRoCKlYQAvD_BwE&gclsrc=aw.ds
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 23, 2021, 06:23:27 PM
Some progress photos!    I could not help but put one crank section together, and wow I was worried about nothing!   The procedure is thus.  Make a guide block so you can start to press the pin home squarely.   It's just a block with a close fitting hole that matches the crank pin.   Press the pin home into the A side crank, which is a finished part.  .  Take off the block and put aside.  Line up the raw machined crank side B and tap onto the crank pin lightly (.0015 to .002 press fit on a 7mm pin).  Set the finished side down and check the two crank disks for alignment with a square.  Tap the raw one around until it lines up on both crank disks.   Then press the second disk home to the appropriate crankpin inside width 0.520"....and it's on     next step is to machine the second web bearing diameter in situ to fit the 25 mm bore ball bearing and to appropriate overall length.  I'll need to make a fixture to hold side A concentric while I turn side B.    Not that hard at all Mike.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on October 23, 2021, 06:27:48 PM
Nice!
 :popcorn: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on October 23, 2021, 06:32:02 PM
Must feel good to get your process verified by the first good part!   :popcorn: :popcorn:

Dave, how are you guaranteeing the 0.520" spacing?  Do you have a gauge block or something that you're using to set between them as you do the press-fit?

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on October 23, 2021, 06:51:52 PM
Great to see the progress.  Sometimes the 'hard' stuff isn't as hard when you get into it.  Looks great Dave.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 23, 2021, 06:53:16 PM
Must feel good to get your process verified by the first good part!   :popcorn: :popcorn:

Dave, how are you guaranteeing the 0.520" spacing?  Do you have a gauge block or something that you're using to set between them as you do the press-fit?

Kim

I bumped it in with the mill vise, but I'm going to use an adjustable parallel that I can collapse and then reset.   I have .005" on both sides of each con rod bearing so I have some room for error, but I'm striving for on the nose.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 23, 2021, 07:06:17 PM
Great to see the progress.  Sometimes the 'hard' stuff isn't as hard when you get into it.  Looks great Dave.

YUP!!!   So now I'm wondering about the stuff I think is going to be easy!!!

Now coming this far, I'd say that .002" interference on a hardened pin in the 6-8 mm diameter range is no problem at all.   It hold very well!   With it pressed in 1/4 the way, it needed to be moved with a soft faced hammer, so pressed home it's not moving.   My engagement is 1 pin diameter deep. 

I used a 0.265" diameter crank pin as I can get graded reamers going up or down easily in the states.   Now over seas, 7 mm diameter may be a better choice, but check for reamers that are appropriately undersized ( 0.039 to 0.050 undersize) so that you get the press you need.    The pins were made from precision ground A2 tool steel, that aside from drilling through and parting to length, were finished diameter and +/- 8 microns..    It needed little other than hardening and polishing.   Lightly round and polish the ends with some 600 grit to ease the pin into the hole to start with.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: 90LX_Notch on October 23, 2021, 07:34:22 PM
Nice Dave!

-Bob
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on October 23, 2021, 08:07:09 PM
Great to see the first parts come together  :cheers:

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 24, 2021, 12:05:07 AM
I was able to get 3 more assemblies together and some photo's    I make myself a "Sledge" as at .06 insertion depth....you need it!

And a family shot.....lots of parts....

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on October 24, 2021, 05:36:09 AM
Great set of process pics, Dave.  Really helps me see how you're tackling this!

Nice box'o parts too!  :ThumbsUp:

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on October 24, 2021, 12:22:27 PM
Good stuff Dave!

Will there be a grub screw or some kind of pin to keep the disk from rotating on the pin?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 24, 2021, 01:17:29 PM
Good stuff Dave!

Will there be a grub screw or some kind of pin to keep the disk from rotating on the pin?

No   not required.    Once it's in the block it can't physically move.   

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on October 24, 2021, 01:21:16 PM
I was able to get 3 more assemblies together and some photo's    I make myself a "Sledge" as at .06 insertion depth....you need it!

And a family shot.....lots of parts....

The crankshaft looks to be coming together nicely.  :ThumbsUp: :ThumbsUp:

That was a neat trick to use the mill vice to press the pins home. A mill vice will keep everything square and parallel and you should be able to apply the force with much more control than with a fly press. I also like the depth stop ideas to set the length and gaps. What I could not see was how you aligned the two discs before you pressed the second disc home.

Cheers

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 24, 2021, 02:33:35 PM
I was able to get 3 more assemblies together and some photo's    I make myself a "Sledge" as at .06 insertion depth....you need it!

And a family shot.....lots of parts....

The crankshaft looks to be coming together nicely.  :ThumbsUp: :ThumbsUp:

That was a neat trick to use the mill vice to press the pins home. A mill vice will keep everything square and parallel and you should be able to apply the force with much more control than with a fly press. I also like the depth stop ideas to set the length and gaps. What I could not see was how you aligned the two discs before you pressed the second disc home.

Cheers

Mike

Hi Mike,

After you press the first side home, line up the second side by eye, and using the vise, press the pin about .06" deep using the vise.    Then I set the "A" side down on the flat tail of the vise, and brought a square up against it.    In this case, it was the sharp edge of a precision ground V block which is known square.   

If the two crank cheeks are aligned correctly, then both crank cheeks should touch the square at at all positions checked around the crank module assembly.    If it is not, I bring the assembly over  to my vise, and "bump" the "B" side web around rotationally around the partially installed crank pin until is passes this test.   It typically takes 3 or 4 or even more tries to get it acceptably aligned.

It doesn't need to be perfect, as the "B" side will be machined next using the finished "A" side as datum.   

Once acceptably aligned, I return the assembly to the vise, install the pre-set width stop, and press the "B" side home.   Once there ....it's not moving.

The "B" side has 0.04" on diameter, and .03" on length  to come off to get to finish dimension.   Any error left from the press fit assembly operation is removed by machining.

Dave


Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on October 24, 2021, 02:52:33 PM
Hi Dave,

Thanks. I can see how that works. Neat and simple, I had anticipated something more complex

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 24, 2021, 03:01:55 PM
Hi Dave,

Thanks. I can see how that works. Neat and simple, I had anticipated something more complex

Mike

Thanks Mike.....

Honestly....It's the way to go.   It gives you a chance to correct errors along the way and different steps of the process.   So far I am very happy with the Schilling approach, and can recommend it.   Schilling recommends .001" press fit....but I found with a hollow crank pin, you can go up to .002" which gives you some leeway on the pins and bored hole tolerances.   And I mean it....once that pin is in....It's not moving...I estimate it would take a 2 pound ball peen hammer to move a crank web once it's pressed home.....it's very secure....

Pins are .265 OD x .156 ID A2 hardened tool steel with 1144 SP crank webs with a .0015 - .002" press fit.

Crank pin is hardened to 50-55 Rc.

Build a few extras to make up a trial assembly to sort out doing this in YOUR shop..  You will learn alot.

Dave



Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on October 24, 2021, 03:14:35 PM

.........Build a few extras to make up a trial assembly to sort out doing this in YOUR shop..  You will learn alot.

Dave

Thanks Dave,

It is all too easy to overthink the problem. It's only when you have some hardware to play with, that you understand

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 24, 2021, 03:27:04 PM

.........Build a few extras to make up a trial assembly to sort out doing this in YOUR shop..  You will learn alot.

Dave

Thanks Dave,

It is all to easy to overthink the problem. It's only when you have some hardware to play with, that you understand

Mike

Aint that the truth!!!!

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 24, 2021, 10:49:43 PM
Making the lathe fixture to finish the crank cheek.....material was left on the bearing OD and face for this operation.   Needs some tapped holes.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 31, 2021, 09:42:39 PM
Much to do this weekend, including some quality time with my son.   Tonight I spent some time roughing out the crankshaft gear blank although it appears the belt on my lathe needs to be replaced...    :hammerbash:

The engine e on the Porsche 917 took its power from the center of the crankshaft.   My model will be the same.  and as this will be a 8 bearing ball bearing crankshaft, run out is critical, so I also spent some time checking the collets for my lathe and my dividing head for minimum runout.    I've gotten it down to .0005" on the dividing head and about .0003" on the lathe.....I'll be using a 1/2" collet   (3C in the lathe and #7 BS in the dividing head) so the blank has a 1/2" shank.

I'll use that for the "A" side of the gear (24 mm bearing diameter) and the gear teeth them selves,  then I'll part it and finish the opposite side in "The Fixture"!

Now "The Fixture" is a simple piece of stock with a 24mm socket that all the crank assemblies, the end crank shafts, and the center gear will be mounted to, to finish the "B" side bearing diameter concentric to the "A" side bearing diameter.    It's a simple part, and it's machined in situ.   Once its ready for use it CAN NOT come out of the lathe until all the parts are finished...so all the crank pieces need to be done first.

It appears I've worn out the serpentine belt on Samantha Bell    It has been nearly 10 years......

Dave

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on October 31, 2021, 10:23:03 PM
Funny - it looks like the crankshaft itself, is a lot stronger than the "Torsion Bar" they used for the Power Output Shaft .... but that might even be done on purpose  :thinking:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 31, 2021, 10:37:47 PM
I wouldn't be suprised admiral.     In the can am version of 1800 HP,  the output shaft was 25mm diameter and of titanium.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 31, 2021, 11:03:24 PM
Winding up the output shaft is much better than winding up the crank and messing up engine timing ect
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Don1966 on November 01, 2021, 04:29:03 AM
Looks great Dave!…… :Love:



 :cheers:
Don
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on November 01, 2021, 01:30:14 PM
Very nice Dave. :popcorn:

I noticed the crankshaft is symetric about the center with the exception of the two outside throws.  In sure there is a reason but it currently escapes me.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 01, 2021, 02:24:38 PM
Outside throws are symmetric   throws are all at 120 degrees

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on November 01, 2021, 02:34:55 PM
Outside throws are symmetric   throws are all at 120 degrees

Dave
In the CAD drawing picture, the throws from the middle to the right appear to spiral 120 degrees in one direction, but on the left they go one direction then back to match the center one? Why is that one on the far left the same as the center throws?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 01, 2021, 02:49:08 PM
The CAD image is wrong...
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on November 05, 2021, 07:56:42 PM
There's a lot of interesting stuff going on here  :praise2:  :praise2:  :wine1:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 05, 2021, 11:22:42 PM
Yes there is Roger!   too many hours at work ....but I hope to get some shop time in this weekend

I fixed the assembly model of the crank

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on November 05, 2021, 11:30:16 PM
Impressive design - amazing to make at model scale!

 :popcorn: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 06, 2021, 11:49:53 PM
Impressive design - amazing to make at model scale!

 :popcorn: :popcorn: :popcorn:

Thanks Chris!    I have made a set of gear blanks that include the crank gear, the output shaft gear and the distributor/fan drive gear.   They are all 32 tooth 32DP gears, so just as well to cut them all in the same set up.
 
I made a TTS cutter holder for the gear cutter, and tomorrow I'll set up and cut them!   
today I spent some time doing fall clean up and organization.  I moved the old lathe bench out of the shop, and put my table saw in the basement for the winter.   Took the A/C out of the window and turned on the heat!   It was 24 F outside this morning!!!


Oh and I fixed the SB.   I tried tightening the belt, and that fixed it for now........I suspect I'll need to change that belt before too long

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 07, 2021, 07:07:09 PM
Im set up....has anybody climb milled with a gear cutter before?   

Don't mind saying this is spooking me ....I've cut a lot of gears conventionally....never climb....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on November 07, 2021, 07:24:10 PM
Allways climb mill gears
Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 07, 2021, 07:29:45 PM
Thanks Mike!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on November 07, 2021, 07:34:35 PM
One fulĺ depth pass then a spring pass.
Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 07, 2021, 07:36:09 PM
One fulĺ depth pass then a spring pass.
Mike


That's the plan
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 07, 2021, 07:37:23 PM
Gonna put a footstock on it though

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on November 07, 2021, 09:15:04 PM
Gonna put a footstock on it though

Tailstock???
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: kuhncw on November 07, 2021, 10:30:15 PM
Allways climb mill gears
Mike

Mike, what is the reason for climb milling gears vs conventional milling?

Chuck
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 08, 2021, 12:11:45 AM
Gonna put a footstock on it though

Tailstock???

Cylindrical Grinders AND Dividing heads it's called a footstock

On a lathe it's a tailstock

I didn't name them.......

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 08, 2021, 12:25:58 AM
OK    good evening  it'

I was able to cut the teeth....not without incident, but I guess I'm not surprised as it's the first time cutting gears on a CNC mill.

I've cut many gears on manual mills , like my #12 Van Norman mill....and it was ALWAYs  conventional cut always towards the dividing head.   That is not an option with my software on a CNC mill as far as I can tell.   But no matter it climb cut quite nicely.   CNC is always better as climb milling.....it's just not my experience ....so I got nervous....but there was no need.

300 rpm was just fine, and I think with the mist coolant that I could safely go to 400 without any problems
What I did wrong, was set the center of the cutter on center with the work piece quite precisely....which is what I would do with my Van Norman or my F1....there was the rub!    Zero on the program is the bottom edge of the cutter, not the center...so it cut low by half a cutter thickness....  Once I got that sorted out I started making decent teeth!   but of course the damage was done.

The mill doesn't have the snot to run at 3 inch/min at that speed....2 in/min is just fine.    I'm not surprised as the spindle will run happily at 10,000 rpm so as a belt drive machine, Im not at all surprised.    I can work with it, as the gears are small, and I don't suspect I'll need to cut anything of bigger DP than Mod 1 or 32 DP.

So I'll make up another blank and have at it....this week I think....we'll see what work brings to my desk...

I have a BS1 dividing head....I think a BS0 might be better given the table size....  I'll look into that

Thanks for following along......

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: john mills on November 08, 2021, 12:52:09 AM
climb milling is always better than conventional milling  but only on machines rigid enough and no backlash preloaded ball screws and the work must be held  to control the cut .  at apprentice school they had a good big heavy horizontal mill with back lash eliminator but
when they tried to show how it worked it picked up the vice and threw it over the end of the table it was a good big solid vice firmly held with 5/8" bolts so they put it all back making sure it was done up tight and tried again same thing so they didn't try again.whith good cnc machines with preloaded ball screws  and good spindles i always climbed mill unless the set up was likely to be a bit springy .
good you have the gear cutting working.
  john
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 08, 2021, 01:02:17 AM
YUP   35 years turning cranks and now slinging pixels!.......designed quite a few of them too....just never got a chance to run CNC myself till I got my mill....it's a bit of a learning curve...and you have to learn to trust the machine and change your work methods....

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 08, 2021, 01:19:53 AM
Case in point

https://www.modelenginemaker.com/index.php/topic,649.msg6073.html#msg6073

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: john mills on November 08, 2021, 08:09:04 AM
your little mill with high spindle speeds carbide end mills should love climb milling  when you start with larger end mills in cnc machines
plowing into tool steels is something to think about but it works and you quickly see it works i started more than 40 years ago but
i had to wonder on old machines that have long seen there best but never had any trouble i didn't climb mill holding tough steels in a indexing head and using larger cutters where the setup needs to be rigid .
John 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on November 08, 2021, 06:04:18 PM
YUP   35 years turning cranks and now slinging pixels!.......designed quite a few of them too....just never got a chance to run CNC myself till I got my mill....it's a bit of a learning curve...and you have to learn to trust the machine and change your work methods....

When you convert to the CNC way: you must trust your machine and trust the drawings.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 09, 2021, 12:57:41 AM
YUP   35 years turning cranks and now slinging pixels!.......designed quite a few of them too....just never got a chance to run CNC myself till I got my mill....it's a bit of a learning curve...and you have to learn to trust the machine and change your work methods....

When you convert to the CNC way: you must trust your machine and trust the drawings.

Mike
t
Yes you do!   I set the center of the cutter at the center of the gear.....of course the software set zero at the bottom face of the cutter set to cut the bottom face of the gear tooth slot.....so half a gear cutter thickness low....once I convinced myself that I set it on center....like 4 times....it dawned on marble head that the software wasn't reading my mind...    I say I sack the software!!!!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on November 09, 2021, 01:12:58 PM

I set the center of the cutter at the center of the gear.....of course the software set zero at the bottom face of the cutter set to cut the bottom face of the gear tooth slot.....so half a gear cutter thickness low....once I convinced myself that I set it on center....like 4 times....it dawned on marble head that the software wasn't reading my mind...    I say I sack the software!!!!

Dave

There is still a lot of merit in using less sophisticated CAM software than Fusion 360 and the like.  :killcomputer: 

OK, you may have to do more of the work, but the lower level of automation leaves you, rather than the software, in command of the process.


   I say I sack the software!!!!

Dave

Yep, I go along with that as you must also trust your software or have software you can trust

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 15, 2021, 01:25:08 AM
Good progress today!   First of three gears went great.   I'll cut some more this week .   I need 3 of this tooth count.

Dave

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on November 15, 2021, 01:56:18 AM
Looking great!  What is the black coating in the gear teeth?


 :popcorn: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 15, 2021, 02:13:26 AM
Just a shadow.no coating

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on November 15, 2021, 05:29:57 AM
Nice looking gear!  Is it going to stay this wide? Or get narrower before actual use?

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 15, 2021, 11:13:05 AM
Nice looking gear!  Is it going to stay this wide? Or get narrower before actual use?

Kim

Hi Kim.   Thanks for looking in!    No actually it will finish off looking like the picture below.   To physically cut the part, the blank needs to be 1" away from the face of the DH spindle...so at the moment it's a gear on a stick...
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on November 15, 2021, 12:37:16 PM
Good progress today!   First of three gears went great.   I'll cut some more this week .   I need 3 of this tooth count.

Dave

Another small step foreward

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 15, 2021, 12:51:07 PM
Good progress today!   First of three gears went great.   I'll cut some more this week .   I need 3 of this tooth count.

Dave

Another small step foreward

Mike

YUP   And with what's going on in my life.   well small steps is all I can do.  i'll endeavor to take them every week.

Dave

 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on November 15, 2021, 09:53:08 PM
Great to see progress Dave and a nice result  :ThumbsUp:

I would have said that only one of them ends up as a part of the crankshaft  :headscratch:

Are the two others idlers or for the Oil Pumps ?

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 15, 2021, 10:09:26 PM
Per


Power comes from the center of the crank
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on November 15, 2021, 10:14:55 PM
So this time my memory wasn't half bad  ;D  thank you Dave.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 15, 2021, 10:19:01 PM
So this time my memory wasn't half bad  ;D  thank you Dave.


 :headscratch:

No the output shaft is below the crank shaft...so that's the primary, and the output way shafts

The other gear is for the fan and the distributors.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on November 15, 2021, 10:34:31 PM
Very interesting arrangement on the output shaft!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on November 16, 2021, 11:54:40 AM
OK, I wasn't clear.

I understand it as, two of the gears you made, are for the Crank and the Output shaft (the red line) - they certainly appear to be same size ...?

I admit that I guess that the third will be slimmed down and placed on the last shaft in the picture .... so, all three mess with each other .... I know it's a dangerous assumption ....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Hugh Currin on November 16, 2021, 02:44:25 PM
Dave:

Great progress. Thanks for dragging us along.

For the "gear on a stick", did you consider making a "pinion shaft"? What I mean is cutting the gear section long enough to get all three gears from. More overhang but only cutting one long gear. Just curious.

The center take off on the crank makes sense to me. The torque is half on each side rather than pulling power from one end. The crank will see more cyclic loading than the final output shaft after the gear. Might explain why the final output isn't larger than the crank? Makes sense for a racing motor, but would probably be more expensive for production vehicles.

Thanks again.

No actually it will finish off looking like the picture below.   To physically cut the part, the blank needs to be 1" away from the face of the DH spindle...so at the moment it's a gear on a stick...
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 17, 2021, 01:12:38 AM
Hi Hugh,

The problem I have is that with the dividing head on my table, I lose some travel...to complicate it, I need to have the HS side of the gear at least 1" away from the spindle of the dividing head.   I run out of room to put the footstock/tailstock on the table...so I can't make the gear blank too long....so you end up with a gear on a stick ......Im going to build a sub table that lets me hang the HS way to the left over the table drive, that will let me get a footstock/tailstock on

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Hugh Currin on November 17, 2021, 04:43:56 AM
Dave:

Well, that answers that question. Does sound like you considered it though.

Nice progress.

Thanks.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Mike R on November 18, 2021, 03:20:21 AM
Dave,
Looks like good progress.  Are you creating specific code for each gear in Fusion (sorry if I missed it, skimmed through and if I read it I didn't register it).  I wrote a simple bit of G-code to conventional mill gears - edit the code with the # of teeth, gear width,  cutter diameter, cut depth, etc. and it does the rest.  Seeing Mikes comment on climb milling I may have to revisit and redo the code to climb mill.  regardless let me know if you want me to share it.  I wrote a DP version and a Module version and they seem to have worked out so far for me.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 18, 2021, 11:27:12 AM
Thanks Mike!    Unfortunately I don't currently have an A axis on my mill other than my old school dividing head....
I have a simple program that cuts a tooth full depth with a gear cutter and follows up with a "Dead pass"...and that completes the cycle
Index the head and hit cycle start...simple as that

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 21, 2021, 03:19:31 PM
No machining this week....had a spot of bother design wise that I missed, but I've got the solution well in hand....and I'll expound when It's sorted out.

Luckily I found it before I got into it!..

It's a risk you take on a new design....... :old:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on November 23, 2021, 08:23:47 PM
It's a risk you take on a new design....... :old:
Been there got the teeshirt and the cap  :toilet_claw:  ::)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on November 26, 2021, 05:41:28 PM
Can't recall one engine I designed where the design didn't change somewhat as the build progressed, either through errors in the design I uncovered along the way or just a better design discovered as I 'got there'.  To me, it's just part if the design/build process.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on November 26, 2021, 06:08:04 PM
Can't recall one engine I designed where the design didn't change somewhat as the build progressed, either through errors in the design I uncovered along the way or just a better design discovered as I 'got there'.  To me, it's just part if the design/build process.

Spot on Craig. I look upon the combined design/ build process is a creation process.

Dave will soon have it fixed and the engine design will be stronger than ever.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 26, 2021, 10:28:20 PM
Can't recall one engine I designed where the design didn't change somewhat as the build progressed, either through errors in the design I uncovered along the way or just a better design discovered as I 'got there'.  To me, it's just part if the design/build process.

Spot on Craig. I look upon the combined design/ build process is a creation process.

Dave will soon have it fixed and the engine design will be stronger than ever.

Mike

Yes it will!!!     I have to do "Work" work this week....including yesterday and today...but I'll roll back in shortly.   
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: JonC on December 02, 2021, 12:31:30 PM
Great work Dave.

Following along quietly in the background, learning all the way.

Jon
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 04, 2021, 04:47:50 PM
So I had a situation.     :toilet_claw:

I found that the 4mm bolts holding the crank together where going to break out into the root of the center gear on the  crank.    That WAS a 32 tooth 32 dp gear, to fix that, I changed the gear to a 35 tooth.   Doing  that increases the distance between the upper distributor/fan shaft and to the output shaft.   That changes the engine block ....and the gear centers to the cams.....lots of bad words were used......

I just didn't see it, as it was approximately flush....why didn't I see it?   well I modelled the holes in the crank at .386" from the center.....and had a senior moment when I modeled the gear and typed in .368.....a simple transposition.....but it was enough to not see it

OK...the good news.   I have not started machining the block!....so I took a divergence, and remodeled the block to correct this

Gear counts were  32/56  35/40    for a 2/1 reduction

NOW   

Gear count is 35/56  32/40   also for a 2/1 reduction

It required changing the centers of the gears in the gear towers, and a change in the block centerlines, but nothing else that I can see.   It also afforded me the ability to put in bigger bearings on the lay shafts.  So it worked out for the best going forward

Then I had to work for the last 14 days straight including the holiday......so nothing has happened so far machining wise.

I was able to get a start on the new block, and sort out the placement of the internals.    so we're almost back on track.

the "honey do" list is strong today, but I might be able to get back out there and start cutting 35 tooth gears tomorrow....stay tuned....

I'm also glad I started the engine from the center out, or I'd of scrapped the block.   So far I've only scrapped a gear.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on December 04, 2021, 05:58:58 PM
Sorry to hear about the problem, but it sounds like you've got it sorted, Dave.

Looking forward to seeing your progress after you get the family taken care of (most important, of course!)

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on December 04, 2021, 06:25:26 PM
At least it was found before the block was all made!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on December 04, 2021, 07:51:53 PM
Hello Dave,

Sounds like the 'fix' was not too drastic. Lucky you discovered the problem when you did, before you started on the crancase itself. Hopefully it will be plain sailing from here on.

Take it easier

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 04, 2021, 08:44:44 PM
Hello Dave,

Sounds like the 'fix' was not too drastic. Lucky you discovered the problem when you did, before you started on the crancase itself. Hopefully it will be plain sailing from here on.

Take it easier

Mike

Amen to that!!!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on December 04, 2021, 10:14:56 PM
Quote
well I modelled the holes in the crank at .386" from the center.....and had a senior moment when I modeled the gear and typed in .368.....a simple transposition.....but it was enough to not see it

I guess that most of us have seen the 'crooked sentences' where some of the letters has been rearranged ....
Almost everyone that sees them can still read them and I guess that something similar is going on here + you will recognize all the digits that was part of your original plan -> I'm not sure Senior is to blame, but that it could have happened to everybody ....

Still good that you caught it so early in the build  :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 04, 2021, 10:47:39 PM
Yeah I'd say I was pretty damn lucky I started with the crank.......

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on December 05, 2021, 07:40:44 AM
That was a good save  :ThumbsUp:  :ThumbsUp:  :wine1:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 19, 2021, 04:58:46 PM
OK  between work and this, I'm just about all caught back up from the "issue"...
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on December 19, 2021, 05:00:46 PM
Wow, thats a lot of parts!
 :popcorn: :popcorn: :popcorn:
Chris
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on December 19, 2021, 05:08:16 PM
Wow!  That's an amazing amount of CAD work, Dave!  Very impressive engine.

Hope you get some time over the holidays to make more progress!

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on December 19, 2021, 05:23:46 PM
Hello Dave,

The CAD model looks great. I like the look of those external oil pumps. Hope you get some shed time soon.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 24, 2021, 01:03:33 AM
Oh we're getting closer

I'm off until the 4th.   Can't wait!!!

I've not had a vacation for over 2 years.....

Shop time!!!!
Block is coming along nicely

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on December 24, 2021, 01:12:49 AM
No vacation in two years :o wow!  Sounds like you’re long overdue.  Have fun in the shop but remember, the family would like to see you every Once in a while. :LittleDevil:

Hope your shop time is productive  :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 31, 2021, 03:08:00 AM
My vacation has been going well!    Stuff is getting done, tomorrow I focus a bit more on the engine.   I have the gear cutter I needed (32 DP #3 cutter) and I have a fixture ready to make to hold the crank webs for final turning.   I'm hoping for a good time in the shop tomorrow.   

I got a phone call from my boss today.....oh boy!.......it was good news though.....A little reward for my hard work .....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Don1966 on December 31, 2021, 03:36:05 AM
Great news bud glad to see you getting shop time in. But hey man how about pics…….. :stickpoke:


 :cheers:
Don
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 31, 2021, 03:51:17 AM
Great news bud glad to see you getting shop time in. But hey man how about pics…….. :stickpoke:


 :cheers:
Don
What's for breakfast!...
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 31, 2021, 03:56:22 AM
I'll need to make a bushing for the gear cutter...it's 1" bore, and my arbor is currently 7/8"

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on December 31, 2021, 06:16:08 AM
I'll need to make a bushing for the gear cutter...it's 1" bore, and my arbor is currently 7/8"

Dave

Doesn’t it always happen, I have a drawer full of them!  You’d think one might fit. :shrug:

Really enjoying this build Dave.  Always looking for the next installment.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 01, 2022, 11:53:16 PM
Productive day in the shop today!     I'll post some photo's and a vid a bit later, but I got the 3 main drive gears cut.   They'll need the bearing diameters finished, but i'll do that tomorrow when I start the final machining of the crankshaft.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 02, 2022, 12:39:49 AM
Just gears today.   Tomorrow, I start on the final machining of the crankshaft components

https://www.youtube.com/watch?v=erulLZQaJzI

The lathe needs a very good cleaning though first.....I could say the same about the mill!!!...

Dave


Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on January 02, 2022, 05:55:17 AM
Great to see you had some shop time, Dave!

That's nice looking gear, for sure!  :ThumbsUp: :popcorn:
Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on January 02, 2022, 10:38:25 AM
Holliday and shoptime  - things are improving for you or ....
Anyway nice to see that you are moving forward on this build again.

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 02, 2022, 10:59:36 AM
Great to see you had some shop time, Dave!

That's nice looking gear, for sure!  :ThumbsUp: :popcorn:
Kim

3 gears!     :whoohoo:
I'm looking forward to finishing the crank!   I needed the center gear before I could do the final operations to the crank.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Don1966 on January 02, 2022, 10:03:11 PM
Nice gears Dave….. :ThumbsUp:


 :cheers:
Don
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 02, 2022, 11:35:52 PM
Great progress on the crankshaft segments.  The final operation for each segment is to turn and face the unfinished end while mounted by the finished end in a "insitu" fixture in the lathe.   I've gotten to #3 of 6 segments, and I'm calling it for tonight... One wrong move now and the parts are junk...so come back and finish it when I'm fresh.......Here's some photo;s including 2 segments bolted together!...

1   turning fixture. It stays in the lathe until all the sections are done

2   The semi finished segment mounted in the fixture

3    The bearing diameter turned and the bearing fitted

4    Two finished segments with a bearing mounted in place in the center
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on January 02, 2022, 11:59:16 PM
Slick setup! And knowing when to walk away and rest/reset is a key workshop skill.


 :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2022, 12:05:51 AM
Slick setup! And knowing when to walk away and rest/reset is a key workshop skill.


 :ThumbsUp:

Keeping it all clean is really tough.....it doesn't take anything to make it all run out...

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on January 03, 2022, 11:22:02 AM
Splendid  :ThumbsUp:  :ThumbsUp:  :wine1: Good to finally get some workshop time  :)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2022, 09:25:08 PM
Crank is done!!!    this will be the hardest part to make, so i feel pretty good about the rest of the model!    Hardened crank pins, 8 ball bearing main bearings, and the center power take off gear just like the prototype.   The crank, a CAD model of it, and a picture the real thing with the crank case split

Interestingly enough, the best way to get the small chips off the parts while I was machining was a clean toothbrush!!.. 

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on January 03, 2022, 09:31:49 PM
Looks good Dave.   :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on January 03, 2022, 09:40:20 PM
Very impressive!!


In the picture of the real engine, the gear teeth extend above the crank sides. Did you change the gearing on your design, or is that gear not there yet?  :thinking:


 :popcorn: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2022, 09:46:40 PM
Very impressive!!


In the picture of the real engine, the gear teeth extend above the crank sides. Did you change the gearing on your design, or is that gear not there yet?  :thinking:


 :popcorn: :popcorn: :popcorn:

The real engine is plain bearing, I'm using 25 x 32 x 4mm ball bearings.   Those are the parts sitting above the crank gear
The crank is composed of 6 crank sections and a center gear.   Here's a model of a crank section
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on January 03, 2022, 09:48:38 PM
Very impressive!!


In the picture of the real engine, the gear teeth extend above the crank sides. Did you change the gearing on your design, or is that gear not there yet?  :thinking:


 :popcorn: :popcorn: :popcorn:

The real engine is plain bearing, I'm using 25 x 32 x 4mm ball bearings.   Those are the parts sitting above the crank gear
Gotcha!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 03, 2022, 10:12:48 PM
Hello Dave,

The crankshaft came together quickly towards the end, and before the end of your holiday break. Well done, it looks fantastic.

Did you measure the run-out before each section was added? If not, you can always mount and clamp two adjacent bearings to Vee blocks and check the runout of the each section.  The whole cranksfaft looks long and flexible, so the eight equi-spaced bearings should have little difficulty in pulling out a few thou of run-out, That is, if there is any.

Fantastic work

Mike   :praise2: :praise2: :praise2:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2022, 10:24:43 PM
Hello Dave,

The crankshaft came together quickly towards the end, and before the end of your holiday break. Well done, it looks fantastic.

Did you measure the run-out before each section was added? If not, you can always mount and clamp two adjacent bearings to Vee blocks and check the runout of the each section.  The whole cranksfaft looks long and flexible, so the eight equi-spaced bearings should have little difficulty in pulling out a few thou of run-out, That is, if there is any.

Fantastic work

Mike   :praise2: :praise2: :praise2:

I checked the fixture before and after each section was turned and it was consistently in the .0002-.0004" radially and axial run out range.  That said, I don't think I could do any better if I tried.     I've not measured it yet, but I will, but I think it'll be fine.   The fixture worked very well, and asl long as you were gentle, it stayed put.   A somewhat common occurance was to slightly marr the face surface, so I would take a thou off, just to clean it up after each couple of sections.     To drive the thickness, I made up a gage block stack, and set the axial distance from the face of the fixture to the tool, and then set the bed dial indicator to zero, so I knew where to go as I turn/faced the crank cheek for the bearing.    Just keep and eye on the fixture, and keep checking it with a dial indicator to make sure it stays true.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 03, 2022, 10:54:17 PM

I checked the fixture before and after each section was turned and it was consistently in the .0002-.0004" radially and axial run out range.  That said, I don't think I could do any better if I tried.     I've not measured it yet, but I will, but I think it'll be fine.   The fixture worked very well, and asl long as you were gentle, it stayed put.   

.  .  .  .  .  .

  Just keep and eye on the fixture, and keep checking it with a dial indicator to make sure it stays true.

Dave

If you keep checking the fixture and it stays put and always indicates true; then there is not much else you can do. The crankshaft will be as true as you can make it.

Did I say it looks fantastic.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2022, 11:08:04 PM

I checked the fixture before and after each section was turned and it was consistently in the .0002-.0004" radially and axial run out range.  That said, I don't think I could do any better if I tried.     I've not measured it yet, but I will, but I think it'll be fine.   The fixture worked very well, and asl long as you were gentle, it stayed put.   

.  .  .  .  .  .

  Just keep and eye on the fixture, and keep checking it with a dial indicator to make sure it stays true.

Dave

If you keep checking the fixture and it stays put and always indicates true; then there is not much else you can do. The crankshaft will be as true as you can make it.

Did I say it looks fantastic.

Mike

Thanks Mike!!!    I'm excited!     Rods and bearings next!

I'm going to pick up the gears for the distributors /fan this week, so I can finalize the rest of the gears.    Lots more gear cutting in my future!!!...

Dave

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on January 03, 2022, 11:15:23 PM
Woa - now this is a major point in this build that you just completed and it looks fantastic  :praise2:

Looking forward to the rest as you find time  :cheers:     :popcorn:

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2022, 11:19:17 PM
Woa - now this is a major point in this build that you just completed and it looks fantastic  :praise2:

Looking forward to the rest as you find time  :cheers:     :popcorn:

Per
Definitely the hardest part of this build I think    I think if I can build this, I can build the rest.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on January 04, 2022, 12:42:04 AM
Congratulations on getting the crankshaft done successfully, Dave! It looks great! :ThumbsUp: :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Hugh Currin on January 04, 2022, 03:24:43 PM
Dave:

Very nice results. It almost looks like 6 cranks in bearings connected together, as in each is solid by itself only needing to transmit torque on down the line. Very unique and allows roller bearings. I'm surprised the original used bushings.

How do you keep the toothbrush clean??

Again, great results. Thanks.

Crank is done!!!

Interestingly enough, the best way to get the small chips off the parts while I was machining was a clean toothbrush!!..
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 04, 2022, 04:42:25 PM


How do you keep the toothbrush clean??




Ya know Hugh,   I have no idea.   I have not noodled why the brush works and nothing else would, there doesn't appear to be anything on the brush....I suspect electrostatic effects....but all I know is it worked amazingly well!!!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 05, 2022, 08:55:08 PM
Bevel gears for the fan drive on order....they  dont give those away at Mcmaster carr!....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on January 06, 2022, 03:30:56 PM
Dave, why not cut your own bevel gears? Not that much harder than the straight ones you cut.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 06, 2022, 10:40:54 PM
Other things to machine....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 09, 2022, 03:06:22 AM
In the interest of getting accurate shaft centerlines, I'm working on the fan shaft gears and the output shaft gear trains, so I can measure that up and work it into the block dimensions.  I got the bevel gears so I'm working that out now.   Hopefully I'll have some pictures to show tomorrow....



Work is about to get nuts....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on January 10, 2022, 12:45:51 AM
I hear you steamer. I'm finally making good progress on the radials and I'm hearing 7 days 12 hours at the end of February. Just plug along when you get time and the crazy will end someday.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 10, 2022, 01:12:03 AM
I hear you steamer. I'm finally making good progress on the radials and I'm hearing 7 days 12 hours at the end of February. Just plug along when you get time and the crazy will end someday.

Thanks buddy....The struggle is real!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: ozzie46 on January 10, 2022, 12:39:38 PM
I hear you steamer. I'm finally making good progress on the radials and I'm hearing 7 days 12 hours at the end of February. Just plug along when you get time and the crazy will end someday.

UH Wait Radials What radials?

Ron
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 10, 2022, 10:12:21 PM
I hear you steamer. I'm finally making good progress on the radials and I'm hearing 7 days 12 hours at the end of February. Just plug along when you get time and the crazy will end someday.

UH Wait Radials What radials?

Ron

 8) I know something you dont........ :lolb:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: ozzie46 on January 10, 2022, 10:55:46 PM
Oh great!! Now the suspense will keep me awake for quite awhile! :hammerbash: :hammerbash: :hammerbash:
Ron
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on January 10, 2022, 11:05:03 PM
I meant readables, books. Damn spell check.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: ozzie46 on January 11, 2022, 11:39:32 AM
Yeah. Right, and moon is made of green cheese.  ::) ::) ::)

Ron
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on January 11, 2022, 10:32:05 PM
Oh man I love cheese.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 11, 2022, 10:34:29 PM
Oh man I love cheese.


 8)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 16, 2022, 02:05:01 AM
Just about finished with the initial drive gears....output shaft and fan drive.    The fan drive is press fit   ( .002") so I don't think it's going anywhere!

compared to the original....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 16, 2022, 09:38:23 AM
Ňh! So sweet
Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on January 16, 2022, 10:40:44 AM
That's some nice work right there too bad you have to hide it in the engine.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on January 16, 2022, 10:41:50 AM
Great - so now you also have the centre distances  :ThumbsUp:

What do you plan to do next - the block, or ?

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 16, 2022, 10:56:32 AM
Great - so now you also have the centre distances  :ThumbsUp:

What do you plan to do next - the block, or ?

Per
Probably finish the connecting rods.    I should have the new block all sorted out by then     I'm still prognosticating over lubrication solutions....its getting close.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 16, 2022, 12:51:02 PM
That's some nice work right there too bad you have to hide it in the engine.

Steve...it is so nice to use a lathe that you can explicitly trust...I ask for it...it gives it!!!    .Turning the bearing diameters to size within .0005" was really easy once set up correctly.   Rinse and repeat!

As a side note, I have the spindle bearing clearance adjusted to the SouthBend spec, for really tight work, it might want to be tightened up a bit...but it did well enough!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on January 16, 2022, 03:02:32 PM
That is work to make even Herr Mezger proud! Very impressive.   :ThumbsUp: :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 16, 2022, 05:08:12 PM
That is work to make even Herr Mezger proud! Very impressive.   :ThumbsUp: :cheers:

Thanks Ron....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 16, 2022, 06:20:08 PM
Final thrust bearing design for both the crank and the output shaft, though I plan on doing the fan layshaft in a similar manner, its not laid in yet

I came up with this while doing the new block.  Replace the crank bearings either side of the gear with flanged bearings of the same size, so drop in replacements.   so now the crank is captured at the center...which growth wise minimizes  the movement axially.   Additionally, I have needle roller bearings on the output shaft with bronze thrust washers either side.  The gear is pressed and woodruff keyed to the shaft which is a 8mm piece of Thompson shafting  ( case hardened and ground)   The flange of the crank bearing is let into the thrust washers such that the thrust washers can not rotate, and are radially supported on the ID by the stationary OD race of the needle bearings.   Easy to lubricate with some cross holes and as thrust loads are incidentals, it should be fine.   Drive to the oil pump will go to the left of the picture off the end of the output shaft....as is prototypical.   Some form of oldham coupling, but I'm entertaining moving the pump into the block but accessible from the left end.....stay tuned!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on January 17, 2022, 11:52:30 PM
That crankshaft is deeeeeeeeeelux Dave.   Just superb!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 18, 2022, 12:13:31 AM
That crankshaft is deeeeeeeeeelux Dave.   Just superb!

Thanks Craig,  its starting to fill in nice....

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Art K on January 18, 2022, 02:56:14 PM
Dave,
Things are looking very good!  Great that you can just swap out the center bearings and have thrust under control.
Art
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on January 22, 2022, 08:16:21 AM
Excellent  :praise2:  :praise2: That's a neat solution for the thrust bearings  :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 31, 2022, 12:09:14 AM
OK so full design intent  installed.     Everything but the scavenge side on the right side block with strainers....But not tonight
The pump is iin  as is the drive for it, and the pressure feed passages to the spray bar above.  I also have the scavenge delivery passages in the left block

What remains is the fan drive items, which I'll get into, and the aforementioned scavenge ports and strainers  ect on the left block.

I'll build the output shaft and the oil/scavenge pump system next and debug on the bench.   Then the fan drive.   THEN  the blocks...that will give me a chance to develop everything that goes in the block before I cut metal on the block ...

Oil and scavenge pumps were sized by copying Ron Colonna's pump dimensions from his Offy, which is only slightly smaller than this engine, and had a pressure lubed/plain bearing main and rods...so this should be more than enough to feed this girl..

I have distributors designed and modeled, but before i finalize, I need to get my cross helical gears from across the pond....its on the list

Work has been crazy.....67 hours last week,,,,and they want more....I played hooky today.....

Dave

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 31, 2022, 11:33:05 AM
Hello Dave,

That's a neat little pump and installation with all the pressure and delivery passages machined into the blocks. I see you have gone away from the idea of an externally located pump. You said the external location was to give access to the pump during development. You are obviously more comfortable with this version of the design, because when the two sides of the crankcase are eventually bolted together, it's in there for keeps.

67 hours last week...... you can  :censored: that

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on January 31, 2022, 11:38:26 AM
Looks like a very neat and easy installation of the pumps  :ThumbsUp:

I must admit that I'm not sure I got all the detail right in my head. I presume that the two lower holes are the oil entry points for the two of tree pumps - but what is the the input to the one closest to the pumps input shaft ?

The recesses on the pumps outputs, are they for the o-rings  :thinking:

Great that you got a good income after some hard times, but I understand if you would have liked it, to be more even workload over time ....

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: JonC on January 31, 2022, 12:59:15 PM
Hi Dave,

Incredible build so far and love it every time there's a bit more progress to be admired. The thrust bearing idea is excellent, are you using 25x32x4 bearings? I'm using these on the DFV crank but cannot find a flanged version of it.

Thanks

Jon
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 01, 2022, 04:13:02 AM
Hello Dave,

That's a neat little pump and installation with all the pressure and delivery passages machined into the blocks. I see you have gone away from the idea of an externally located pump. You said the external location was to give access to the pump during development. You are obviously more comfortable with this version of the design, because when the two sides of the crankcase are eventually bolted together, it's in there for keeps.

67 hours last week...... you can  :censored: that

Mike

14 hour day today too.....but they gave me a nice raise.....

Mike, You sir are correct on all counts.....here's the scoop....no matter how I tried to do it, that external pump looked like Q(*E(*Q .    It is NOT how the 917 engine looks...  My previous comments about fiddly bits inside the engine is still accurate.    To get around that, instead of running the pump with a gear train at about 1/2 engine speed, I'll be running this one at engine speed.   Pump speed is well within limits for a gear pump ( pitch line velocity below 20 m/s.    In this application it's under 3 m/s at 8000 rpm)    But this pump needs to be reliable....so I'll be following a theme that has already saved my bacon on thius project....work from the inside out.     SO   to develop this pump and make it reliable, it will be the next thing on the list to build, followed by the power layshaft and the fan/distributor layshaft.    And I'm very happy I'm taking this path as it's like the REAL one......

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 01, 2022, 04:21:55 AM
Looks like a very neat and easy installation of the pumps  :ThumbsUp:

I must admit that I'm not sure I got all the detail right in my head. I presume that the two lower holes are the oil entry points for the two of tree pumps - but what is the the input to the one closest to the pumps input shaft ?

The recesses on the pumps outputs, are they for the o-rings  :thinking:

Great that you got a good income after some hard times, but I understand if you would have liked it, to be more even workload over time ....

Per
What you see there Per is 3 pumps stacked on top of each other.    From the left to right....the first is the pressure pump,   The second and third are scavenging pumps.  They each have 1.5 x the capacity of the pressure pump.     the round recesses on the side are for seals that seal the pump agianst each half of the engine block.   All passages are drilled passages leading to the top of the block and down a stand pipe with 7 nozzles.   1 for each crank bay and 1 for the gear bay in the middle.   The scavenge pumps will draw from the two bottom sump wells with strainers down low.   All that will be on the RIGHT side engine block half.   Not shown..    JUST like the real one.   there will be 1 hose into the right block feeding the pressure pump from the scavenge oil tank, and the two scavenge pumps down to a hose on the left side of the block up front.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 01, 2022, 04:28:01 AM
Hi Dave,

Incredible build so far and love it every time there's a bit more progress to be admired. The thrust bearing idea is excellent, are you using 25x32x4 bearings? I'm using these on the DFV crank but cannot find a flanged version of it.

Thanks

Jon

Thanks Jon,   The McMaster Carr part number is in the top left of the corner of the picture below. 
https://www.mcmaster.com/4390N142/

Dave



Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: fumopuc on February 01, 2022, 07:11:11 AM
Hi Dave, I am following along quietly all time.
Impressive to watch the progress.
There is an always upcoming desire to ask you for the plans/drawings if it is coming closer to the final stage.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 01, 2022, 11:39:03 AM
Hi Dave, I am following along quietly all time.
Impressive to watch the progress.
There is an always upcoming desire to ask you for the plans/drawings if it is coming closer to the final stage.

That will be a ways off sir.   But I think it doable....not sure which decade... :lolb:at this rate

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 01, 2022, 11:46:21 AM
The other place to look for all kinds of small bearings is Fast Eddy's


https://www.fasteddybearings.com/

They provide specialty bearings to the RC industry.  Good stuff

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on February 01, 2022, 01:47:30 PM
67 hours is insane.  Many years ago, a group of us ‘hot shots’ started our own company.  We put in hours like that for around two years… but then we were working for ourselves so that is different.  We learned a valuable lesson on marketing; much better to have a crappy product and great marketing.  Unfortunately we were the opposite. After two years we realized we were getting nowhere and probably would continue to go no where.  It was time to move on.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 07, 2022, 12:33:31 AM
Made some progress today!!

Here are all the major parts for the pressure and 2 scavenge pumps for the engine.   First operation on all is complete.   I designed the pump so that all critical dimensions could go in with 1 set up and 1 tool...minimizing the errors as much as I can.   Now  they get chopped off the bar, and mounted, finished face down, on a fixture so the back side of each part is finish machined.    This will maximize the chance that the parts are parallel.   Next each part will get its oil ports put in, and then cleaned up and deburred.

Productive afternoon!

Maybe with CNC   I can keep up with Chris! :insane: :Doh:

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 07, 2022, 02:32:47 AM
Nice! The planning on those parts looks well worth it.   :popcorn: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: JonC on February 07, 2022, 09:27:33 AM

[/quote]

Thanks Jon,   The McMaster Carr part number is in the top left of the corner of the picture below. 
https://www.mcmaster.com/4390N142/

Dave
[/quote]

Thanks Dave, very helpful. Back to the drawing board now to fit it in.

Jon
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 07, 2022, 04:07:54 PM
With the Everything shortage  I've had a hard time finding any of these at a reasonable cost.  I hope it gets better with time.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 27, 2022, 03:31:42 PM
OK  1 step forward, and 3 bask..... :lolb:

If you look at the machined parts above closely, you will see that the gears CAN"T mesh.... :toilet_claw:      :Doh:

OK....drop back and fix it.    I redrew and simplified the pump, .....correctly this time.

I also decided that it nees a lot less volume.   so I gear reduced it...as is prototypical

My gear cutters are here, and I have another piece of bronze!    Off to the mill!!!


Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 28, 2022, 01:28:23 AM
OK   that got it this time!!!   Next will be the pump gears, but if I'm cutting gears, I'm thinking of cutting all of them....as the set up is a bit of a pain in the ass

After second and final ops on these part of course....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 28, 2022, 01:57:20 AM
OK  1 step forward, and 3 bask..... :lolb:

If you look at the machined parts above closely, you will see that the gears CAN"T mesh.... :toilet_claw:      :Doh:

OK....drop back and fix it.    I redrew and simplified the pump, .....correctly this time.

I also decided that it nees a lot less volume.   so I gear reduced it...as is prototypical

My gear cutters are here, and I have another piece of bronze!    Off to the mill!!!
I'm confused about the picture in that post, the straight gear on the top shaft, next to the bevel gears, looks to be off to the side of the gear below it? Shouldn't it be meshing with the gear below, like it was in earlier pictures??
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 28, 2022, 02:09:08 AM
OK  1 step forward, and 3 bask..... :lolb:

If you look at the machined parts above closely, you will see that the gears CAN"T mesh.... :toilet_claw:      :Doh:

OK....drop back and fix it.    I redrew and simplified the pump, .....correctly this time.

I also decided that it nees a lot less volume.   so I gear reduced it...as is prototypical

My gear cutters are here, and I have another piece of bronze!    Off to the mill!!!
I'm confused about the picture in that post, the straight gear on the top shaft, next to the bevel gears, looks to be off to the side of the gear below it? Shouldn't it be meshing with the gear below, like it was in earlier pictures??

broken mate.......Fusion is a pain in the ass....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jasonb on February 28, 2022, 07:23:36 AM
Chris I think it's this pic that shows the pump gears won't mesh as either the ctrs are wrong or the pockets not a big enough diameter.

Would have thought that would show up on the simulation in F360 which basically shows what the machine is going to cut and you could have seen there was not enough gap between the pockets for the gears to mesh.

(https://www.modelenginemaker.com/index.php?action=dlattach;topic=10504.0;attach=132934;image)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 28, 2022, 11:10:03 AM
Chris I think it's this pic that shows the pump gears won't mesh as either the ctrs are wrong or the pockets not a big enough diameter.

Would have thought that would show up on the simulation in F360 which basically shows what the machine is going to cut and you could have seen there was not enough gap between the pockets for the gears to mesh.

(https://www.modelenginemaker.com/index.php?action=dlattach;topic=10504.0;attach=132934;image)

Ah yes....but we all have our days....don't we?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 28, 2022, 01:04:23 PM
Chris I think it's this pic that shows the pump gears won't mesh as either the ctrs are wrong or the pockets not a big enough diameter.

Would have thought that would show up on the simulation in F360 which basically shows what the machine is going to cut and you could have seen there was not enough gap between the pockets for the gears to mesh.

(https://www.modelenginemaker.com/index.php?action=dlattach;topic=10504.0;attach=132934;image)
That's not the picture I was talking about, but the one before it showing the cad view with all the shafts and gears.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jasonb on February 28, 2022, 01:13:24 PM
Yes the large gear next to the bevel is out of place om the main assembly CAD possibly missing a constraint.

But Dave said the pump gears would not mesh, so its inside the pump where the problem is, still not sure if it was gear ctr spacing or hole size but as it looks like all 4 pump parts have been made again probably the former.

I usually find the CAM gets it right and it's me that messes something up like entering the tool height as 200mm instead of 20mm  :'(
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: propforward on February 28, 2022, 05:53:10 PM
I believe Chris means the picture attached here. The gear A (crudely arrowed) should be moved over - which is what Dave was saying - a broken mate. I get that in solidworks plenty, just the same as Fusion 360 I'm sure. The number of times I've put an assembly away, only for it to fly all over the place when I open it the next day..............  :facepalm2:

Two separate things - the cad mate and the actual meshing, I guess.


What an epic thread. I must have not looked in before because it's an I.C. engine - so again  :facepalm:

Really top work Dave, bravo sir. I shall be following along - I have enjoyed catching up with my lunchtime sammo.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 28, 2022, 05:56:52 PM
Thats the one Stuart! Sounds like Dave has that one worked out with the broken constraint - fusion does do some odd things with joints sometimes...
And agreed, this design is amazing.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on March 01, 2022, 01:12:37 AM
I believe Chris means the picture attached here. The gear A (crudely arrowed) should be moved over - which is what Dave was saying - a broken mate. I get that in solidworks plenty, just the same as Fusion 360 I'm sure. The number of times I've put an assembly away, only for it to fly all over the place when I open it the next day.............. 

Happens with Alibre too, if you don’t get everything constrained properly.

Dave: many ways to get it wrong, only one way to get it ‘right’.  You’re making progress, regardless of the setbacks.  Looks GREAT.

Back when I was a student in engineering, a student asked the professor once, “Professor, why don’t you give partial credit for test answers that are nearly correct?”.

I loved he’s answer, “When you get it ‘almost right’ the rocket still blows up”. 

Classic!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on March 01, 2022, 04:52:37 PM
I believe Chris means the picture attached here. The gear A (crudely arrowed) should be moved over - which is what Dave was saying - a broken mate. I get that in solidworks plenty, just the same as Fusion 360 I'm sure. The number of times I've put an assembly away, only for it to fly all over the place when I open it the next day.............. 

Happens with Alibre too, if you don’t get everything constrained properly.

Dave: many ways to get it wrong, only one way to get it ‘right’.  You’re making progress, regardless of the setbacks.  Looks GREAT.

Back when I was a student in engineering, a student asked the professor once, “Professor, why don’t you give partial credit for test answers that are nearly correct?”.

I loved he’s answer, “When you get it ‘almost right’ the rocket still blows up”. 

Classic!
I hear ya.    7000 pound load test piece for diamond turning lathe.   The hydrostatic spindles were mine.   
Chucks are 24"

It held the load so my math was right
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on March 01, 2022, 04:55:39 PM
I believe Chris means the picture attached here. The gear A (crudely arrowed) should be moved over - which is what Dave was saying - a broken mate. I get that in solidworks plenty, just the same as Fusion 360 I'm sure. The number of times I've put an assembly away, only for it to fly all over the place when I open it the next day.............. 

Happens with Alibre too, if you don’t get everything constrained properly.

Dave: many ways to get it wrong, only one way to get it ‘right’.  You’re making progress, regardless of the setbacks.  Looks GREAT.

Back when I was a student in engineering, a student asked the professor once, “Professor, why don’t you give partial credit for test answers that are nearly correct?”.

I loved he’s answer, “When you get it ‘almost right’ the rocket still blows up”. 

Classic!
I hear ya.    7000 pound load test piece for diamond turning lathe.   The hydrostatic spindles were mine.   
Chucks are 24"

It held the load so my math was right
Wow. You must have had BIG shop elves!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on March 05, 2022, 04:20:59 PM
OK   Oil pump body parts and covid test today......and a presentation for Monday...........

I did get my gear cutters that I need....

Dave


Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on March 05, 2022, 05:34:39 PM
With big stuff you usually just get one go so better get it right ::) An impressive lathe.

I can screw things up with pencil and paper or 2D CAD  :(  :facepalm:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on March 05, 2022, 06:00:11 PM
With big stuff you usually just get one go so better get it right ::) An impressive lathe.

I can screw things up with pencil and paper or 2D CAD  :(  :facepalm:

Yeah there was a half a million sunk into the one of a kind spindles alone .....no pressure.....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on March 06, 2022, 11:58:43 PM
First ops complete on the pump parts, and the fixture is made.    Not much to talk about this weekend, but hopefully more this week.    I have the fixture which should allow the second ops on the pump body.   The we cut some gears....

Worked this weekend.......sigh....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on March 28, 2022, 12:40:27 AM
finishing off the vises for the group this weekend, and i'm painting them...perfect time to get some work done on the 917 engine    Oil and scavenge gear pump bodies up to 2nd op   next is to drill the passages....
water bottle cap for reference...

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on March 28, 2022, 01:02:22 AM
More great details.    :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on March 28, 2022, 02:33:51 PM
Nice to see you back to making parts.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on March 28, 2022, 04:06:57 PM
Working too many damn hours...
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on March 28, 2022, 10:26:12 PM
Yeah me too. I'm on ten hour days, 7 days a week and we are bout to go to 12 hours.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on March 28, 2022, 10:53:38 PM
Yeah me too. I'm on ten hour days, 7 days a week and we are bout to go to 12 hours.

I remember those days… Being retired it’s a memory, I didn’t say a fond memory either.   :Doh:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Art K on March 29, 2022, 01:59:58 AM
Dave,
Great work on the 917! I had a problem with the assembly on the Offy. I was constraining two flat surfaces and two opposite corner holes on a cover plate. It would only constrain one and would rotate around it. After seeking help on Alibre forum it was found that the holes were .0005 off and didn't match up. I fixed that and all was good. I had been working five 10 hour days since January 2020. I get to quarantine the rest of the week as I tested positive.
Art
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on March 29, 2022, 10:20:02 AM
Art, Craig, Steve and Chris
Be safe out there boys!    and thank you very much for looking in.     Work has been crazy since our new release, and I'm already neck deep in a new project, so at least they want me to stick around.

Art.   It's really hard with these small parts to be assured of geometry.   The best palliative ive found thus far is to do all the machining in one set up.   Even that doesn't always work.    The end cap on the pump doesn't seem very flat, and I suspect it will need to be remade for instance.    Getting 4 parts to string together on a 1/8" shaft is asking for trouble.....
I hope you get through your quarantine uneventfully and get back neck deep in that little Offy.....that's a sweet build!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 04, 2022, 11:35:56 AM
Well  It appears I'll be able to save that part, and I've started on setting up to cut the gears for the project.    That includes the pump gears, the pump drive gears and all the cam shaft drive gears.....I think I'm just going to get all that out of the way.  I also need to update my lathe mounted keyway cutter as I've got some keyways to make as well....much to do

I just finished my small part of the vise project with Nigel over at Go Create Hobby Machine Shop on YouTube.      Now that's done, I should have a bit more time.    I want to get the gears done before the good weather really gets here....."Rushforth" has been languishing far too long, and she needs to have her repower completed, and be used!!!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on April 04, 2022, 03:05:10 PM
Quote
"Rushforth" has been languishing far too long, and she needs to have her repower completed, and be used!!!
Glad you're making a bit of headway, sounds like you're a busy boy. So what's this "Rushforth"?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on April 04, 2022, 04:42:09 PM
Hello Dave

Pleased you were able to take a few moments to look at your hobby interests. It must be hard to remember you are trying to drain the swamp when you are up to your *** in someone else's alligators.

It's good that you have been able to progress the 917's pumps a little and it would be even better if you could get the Yamaha engine into 'Rushforth' with spring and a long summer ahead. Just think, a nice cup of tea and cucumber sandwiches on the river bank or is it a burger and a Budweiser or two?

Any sign of the printed parts?

Cheers

Mike or should that by Myk.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on April 04, 2022, 05:12:33 PM
Not trying to derail but with the current trend it seems a simple transition into electric for the mistress. Maybe a battery pack that can be removed and charged at home. A motor and controller.  Your  not trying to set a speed record so battery life might be better than expected. 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 04, 2022, 06:39:58 PM
Hello Dave

Pleased you were able to take a few moments to look at your hobby interests. It must be hard to remember you are trying to drain the swamp when you are up to your *** in someone else's alligators.

It's good that you have been able to progress the 917's pumps a little and it would be even better if you could get the Yamaha engine into 'Rushforth' with spring and a long summer ahead. Just think, a nice cup of tea and cucumber sandwiches on the river bank or is it a burger and a Budweiser or two?

Any sign of the printed parts?

Cheers

Mike or should that by Myk.

I printed them Miks....gotta get them in a box and off to you

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on April 04, 2022, 06:45:14 PM
 :ThumbsUp: :ThumbsUp:

no rush, they will keep

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 04, 2022, 07:15:30 PM
Quote
"Rushforth" has been languishing far too long, and she needs to have her repower completed, and be used!!!
Glad you're making a bit of headway, sounds like you're a busy boy. So what's this "Rushforth"?


Do a forum search under Rushforth and you'll find it
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on April 04, 2022, 08:44:08 PM
Search function on here seems a bit odd sometimes. I did a search for Rushforth and "Rushforth" before asking, and with no result. Then tried again a few minutes ago, again without results, other than today's mentions. Then one more time and found it along with several other mentions which had not shown up previously at all. I have no idea what was different, almost certain not spelling because the "suggestions" that pop up weren't misspelled. :headscratch:
Anyway, Thanks!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on April 04, 2022, 08:47:32 PM
Search function on here seems a bit odd sometimes. I did a search for Rushforth and "Rushforth" before asking, and with no result. Then tried again a few minutes ago, again without results, other than today's mentions. Then one more time and found it along with several other mentions which had not shown up previously at all. I have no idea what was different, almost certain not spelling because the "suggestions" that pop up weren't misspelled. :headscratch:
Anyway, Thanks!
If you were in the thread when you did the search, it just searched the thread, best to be at the forum top when searching. Hope that helps.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on April 04, 2022, 08:48:44 PM
That probably explains it, Thanks Chris.
And that's a nice boat, Dave.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 05, 2022, 10:27:19 AM
Thanks Ron.    I am currently putting a Yanmar 9Hp single diesel in.     Somehow Mama doesn't feel enamored with sitting in the middle of a pile of firewood.....so I'll be taking a page from the motor lauch Scolopendra
https://www.bing.com/videos/search?q=boat+scolopendra&view=detail&mid=F53E033EE79E5957F6A7F53E033EE79E5957F6A7&FORM=VIRE

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on April 05, 2022, 12:31:45 PM
Hello Dave,

Nice looking hull lines on Scalopendra but not as nice as the long tail 917 bodywork

Just saying

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 05, 2022, 02:59:20 PM
Hello Dave,

Nice looking hull lines on Scalopendra but not as nice as the long tail 917 bodywork

Just saying

Mike

Mama and I need a break Mike...  we need to do something together that doesn't involve taking care of a cancer patient.   Been  long 6 years......just sayin
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 05, 2022, 11:10:11 PM
Hello Dave,

Nice looking hull lines on Scalopendra but not as nice as the long tail 917 bodywork

Just saying

Mike

Mama and I need a break Mike...  we need to do something together that doesn't involve taking care of a cancer patient.   Been  long 6 years......just sayin

Don't worry boysand girls  I'm not stopping the build or going anywhere.   Just taking advantage of the summer months
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Don1966 on April 05, 2022, 11:43:50 PM
Enjoy to vacation buddy a well deserved one….


Don
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Art K on April 06, 2022, 03:01:54 AM
Dave,
You and the wife take care of yourselves we can wait!
Art
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 23, 2022, 09:38:37 PM
Not a huge thing, but I picked up some tooling today for this project.   A 0.8 to 1.25 bore gage.....got a very good price on it too.
This will be for the cylinder bore effort and maybe even the crank bearing bores!....just   1.259

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on April 23, 2022, 11:00:46 PM
Sounds like a great 'find'. Just what you need for accurate bore measurements.

Cheers

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on April 24, 2022, 12:19:18 AM
You will not regret buying it. I started getting them on ebay about 5 years ago. Way easier to measure a bore.


Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on April 24, 2022, 05:23:34 AM
A nice little piece of kit, Dave!

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: propforward on April 24, 2022, 11:55:32 AM
Nice piece of kit - that will be tremendously useful.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on May 01, 2022, 11:47:41 PM
Got my bore gage today.    It's sweet!   Needed a touch of cleaning, but it works very well.   I'm going to go find a 1" ring gage master as a check point...

Also picked up a 1-2 mic with tenths vernier and a friction thimble   It checks out accurate....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on May 02, 2022, 12:24:06 AM
   I'm going to go find a 1" ring gage master as a check point...

Dave

If you can find a second 1" ring gauge at a reasonable price, let me know.

Cheers

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on May 02, 2022, 12:49:22 AM
New tools!   :whoohoo:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on May 02, 2022, 08:28:35 PM
   I'm going to go find a 1" ring gage master as a check point...

Dave

If you can find a second 1" ring gauge at a reasonable price, let me know.

Cheers

Mike

I've seen at least 3 on ebay today in the $20 range used.   I found a 21.4315mm gage, the bore on the 917 engine is 21.488....so close enough to what I'm trying to measure.   ( the bore could be 21.431 just as easily as 21.488    )

I think I paid $43.59 with free shipping and it's still in its sealed wax coating!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on May 02, 2022, 08:40:49 PM

I've seen at least 3 on ebay today in the $20 range used.   I found a 21.4315mm gage, the bore on the 917 engine is 21.488....so close enough to what I'm trying to measure.   ( the bore could be 21.431 just as easily as 21.488    )

I think I paid $43.59 with free shipping and it's still in its sealed wax coating!

Dave

Thanks Dave

Some on ebay UK starting around Ł40, but all too big a diameter for my gauge. I will keep looking

Mike

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Craig DeShong on May 04, 2022, 04:04:55 PM
New tools!   :whoohoo:

You can never have enough toys.

Great find Dave.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on May 09, 2022, 02:31:31 AM
Got some nice pictures of stuff I've not seen a good one for.    Very helpful with respect to the cam covers, the front engine mount/bell housing, and the exhaust pipes
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on May 09, 2022, 02:33:06 AM
And another
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on May 09, 2022, 02:42:21 AM
That last picture looks like the engine out of a sci-fiction spaceship!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on May 09, 2022, 03:28:15 AM
Working on Cleaning up the front engine mount.    That last picture really clarifies it.

Getting closer..... 

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on May 09, 2022, 09:14:55 AM
Morning Dave,
Why is it always like that? If you have collected a thousand photos, there are always details that are not visible. That's some good information you found. I like how you were able to use it to refine the front of the 3D model.

Cheers

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on May 10, 2022, 12:15:12 AM
Oh I'm having some fun....no worries....with all the crap going on in my life....I'll take the little victories.     Much refinement of some of the auxiliaries has been accomplished..   and The front engine mount is coming together in a much more pleasing and accurate way. 

I wish Fusion360 CAD didn't suck so bad...but    first world problem right?

Dave
 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on May 16, 2022, 12:04:18 PM
Got a good start on all the internal gears yesterday.  Nothing particularly interesting, as I spent the day making "wafers", but LOTS of wafers

I'll post some photo's later today ....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: propforward on May 16, 2022, 09:18:49 PM
Any time in the shop is a good time.  :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on May 16, 2022, 11:35:27 PM
Any time in the shop is a good time.  :ThumbsUp:

Give me a bit.     need to make a few more waffers!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on May 18, 2022, 01:17:44 AM
A little inspiration......Steve doing Steve things

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on May 18, 2022, 01:34:27 AM
He invented the GoPro??!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on May 18, 2022, 02:31:10 AM
He invented the GoPro??!
A little inspiration......Steve doing Steve things

Nah   I'd call it a counterweight! 8) :stir:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on May 18, 2022, 10:47:00 PM
A little inspiration......Steve doing Steve things

He certainly knew how to drive fast and he certainly knew how to make movies. Ground breaking stuff. in it's day

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on June 18, 2022, 05:02:28 PM
Now this was motivational!    I get to print what ever I want at work....could have done this in H13 tool steel.....but it's just for checking fits and my sanity....which always needs checking....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on June 18, 2022, 06:30:44 PM
Hi Dave,

That looks mighty impressive. If you could print it in aluminium; it would save you a lot of time and work filling those buckets with them tiny little chips.

Cheers

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on June 18, 2022, 09:17:18 PM
Good to see the crank in situ (so to speak)  :ThumbsUp:

Some things would be so much easier if we 'could just print them in the correct material'  ;D

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on June 19, 2022, 02:53:49 PM
Hi Dave,

That looks mighty impressive. If you could print it in aluminium; it would save you a lot of time and work filling those buckets with them tiny little chips.

Cheers

Mike

One material that we CANT print in    Aluminum...to say nothing of Magnesium....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on June 19, 2022, 11:12:19 PM
Hi Dave,

That looks mighty impressive. If you could print it in aluminium; it would save you a lot of time and work filling those buckets with them tiny little chips.

Cheers

Mike

One material that we CANT print in    Aluminum...to say nothing of Magnesium....
If you can print in chocolate chip cookie dough, I got some business for you!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 17, 2022, 01:29:54 AM
Been away on other stuff!     But    I'm baaaaack!

Setting up to carve me some con rods....programming is done as is the set up for the first 2 operations.  ( of 4)

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 17, 2022, 02:19:07 AM
More to come.......tomorrow.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: cnr6400 on October 17, 2022, 04:53:14 AM
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:

chips'll be flyin soon!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on October 17, 2022, 09:27:09 AM
Glad to see you back on this  :ThumbsUp:  :ThumbsUp:  :wine1:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 17, 2022, 02:38:50 PM
Well   the weather is changing so back in the shop and packing up the boat for the season..
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Johnmcc69 on October 17, 2022, 08:30:18 PM
I was just wondering where you've been. I know, life gets in the way of our more pleasurable pursuits...

 Nice work Dave! I hope everything is going well for you & the family.

 John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 17, 2022, 11:35:23 PM
thanks for checking in everyone, John, while the weather was good I was working on my boat repower project...made lots of progress there

But now winter is here...so back in the shop

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on October 18, 2022, 12:02:39 AM
Terrific boat!!  Spring wil be here again soon (I hope!)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on October 18, 2022, 12:40:52 AM
That's beautiful, Dave!
That first pic must be before the diesel transplant that you're working on?  Back when she was a steamer? :)

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 18, 2022, 10:49:32 AM
That's beautiful, Dave!
That first pic must be before the diesel transplant that you're working on?  Back when she was a steamer? :)

Kim

Yeah.   Mama loves her but is tired of sitting in the firewood...    "Rushforth's" new job is to provide transportation from one bed a breakfast to the next.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 23, 2022, 11:54:59 PM
So I'm working on the connecting rods, and currently tooling up.    I'm going to need 3 reamers.   The connecting rod big end bore,   the little end bore, and the bearing shell bore.....that works out to about $100 for a set of decent reamers!!!     That said, I took another approach, and I made tool makers reamers.     I started with HSS drill blanks that are very cheap.   They're only good for about .002-.005" material removal, but they works well, and are cheap      I've gotten a few sizes and roughed them down, next I'll try a few holes and see how the sizing goes and which one works the best...but for about $15 plus shipping, Ive got some choices.....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on October 24, 2022, 11:00:49 AM
I know about a D-Bit Reamer used for high precission and often very deep bores ....

But I must admit to not know how to use a Toolmakers Reamer ..??

Is it self starting or do you need to have a pilot hole first ?

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 24, 2022, 02:08:39 PM
Yes the hole needs Tobe close to size to work correctly.   It's just for sizing.   

I don't trust the circular interpolation on my mill to better than .0005" and I want these holes round.   

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 07, 2022, 02:00:30 AM
A test cut consisting of a a circular interpolated hole to 0.391, and followed up with a hand made 10mm reamer.    Could stand to have the cutting face stoned a bit.. but it cuts dead to size....sorry that's all I could get to these last couple of weeks between work and the honey do list.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: petertha on November 07, 2022, 02:21:11 AM
I've been meaning to try a reamer like that. Is there some rule of thumb on the facet like Angle of X-degrees viewed from side or span across 5-ish diameters or...?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 07, 2022, 02:31:02 AM
I've been meaning to try a reamer like that. Is there some rule of thumb on the facet like Angle of X-degrees viewed from side or span across 5-ish diameters or...?

The angle is not that critical.   30 degrees is fine.. It's important to stone the face flat, so that you can polish it with a stone.

It's good for .002" to .005" stock removal.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 12, 2022, 03:56:42 PM
And so it begins!!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on November 12, 2022, 04:51:53 PM
Ooh!  Guys, pass that popcorn!   :popcorn: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on November 12, 2022, 05:00:04 PM
Let the chips fly.  :cartwheel:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 12, 2022, 10:10:51 PM
First op is done!    That included some setup.  I also had to take advantage of the weather and do some maintenance on my daily driver.     I'll finish them off tomorrow!  ( 3 more ops)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on November 12, 2022, 10:33:13 PM
Looks like two spares/test pieces? There is a LOT of work in all those compartments!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 12, 2022, 10:36:11 PM
Looks like two spares/test pieces? There is a LOT of work in all those compartments!

Yes there is!   and it dpesn't show any of the fixtures for holding.    I get to make another one tomorrow!...

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Brendon M on November 12, 2022, 10:45:58 PM
Looks great :)

Just looking at all those parts is giving me an appreciation for CNC; I am not sure how my sanity will cope when I start on multi-cylinder engines with the "Count Number of Cranks" method  :toilet_claw:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 12, 2022, 10:48:25 PM
Looks great :)

Just looking at all those parts is giving me an appreciation for CNC; I am not sure how my sanity will cope when I start on multi-cylinder engines with the "Count Number of Cranks" method  :toilet_claw:

All the crank parts were finished in the manual lathe, without a DRO.....It's doable for sure...just takes longer, and you need to be more careful with measurements.

Dave

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 13, 2022, 07:50:44 PM
Op 2 complete!     Now I need to make a fixture that will locate the rods by their holes so I can profile the part from both sides   (Op 3 & 4)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on November 13, 2022, 07:55:40 PM
Jigs are well worth the time!

What metal are the con rods made from?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 13, 2022, 08:06:15 PM
Jigs are well worth the time!

What metal are the con rods made from?

7075-T6 Aluminum with grade 8 hardware.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on November 13, 2022, 08:45:57 PM
Jigs are well worth the time!

What metal are the con rods made from?

7075-T6 Aluminum with grade 8 hardware.

Lots of nice shiny metal there Dave. 

+1 for using machining jigs or fixtures for repetitive work

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 13, 2022, 09:24:48 PM
Jigs are well worth the time!

What metal are the con rods made from?

7075-T6 Aluminum with grade 8 hardware.

Lots of nice shiny metal there Dave. 

+1 for using machining jigs or fixtures for repetitive work

Mike

Thanks for looking in everybody!   Yup   I have a bit of stock up there now, and I need to drill and bore two holes to screw the rod down to, then the next two operations are the easy ones,  also the most time consuming cycle wise....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 13, 2022, 10:27:01 PM
OK    nice simple fixture using toolpaths that already exist with the part, and I'm all set.   I need to tap two holes, and make up some bushings to match the conrods, and I'm on to op 3 and 4.

I got a honey do first.... 8)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 14, 2022, 01:48:25 AM
There.   Alignment bushings made    ....and I'm out of M3 screws!...   tomorrow...
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on November 14, 2022, 11:10:16 AM
Great to see that you are making Real Progress again Dave - must feel good  :LittleAngel:

I will continue to follow with very great interest  :Love:

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on November 14, 2022, 05:41:19 PM
Great to see you getting some shop time, Dave!  And wonderful progress on your fleet of conrods!  :popcorn: :popcorn:

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 20, 2022, 03:25:58 PM
an interesting thread over in the "Vixens Den" on the Merc.   What an awesome build! 

I had several concepts for the crankshaft for this engine, mostly based on Shillings' designs, and concepts applied to the very unique 917 crank shaft     One problem I had was that there was no real room to get a big enough ball/roller bearing from the perspective of radial load anyway, into the space available with the 917 crankcase.   The rod bearings needed to be thinner like the prototype plain bearing shell system.   Meanwhile, I did not fancy trying to turn/ mill a crankshaft with cross drilled oil delivery for the main bearings, and as commercial hobby model aircraft and car engines do run quite reliably with plain bronze bearings, I went with ball bearing mains, and plain bearing conrod bearings, a hybrid, that should be very forgiving of almost any form of lubrication.     

For a multicylinder engine, I honestly think the shilling style of crankshaft is a sound way forward.

Below are two of the designs I had for the 917 engine, based on Shilling, but in the end, I went with a plain bearing rod/ball bearing mains solution in the second photo, which was documented here.  What makes the 917 engine unique is the power being taken off the center gear of the crankshaft, not at the ends.   

Back to conrods....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on November 20, 2022, 03:41:37 PM
Another major advantage of a plain bearing conrod is it gives you the choice of a bolted, split, big end bearing or a solid one piece conrod. It can also halve the number of pieces that need to be bolted together to form the crankshaft. With a roller bearing conrod, you have no such choice.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 20, 2022, 03:52:00 PM
Another major advantage of a plain bearing conrod is it gives you the choice of a bolted, split, big end bearing or a solid one piece conrod. It can also halve the number of pieces that need to be bolted together to form the crankshaft. With a roller bearing conrod, you have no such choice.

Mike

Quite right Mike, it's fortuitous that you could get your crank put together "In prototypical fashion".  There is much to be said for ball/roller bearings as they are going to be far less sensitive to quantity and quality of lubrication as well.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on November 20, 2022, 04:29:38 PM
Quote
Quite right Mike, it's fortuitous that you could get your crank put together "In prototypical fashion".

The era of the prototypes has a lot to do with that.
In 1938/39, roller bearing conrods was the only reliable way to build a high revving (8000RPM) racing engine. By 1969 'thin wall' plain bearing had come of age and engine designers could make full use them to build much more compact engines, like the 917. Also the rapid improvements to lube oils, aided the transition to plain bearings.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 20, 2022, 05:13:13 PM
First side of the 14 rods   Op 3/ side 1
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 20, 2022, 05:32:42 PM


https://youtube.com/shorts/HHi0IMWwJcM?feature=share

First side  Op 3
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: petertha on November 20, 2022, 06:38:24 PM
...an interesting thread over in the "Vixens Den" on the Merc.   What an awesome build! 
... I had several concepts for the crankshaft for this engine, mostly based on Shillings' designs, and concepts applied to the very unique 917 crank shaft..

You guys are doing some fine work! More questions.
I noticed on the Schillings CS, the bearing OD (red) is larger than the counterweight segment OD (green). I was never really clear on this. Was the idea to provide ability to slide CS in/out of a matching crankcase bore? He also half grooved a recess in the counterweight segments to accommodate the bearing ID. I was trying to visualize this in real life. Sliding in a multi bearing assembly into a close fitting hole would be challenging enough, but if it was even a bit un-axial via each segment fit, maybe more challenging yet. Or maybe that was the magic of the method, the CS assembly self straightened as it was inserted?

Anyway, I noticed on your CS, the throw OD is larger than the bearing OD, so you just bore the supporting bearing support webs & throw clearance ID accordingly. Your CS layout seems simpler to my simple mind. But I assume this layout could only be accommodated with a split style crankcase whereas Schillings is a mono block? Maybe I'm completely out to lunch here. hanks for any guidance.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 20, 2022, 07:11:51 PM
...an interesting thread over in the "Vixens Den" on the Merc.   What an awesome build! 
... I had several concepts for the crankshaft for this engine, mostly based on Shillings' designs, and concepts applied to the very unique 917 crank shaft..

You guys are doing some fine work! More questions.
I noticed on the Schillings CS, the bearing OD (red) is larger than the counterweight segment OD (green). I was never really clear on this. Was the idea to provide ability to slide CS in/out of a matching crankcase bore? He also half grooved a recess in the counterweight segments to accommodate the bearing ID. I was trying to visualize this in real life. Sliding in a multi bearing assembly into a close fitting hole would be challenging enough, but if it was even a bit un-axial via each segment fit, maybe more challenging yet. Or maybe that was the magic of the method, the CS assembly self straightened as it was inserted?

Anyway, I noticed on your CS, the throw OD is larger than the bearing OD, so you just bore the supporting bearing support webs & throw clearance ID accordingly. Your CS layout seems simpler to my simple mind. But I assume this layout could only be accommodated with a split style crankcase whereas Schillings is a mono block? Maybe I'm completely out to lunch here. hanks for any guidance.

My crank case is split down the middle, and the center two main bearings are flanged and take all the axial thrust on the crank

Here is a cut away of the crank I have and as you can see, it is constructed of seperate throws and cheeks where the main bearing is spigot.ed and clamped between with 3 M4 screws  on each side of the crank segment.   The drive gear is in the middle of the crank as a seperate part

Each crank section consists of 2 cheeks and a crank pin and are press fit together.    You finish 1 crank cheek to fit the bearing, and leave the other one with stock to remove.    Then you mount the raw crank section in a fixture in the lathe by the finished side, and then turn the other crank cheek insitu to finish diameter and shoulder depth.   By doing it this way, the bearing diameters are always dead concentric.     then building the crank from these sections is as easy as bolting it all together.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on November 20, 2022, 07:47:17 PM
Great looking Crankshaft and Conrod Dave  :praise2:

I can't open the video  :'(

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 20, 2022, 07:49:53 PM
Yeah I can't open it either, but it opens on my Youtube page..... :noidea:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jasonb on November 20, 2022, 07:58:56 PM
Is it set to private?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on November 20, 2022, 08:05:13 PM
Dave,
It looks like your video was made a 'short' by YouTube.  I've had a LOT of problems with those 'shorts'.  Anytime you have a YouTube link that has that word 'shorts' in it (like yours does) you can't link to it.  I don't know why (at least, not in this forum).

I've struggled with that 'shorts' thing since they introduced it a while back.  At first, I was very confused.  It just seemed random. But apparently, any video that's short (less than 30 seconds?  or maybe 60 seconds?) and that's recorded in portrait mode with a phone is automatically made a 'short'.  And there's nothing you can do about it.  I've struggled with it.  Sometimes it will drop off the 'shorts' list in a few hours or a day and then you can post it.

The thing that seems to work best for me is to record the video with my camera - those videos never seem to become shorts.  It's only the phone videos.  I also believe if you record your video in landscape mode it won't be co-opted by the 'shorts' thing.

I'm sure shorts are a great thing. But they don't work for anyone trying to post the video to this forum!  :'(

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jasonb on November 20, 2022, 08:10:33 PM
Peter, Schillings usually had a horizontal split in his crankcases, vertical on the boxer though the straight six did have caps over each bearing
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 20, 2022, 08:14:24 PM
Is it set to private?

No I have it shared on Facebook....so shouldn't be   I chose public
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jasonb on November 20, 2022, 08:24:04 PM
Found it, as Kim says it's a Short. Hold your phone in landscape next time which is better for PC and tablet screens anyway.

video (https://www.youtube.com/shorts/HHi0IMWwJcM)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 21, 2022, 02:11:02 AM
14 connecting rods done! 12+2 spares, and I didn't scrap a single one! Onward! time to make some bearing shells to fit the crankshaft laying along side all these rods.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on November 21, 2022, 02:24:44 AM
What a fantastic little toy box! You and Mike (Vixen) certainly set a high bar! :ThumbsUp: :ThumbsUp: :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 21, 2022, 02:58:23 AM
What a fantastic little toy box! You and Mike (Vixen) certainly set a high bar! :ThumbsUp: :ThumbsUp: :cheers:

I'm not even in the same zip code as Mike..... :AllHailTheKing:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on November 22, 2022, 07:13:04 PM
That's a fine collection of parts  :praise2:  :praise2:

You can beat the short thing on YouTube if you copy the link as soon as you start to upload before it gets changed to a short format. This link will work on the Forum.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 25, 2022, 03:22:06 PM
Thanks for looking in everyone    next on the agenda is rod bearings.   I'll need to make 24 bearing halves  mostly on the lathe    we got off to a bad start yesterday fora bunch of different reasons so we're having our Thanksgiving today instead but maybe later today I'll get into it.  Mostly lathe work I think..
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 26, 2022, 01:40:20 AM
All set for first and second op tomorrow...
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on November 27, 2022, 01:43:12 AM
Op 1 of the rod bearings nears completion.   24 bushes make 24 bearing shells, 2 for each connecting rod,   Next step is to cut these exactly in half and then reassemble in a fixture and bore to final size.

Bearing OD and the width are pretty critical, and I'm trying to hold+/- .0005" on the bearing diameter.   This is not that bad if I leave the tool holder in the tool post, but repeatability of my chinease AXA wedge type is about is more like +/- .001" at best.....maybe time for a genuine Aloris!

Dave
 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 03, 2022, 11:22:23 PM
OK   I've been sick for a week.   The flu...NOT covid....but I'll tell you   It kicked my ass!

I've been non functional since last Sunday...I missed work....and stayed in bed......so

Today...I felt much better.....finally....though I'm still in a fog

I was able to get 30 bearing shells complete, and a first pass at the fixture to split them.   I'm stopping there
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on December 03, 2022, 11:31:34 PM
30 bearing shells is nothing to sneeze at Dave!  That's a lot of work there.

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on December 04, 2022, 12:31:11 AM
Glad you are feeling better!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 04, 2022, 01:43:34 AM
Thanks guys.    Well   it was a false start, as I'll need to redo the fixture just a touch.   The idea is to grab a shell blank in the vise, as shown in the picture just below the center of the bearing diameter shown above as a bushing, while in the fixture which will locate it.   First operation is to machine half of it off.  Second is to drill a hole exactly in the middle of it.   This hole is a retaining pin hole for the rod side, and a lubrication hole for the cap side.   It needs to be cut right on the flys back side down the middle, so that the cap will have enough grip.       This should be a challenge for sure!!  Which is why I made a bunch!    I need 14 pairs...so I get to screw up a few in the process .......Tomorrow though!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on December 04, 2022, 10:47:48 AM
No fun, no matter what Virus that floors you  :-\  ..... glad you are felling better  :)

I agree with Kim - 30 bushings on your rebound is nothing to sneeze at  :cheers:

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on December 04, 2022, 08:50:17 PM
OK   I've been sick for a week.   The flu...NOT covid....but I'll tell you   It kicked my ass!

'Man flu'....... that's the worst kind  :censored: :censored:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 04, 2022, 09:09:49 PM
OK   I've been sick for a week.   The flu...NOT covid....but I'll tell you   It kicked my ass!

'Man flu'....... that's the worst kind  :censored: :censored:

Mike
I can't remember the last time I was layed out for.a full week....not good
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Art K on December 05, 2022, 07:54:54 PM
Dave,
On vacation, it's good to sit down and have the time to get cought up with your build. One question, how much of a gap between the two halves of each throw? I am following that the bearing in between locates the faces. Presumably the gap doesn't matter so much. I do have a pdf of the Schilling book but "mein Deutch ist sehr schleckt" is there an English version available? Wonderful work!
Art
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 05, 2022, 08:23:51 PM
Dave,
On vacation, it's good to sit down and have the time to get cought up with your build. One question, how much of a gap between the two halves of each throw? I am following that the bearing in between locates the faces. Presumably the gap doesn't matter so much. I do have a pdf of the Schilling book but "mein Deutch ist sehr schleckt" is there an English version available? Wonderful work!
Art

Im shooting for an .0005 interference fit.   :ROFL:  As a bush it is that, and the caps close up completely, and the bush is immobile.         That's the target anyway....we will see.
the fixture is going to be a key component in this operation, splitting these bushes exactly in half is what Im going to try to do.     Then I'll need a fixture to hold them for final boring and finally reaming while clamped.....it's going to be tedious at best!     this is pushing me to a level of consistency that I'm not sure I can do....but I will try...and the only down side of trying is scrapping some bronze bushes....so the risk is pretty low.....comparitively.

And no I don't know of an English version of this book, though Mike and I have had some luck using the Google translator.  At the end of the day, the drawings speak pretty well for themselves.
Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Art K on December 05, 2022, 09:01:45 PM
Thanks!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 06, 2022, 02:19:12 AM
First pair fit perfect!    On to the rest
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on December 06, 2022, 02:25:04 AM
YeeHaw!! Lookin' great, Dave.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on December 06, 2022, 02:43:06 AM
Beautiful!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 06, 2022, 05:30:14 AM
15 pairs of bearing shells up to op2.  They need to be drilled....but not tonight.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on December 06, 2022, 11:30:10 AM
Looking good  :praise2: Are you going to finaly ream the bores when they are assembled or are the production tolerances tight enough?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on December 06, 2022, 12:16:57 PM
15 pairs of bearing shells up to op2.  They need to be drilled....but not tonight.

15 pairs of half bearing shells from 30 complete bearing rings :praise2:      Well done, you have not lost any yet :praise2:

But you must have got through a whole lot of bar stock and made a mountain of shiny chips. Shame you cannot find a use for the undersize half of the bearing shells.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 06, 2022, 01:01:10 PM
Oh far from
Killed 3 on op1
Killed 4 on op 2
Had to make more last night to get 15
Went through 18" of 1/2 " bronze bar.
And I still have more ops to do!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 06, 2022, 02:43:09 PM
Looking good  :praise2: Are you going to finaly ream the bores when they are assembled or are the production tolerances tight enough?

I'm building a locating fixture to bore and then ream to final size.   

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on December 09, 2022, 09:27:44 AM
Dave - this typ.912 engine is one of my favourite engineering designs.
Really enjoying the way your going about this build and documenting and sharing it.
Regards
John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 09, 2022, 04:03:18 PM
Dave - this typ.912 engine is one of my favourite engineering designs.
Really enjoying the way your going about this build and documenting and sharing it.
Regards
John

Thank you John,   Im trying     The machining challenges of this engine are pretty epic to me.    I rarely have to do 12 of anything, and making 12 exactly alike...or as close as I can get....has been a real challenge to me    It's upping my game for sure!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 09, 2022, 04:26:17 PM
Oh far from
Killed 3 on op1
Killed 4 on op 2
Had to make more last night to get 15
Went through 18" of 1/2 " bronze bar.
And I still have more ops to do!

Dave

Dave - this typ.912 engine is one of my favourite engineering designs.
Really enjoying the way your going about this build and documenting and sharing it.
Regards
John

Thank you John,   Im trying     The machining challenges of this engine are pretty epic to me.    I rarely have to do 12 of anything, and making 12 exactly alike...or as close as I can get....has been a real challenge to me    It's upping my game for sure!

Dave

Observations on my mill while making these bearings.   After the 4th bearing I noticed that the fixture was being rubbed by the cutter during the cut....the first 4 did not do that    I checked for chips under the fixture, but I didn't find any, and it was starting to cut bad parts....hmmm

The cutter was in it's holder tight, and I wasn't removing the tool holder between parts, and the tool was taking a .010" facing cut in bronze.....so it was very unlikely I was pulling the cutter out...and the amount was very small....  I checked the cutter and it wasn't worn.    OK...so the machine tool Engineer in me screamed "Thermals"

The only coolant on the machine is mist lube ( compressed air/mist) and as it was bronze i wasn't using it.    As the spindle was running at 4000 rpm, and it was a couple of minutes long cycle,   I suspected that the spindle nose/toolholder were warming up and growing in length......   

So I added coolant to the program, and I aimed the air jet at the middle of the tool holder.      Let it sit for a minute or 2 and tried again but now with coolant on.

It immediately started to behave like the first cut!    Ha ha!   so I then cut the rest of the 30 parts that way  ( 38 or so in total including the scrap ones.)  and the tolerance was +/- .0005' which considering it's not a precision mill by any means,  was pretty good!!!

Just some of the things you run into when you're running "production"...which is something I rarely do.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on December 09, 2022, 04:42:49 PM
Hello Dave,

"Thermals"..... Yes, they can be a problem with repetitive work. It's one of the reasons I do little machine shop work during the winter months. The machinery is my unheated outside workshop can get very cold overnight. If I put the fan heater on to get the shop warm enough to work in, the machines get a thermal shock, slowly start to warm and expand. Any ideas about maintaining tight tolerances go out the window.

Mike   :atcomputer:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 09, 2022, 04:47:42 PM
Hello Dave,

"Thermals"..... Yes, they can be a problem with repetitive work. It's one of the reasons I do little machine shop work during the winter months. The machinery is my unheated outside workshop can get very cold overnight. If I put the fan heater on to get the shop warm enough to work in, the machines get a thermal shock, slowly start to warm and expand. Any ideas about maintaining tight tolerances go out the window.

Mike   :atcomputer:

Luckily for me my shop is heated, and in future, I'll let the spindle run for an hour before I touch off in future.  Between that and the machine enclosure, it should be isolated enough to perform well enough.  It's cold outside for about 7 months out of the year around here.....gotta deal with it somehow.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 14, 2022, 01:31:13 AM
A bit more this past weekend.   got the drill, bore and face fixture complete.    and I drilled and bored 1 set of bearings for a trial.   Pretty good!   About .0005" as far as I can tell.    It was interpolated, and I think I'll ream it ultimately instead.    It was a great exercise though!    Back at it this weekend with a reamer this time.
 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on December 14, 2022, 02:27:17 PM
Always great to confirm that you got it right - feels good + looks good to the rest of us  :ThumbsUp:

Per          :cheers:

ps    interesting reminder about Thermals in the previous posts
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on December 14, 2022, 04:43:33 PM
Very nice, Dave!

I drilled and bored 1 set of bearings for a trial.   Pretty good!   About .0005" as far as I can tell.    It was interpolated, and I think I'll ream it ultimately instead.    It was a great exercise though!    Back at it this weekend with a reamer this time.
So, I thought you were supposed to drill, bore AND ream for maximum accuracy of your hole?  Drill to remove most of the material bore to make sure the hole is STRAIGHT, then ream to get an accurate diameter.

Is it just not worth boring on a hole this short?

Kim "Curios minds want to understand"

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 14, 2022, 04:59:39 PM
I'm going g to bore with circular interpolation and then ream for roundness and size     I wanted to know if I could get away with interpolation    but I don't think I can.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 14, 2022, 05:54:47 PM
And when I day interpolation  I mean circular interpolation
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on December 14, 2022, 05:59:19 PM
By circular interpolation, I assume you mean getting the CNC to machine a circular hole, instead of using a boring head.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 14, 2022, 06:12:23 PM
By circular interpolation, I assume you mean getting the CNC to machine a circular hole, instead of using a boring head.

Mike

Correct    I don't think it will be round enough at least with my machine
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 14, 2022, 07:14:56 PM
Modern machinery with good screws or linear motors   sure it can....but not with my tinkertoy.....saying that...as I am the master of my shop   I get to try whatever I like..

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on December 14, 2022, 07:16:04 PM
By circular interpolation, I assume you mean getting the CNC to machine a circular hole, instead of using a boring head.

Mike

Correct    I don't think it will be round enough at least with my machine

Hello Dave,

My question was intended to explain what circular interpolation was, to those with little or no CNC background

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 14, 2022, 07:30:31 PM
By circular interpolation, I assume you mean getting the CNC to machine a circular hole, instead of using a boring head.

Mike

Correct    I don't think it will be round enough at least with my machine

Hello Dave,

My question was intended to explain what circular interpolation was, to those with little or no CNC background

Mike
Understood.    I should have more clear.   I'm using it in place of boring prior to reaming.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on December 15, 2022, 01:11:35 AM
Ah... OK.  Makes perfect sense!  Thanks for the excellent explanation.  Now I'm smarter than I was 3 minutes ago!   ^-^

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 15, 2022, 01:22:08 AM
Well that makes you smarter than me!

Love that boiler Kim!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on December 15, 2022, 01:41:48 AM
Well that makes you smarter than me!
Yeah, right...  :???:

Love that boiler Kim!

Dave
Thanks Dave!  :cheers:
Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Diegovv on December 15, 2022, 01:38:53 PM
A bit more this past weekend.   got the drill, bore and face fixture complete.    and I drilled and bored 1 set of bearings for a trial.   Pretty good!   About .0005" as far as I can tell.    It was interpolated, and I think I'll ream it ultimately instead.    It was a great exercise though!    Back at it this weekend with a reamer this time.
 

Impressive job so far, congratulations, it will be a beautiful engine. One question that comes to my head is....How do you ensure that the conrod bronze busing doesn´t spin? Does it have any anti-rotation feature built into it so it registers in a fix position?

Thank you!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 15, 2022, 06:22:00 PM
Yes there is a pin on the rod side that I will be drilling in situ thru the cap  both bearing halves and the a bit into the rod.   The short pin goes on the rod side while the other side allows oil to enter.   The bearings are a slight interference fit as well.    So should be good to go.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on December 19, 2022, 03:28:27 AM
Hi Dave
I'm really enjoying reading your thread and absorbing your challenges, methods, jigs and ideas.
A question if I may regarding location of the conrod cap. It's not clear to me how (or if) you're locating it.
Is it dowelled at the joint, or by the rod bolts themselves?
Will the flange of the pinned bearing shell (bronze bushing) provide location of the cap (perhaps by some minor rotation of the shells within the rod prior to drilling and pinning) ?
Do the cap and rod meet at mating corrugated surfaces ?
Or is it not positively located by any method?
Apologies if I've missed a prior explanation.
Regards
John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 19, 2022, 05:44:58 AM
Hi Dave
I'm really enjoying reading your thread and absorbing your challenges, methods, jigs and ideas.
A question if I may regarding location of the conrod cap. It's not clear to me how (or if) you're locating it.
Is it dowelled at the joint, or by the rod bolts themselves?
Will the flange of the pinned bearing shell (bronze bushing) provide location of the cap (perhaps by some minor rotation of the shells within the rod prior to drilling and pinning) ?
Do the cap and rod meet at mating corrugated surfaces ?
Or is it not positively located by any method?
Apologies if I've missed a prior explanation.
Regards
John
Hi John,
Great Questions!

The pin for the bearing shells is just to prevent spinning the bearings,  The bearing OD's are a interference fit, slightly, but as added protection , I will be pinning the rod side bearing shell to the rod.    Side thrust on bearing shell is controlled by the flanges on the bearing inserts.   Now to your question about the caps

Prototypical conrods typically have bolt locating bushing or serragated faces...though the bushes are far more common.
All of the engine model plans that I've seen do not provide pins on the caps !    They do however show that the "clearance on the rod bolt is quite tight...as are mine, as the clearance hole for these screws in on the order of .002 or .003".   So that was the original plan

Shilling, Westbury ect.    Ron Colonna's Offy uses .020" pure silver liners and screws....No pin bushings.

Now ...I'm sitting in my shop last weekend, and I'm looking at this rod, and I'm wondering what else I could do to make sure the cap is well positioned, and the thought was to turn the bearing halves 15 degrees in the bore prior to drilling and pinning them,  so that the flanges cross over the joint....but I've not convinced myself that is necessary at this time,  though I could definitely do that!

The pin that I'll put in will make each bearing a dedicated bearing to that rod, and that is fine with me.  Regardless of whether or not I rotate the shells....so it doesn't matter as each bearing is a "fit" bearing.   

Right now I have my daughter in the hospital unexpectedly for the last 4 days, so its all on the back burner for a few days till we figure out whats going on...so although I really wanted to be out there this weekend...My daughter is obviously "Job 1"..

Dave


Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 19, 2022, 04:45:41 PM
Crude sketch....of what I'm on about John.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on December 19, 2022, 05:30:31 PM
Great progress on the bearings, and best wishes for your daughter! 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on December 19, 2022, 05:35:45 PM
Hope all is OK with your daughter. That's got to be very frightening to have one of your kids in the hospital. Praying for the best for your family!

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: vtsteam on December 19, 2022, 05:49:42 PM
I hope your daughter is okay, Dave.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 19, 2022, 08:33:19 PM
Thanks guys   I'm in hurry up and wait mode....they've been testing for over 4 days......it's not pleasant for her, or anyone else!

Hoping to hear something today.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on December 19, 2022, 10:17:28 PM
Hi Dave - hope all is well with your daughter.
Your description of the pinned flanged bearing shell and slight rotation (15°) for cap retention was exactly as I had in mind, brought to life by your CAD rendered image. (so far from a "crude sketch" !!!).
Regards
John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 19, 2022, 10:30:26 PM
Hi Dave - hope all is well with your daughter.
Your description of the pinned flanged bearing shell and slight rotation (15°) for cap retention was exactly as I had in mind, brought to life by your CAD rendered image. (so far from a "crude sketch" !!!).
Regards
John

Yeah I think it would work!     I've talked myself into it I think.   I'll post here.

She's coming home tonight!    :whoohoo:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 19, 2022, 10:45:23 PM
And as far as oil grooving, I'm only going to lightly chamfer the interface to let oil in.

No oil hole at the back....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on December 20, 2022, 12:16:09 AM
That's an interesting idea for cap alignment. I like it.
Quote
She's coming home tonight!
And that's great too!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: 90LX_Notch on December 20, 2022, 01:07:14 AM
My prayers are for your daughter.

-Bob
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on December 20, 2022, 01:56:26 AM
Dave -great news that your daughter is coming home!
I'm not sold on the idea of the chamfer at the bearing shell joint...at some point(s) in rotation the major load will be across that line on the bearing and you may lose the peak of hydrodynamic pressure, greatly lowering the load capacity of the bearing.
John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 20, 2022, 02:05:05 AM
Dave -great news that your daughter is coming home!
I'm not sold on the idea of the chamfer at the bearing shell joint...at some point(s) in rotation the major load will be across that line on the bearing and you may lose the peak of hydrodynamic pressure, greatly lowering the load capacity of the bearing.
John

Thanks John.   Peak load is during power stroke and will be on the rod side bearing, not the split.   Even if it's rotated 15 degrees, however, this bearing doesn't have an oil feed from the crank, it's coming from the outside...  so a VERY SMALL chamfer at the low pressure area of the bearing is not a bad choice....I can only ride a film of oil if the oil is there to begin with...

0.010" x 45 is what I'm thinking of. 

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 20, 2022, 02:21:34 AM
The reamer I'm going to use for the bearing is 0.0003" larger than the journal on a 0.2655" journal.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 20, 2022, 02:35:31 AM
And on another note,   I wont be running this at 247 MPH down the Mulsanne straight for 24 hours....just some demo runs for S an G's....Most commercial 4 stroke model aircraft engines run on oil added to the fuel that blows by the rings and THEN provides lubrication to the engine....I'll have a dedicated oil pump and scavenge pump, so I think she'll be alright.....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on December 20, 2022, 11:45:51 AM
And on another note,   I wont be running this at 247 MPH down the Mulsanne straight for 24 hours...
Dave

Ha, Ha!! That's because they have added two chicanes along the Mulsanne to slow the top speed of the cars. The LMP1  prototypes can now only reach 220MPH.  :lolb: But they are working on it.  >:D

Cheers   :cheers:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 20, 2022, 02:49:53 PM
And on another note,   I wont be running this at 247 MPH down the Mulsanne straight for 24 hours...
Dave

Ha, Ha!! That's because they have added two chicanes along the Mulsanne to slow the top speed of the cars. The LMP1  prototypes can now only reach 220MPH.  :lolb: But they are working on it.  >:D

Cheers   :cheers:

Mike

If it runs and has a nice V12 sound....with just a touch of gear whine....I'll be a very happy camper!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 01, 2023, 11:22:20 PM
The upper conrod bearing shells are now drilled and pinned.  The next step is bore and ream to final size.   The excess length of the bronze pins will be cleared away then.  I've done one just for kicks....it's tight, but it's a good tight...I'll be able to motor it and break it in eventually.  Tomorrow is another day though.....time to put it up, or I'll screw it up....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on January 02, 2023, 05:39:52 AM
That rod and bearing look mighty fine on your crank shaft there, Dave!  :popcorn:

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 02, 2023, 11:40:23 AM
Lots to do today on the honey do list but I'm sneaking out in the shop now to get a start

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 02, 2023, 02:48:24 PM
Got two bored and faced  fit nice too!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on January 02, 2023, 03:49:56 PM
Great - now you have the first Pair ready  :whoohoo:

I've been meaning to ask you why you choose to make the Bearing Shells that way you did Dave.
Why 'wasting so much metal' instead of for instance solder two flat blocks together and the turn them in the lathe ?

I can see the possible problem with 'leftover solder' - but you choose to all the final work after they where two halves anyway ....  :noidea:

Inquiring minds wants to know  ;)

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 02, 2023, 04:58:14 PM
Great - now you have the first Pair ready  :whoohoo:

I've been meaning to ask you why you choose to make the Bearing Shells that way you did Dave.
Why 'wasting so much metal' instead of for instance solder two flat blocks together and the turn them in the lathe ?

I can see the possible problem with 'leftover solder' - but you choose to all the final work after they where two halves anyway ....  :noidea:

Inquiring minds wants to know  ;)

Per

Per,
Good question!   So this engine is at 8.5 to 1 compression and running methanol.  The conrod bearings need to be well fit and stable.  I think we agree on that.

With the solder method, One usually has two blocks,  with at least 1 face each dead flat.    One of the two is longer so that you have a reference for where the center of the split is.
But do you really know?

As you pointed out, they are usually soft soldered together and then machined.  Once done with machining,  OD turned for a .0005" interferance fit, the bore set for .0005" clearance on the journal, and the width +/- .001, and flat,   what is now holding the two bearings halves together?   I think you can agree that if it comes apart before you're done the parts are wasted,  and you still need to cut off the long edge of one of the blocks, which is wasted material, on the order of what I lose machining half off.

To be honest the only surfaces that still have solder on them at this point is the joint face.      How thick is this layer of solder?   .0005"  .001" ?   Where is the center?
What happens to the fit of the bearing after you melt the solder

if my tolerance is .0005"   I'm done with the solder method.  It won't work.     With the method I chose, it's tedious, and stressful, but I get exactly what I was after.   And at the moment, You can't even see the joint under magnification.

Don't get me wrong, lots of engines get built that way, and for most steam engines , with 1 conrod, you can muck about and make it fit.   I didn't want that at all with 12 of them.

It comes apart and goes back together, something you do a lot of building a model engine.  No shims, no filing, no mucking about.  Every bearing feels the same and has the same clearance.

That's why I made the conscious decision to do it this way.    I suspect I may have "burned up" about a 6" long piece of bronze that didn't become a bearing.....I can live with that.

Dave


Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on January 02, 2023, 08:14:48 PM
Thank you very much for the explanaition Dave :ThumbsUp:

I think I got some of them right before - but you clarified them all very well (including those I didn't think of)  :cheers:

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 02, 2023, 10:47:54 PM
I'm sure there are lots of ways to get it done.   Much will depend on what you have for equipment, what experience you have.    This is the best way I know how with the equipment I have.  I will say this.   Doing the bearings, most of which was in the lathe, would have been much harder without my new DRO.  Its not that fancy a DRO, but it sure helps when your trying desperately to split a thou repeatedly.  I am very glad I got that and put it on!.      What would I have done without it?   I would have had to set a tenths dial test indicator on my cross-slide.    it would have added a great deal of time mucking around with zeroing it, reseting a cut, rezeroing, and checking.   All that needed to be done, but rezeroing with a dial indicator stand is tedious and delicate to any vibration.   The DRO rezero was a button push away.

Here's the finished bearing installed in Rod #1.   No split visible.  Note the oil slots on the cheeks, that is how I'm going to feed these bearings, as the cheeks are up against each other, there will be a little bit of pumping action there.   Each throw of the crank with two rods will have a oil nozzle feeding oil and a dry sump for return.    As most of these big model engines such as Schilling are lubricated  by oil in the fuel and planned blowby, the amount of oil required is not high, but it needs to be there!   I suspect this will work just fine.

After I cook some steaks for the crew, I'll get back on this and finish the remaining rods...  Next view will be a family portrait of a bunch of conrods on the crank!


Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on January 02, 2023, 11:24:04 PM
Lovely work Dave. The split bearing with pin and slight rotation of the shells looks to have achieved all of your goals with this assembly.
Regards
John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 02, 2023, 11:34:32 PM
So far it has!    knocking on any piece of wood I can find!     This was almost as hard as the crank!   

Next BIG challenge will be the cylinders with all the cooling fins...

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 03, 2023, 12:02:28 AM
Hello Dave,

When I built my two Bristol mercury engines; there were lots of fins to be cut in the aluminium cylinder heads and also around the steel cylinders. This is how I did it. Hopefully it will give you some ideas for you to consider for the Porsche.


"Next was the nail biting moment. Deep fins had to be cut around the base of the cylinder head and also fore and aft in the upper half. I mounted each cylinder head on a dummy cylinder, again located in my faithful old rotary table. I made up a gang of seven slitting saws to cut slots 35 thou wide with 25 thou spacers in between. The 7 slitting saws were selected  from a collection of ten saws, each of the same nominal width. It is amazing how good the human eye is at spotting a saw which cuts a slightly wider than the others.

The gang of slitting saws was plunged full depth into the cylinder blocks and the head slowly rotated on the rotary table until the fin slots were cut full circle. The fins look so delicate, with disaster about to happen at any moment; but in reality the saws are cutting into a solid lump of high quality material, the delicate fins see no cutting forces and are merely being left behind. The biggest issue was chip clearance. I ended up using the biggest available suds pump, surrounded by a jury rigged tin plate dam to try to contain the resultant spray. The spray of suds (stinking stuff) went everywhere.

(https://lister-engine.com/coppermine/albums/userpics/10013/HEAD21~0.jpg)


Here you can see cylinder head #5 of 20 being held in the machine vice for the fore/ aft fins to be cut. The cut was 0.75" (19.0mm) deep at the front and rear of each cylinder head. Note the comb block inserted between the horizontal fins, it holds the cylinder head firmly in the machine vice without marking or damaging the head.

(https://lister-engine.com/coppermine/albums/userpics/10013/HEAD23~0.jpg)

All this fin cutting was done on my old Dore Westbury mill using the hand wheels. The spindle was direct belt drive from the single speed motor, giving about 200 RPM at the spindle when using the lowest belt ratio. Low ratio belt gearing increases the torque at the spindle, which you will not get with a VFD speed reducer.


The result of a full year's nail biting work lined up on parade. The result, 18 near perfect cylinder heads, one reasonable one for use as a spare and only one casualty, which was partially sectioned to check on remaining wall thicknesses under the fins.

(https://lister-engine.com/coppermine/albums/userpics/10013/HEAD25.jpg)



Hope this will be of some help

Cheers   :cheers:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2023, 12:21:12 AM
Thanks Mike.   the issue is going to be HP.   While I bet your mill has a back gear, and some Clydesdale HP....I only have the Gerbil kind!    My low speed is via a belt change and at that point it's in the basement at 300 rpm.   at that point I bet I could stop it with my hands. I'm not worried about the motor per say, but I am worried about the VFD drive for that motor.  I was able to get a 32 DP cutter through steel at 1 inch per min feed rate at 300 rpm...just....so a cut took a while!  I don't think I can gang the saws like that and make it....but I can spin a carbide saw at 1100 rpm    8)    So that's what I'm going to try...with some mist lube to get the chips out of the cut zone....

Working with what I got....  The bigger issue is currently, the cylinders are 1144 steel and not aluminum....but I'm considering a change..if for no other reason than making it easier on my mill to cut the fins.   I would then have to run sleeves...of some form, probably cast iron with the outer fin unit shrunk on.
I don't think I'd have a problem with ganging the saws if I can run at oh 2000 rpm in Lo range....then I know I won't load up the drive to much.  that and finding a pair to hit the cycle start button on that set up   :toilet_claw: :stickpoke:


Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on January 03, 2023, 01:11:18 AM
Quote
Here's the finished bearing installed in Rod #1.   No split visible.
If I didn't know better I'd swear those bearings are one piece. Very impressive work, Dave!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2023, 01:35:14 AM
Thanks RReid...With the rod cap loose.    Angle on the split is fixed and intentional

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2023, 03:53:54 AM
Conrods Done!    Family portrait time.....starting to hint like it's part of an engine!

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on January 03, 2023, 04:07:00 AM
Now THAT is a great looking family!   :ThumbsUp:   :popcorn:   :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2023, 04:13:01 AM
YUP   it goes in spurts....you work on a set of parts for ever, and then all of a sudden BANG!   I moved the needle a little...

 :lolb:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on January 03, 2023, 04:46:06 AM
That's a lot of parts there!  A lot of work and a ton of planning went into that family!  :ThumbsUp: :popcorn:
Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on January 03, 2023, 08:46:30 AM
Splendid work  :praise2:  :praise2:  :wine1:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on January 03, 2023, 11:09:43 AM
Now that is a Major Milestone  :ThumbsUp: and it looks like the Magnificient Familly is ready to Rock 'n' Roll  :cartwheel:

Impressive work Dave - and I'm sure you're Very Happy to have finished this essential part of the Engine  :cheers:

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2023, 12:30:21 PM
https://www.youtube.com/shorts/erulLZQaJzI

Sanity check
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on January 03, 2023, 02:56:32 PM
Congratulations Dave! It's all downhill from here, right? (Yeah, right). :cartwheel: :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2023, 05:30:51 PM
Congratulations Dave! It's all downhill from here, right? (Yeah, right). :cartwheel: :cheers:

The cylinders have me chewing my nails at the moment....lots and lots of fins....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: vtsteam on January 03, 2023, 07:20:50 PM
Looks fabulous!  :ThumbsUp: :ThumbsUp: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on January 03, 2023, 09:22:57 PM
Looks like its really coming together Dave.
Have you considered applied aluminium fins on DOM steel tube for cylinders?
Punch, press fit then clean up on the lathe and mill.
Regards
John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 03, 2023, 11:40:51 PM
The cylinder body is more complicated than that as it forms the mount for the individual cylinder head x6 which is the base for a 1 piece DOHC cam box.....    So it would be a external aluminum finned body with a cylinder liner.   The real issue is the fins ....and going aluminum is becoming probable.....   I did some research on carbide saws and I can run them at near 1000 rpm....as long as I have power....and I'm not sure I do.....at least not at 1000 rpm.....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on January 04, 2023, 12:16:34 AM
Sounds like the same kind of dithering I have been doing on how to make the Ohio parts. As you said to me, you'll figure it out!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 04, 2023, 01:00:41 AM
Sounds like the same kind of dithering I have been doing on how to make the Ohio parts. As you said to me, you'll figure it out!

YUP!     So here's the current design.    I'm going to back up and punt here.   I'm going to do this in the lathe

Rough turn the outside profile without the two flats  That will reduce the depth of the fins somewhat
The grooves are 1mm wide and 5mm deep.    I'll cut those with a "Thin Bit" grooving tool and the DRO.
Rough bore and finish profile. 
Part Off
Mill the flats in the fins and drill the holes for the cylinder head bolts


Thats a rough outline....I'll need to refine it.   

Then we'll see where I sit.    if that doesn't fly....I'll go to aluminum/2 piece construction.

Dave


Your turn Chris!    8) :stickpoke:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Mike R on January 04, 2023, 01:09:08 AM
For the fins, with the slitting saw you don't need to gang them up, you can run just one and cut each fin individually.  That's how I did the cylinders for my radial and they're fine little fins (0.5mm cutter, 0.5mm fin).  Done on the mill with the rotary table in its vertical axis and I spun the part, but I'm sure with a tighter mill than mine you could just interpolate around (my mill has too much backlash and eats small and delicate cutters on direction changes :( )


BTW - lathe was a no-go for fin cutting one at a time for me with 0.5mm fins (and initially 0.3mm until I made an executive design decision to increase their thickness).  Swarf would always invariably get caught between the cutter and bend over the fin. 
What's the fin thickness going to be?  If the groove is 1mm wide x 5mm deep, guessing the fin is similar in thickness to the width of the groove (i.e. 1mm), it may have enough strength for turning...
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 04, 2023, 01:13:53 AM
Mike   See my comment about my mill's HP at low speed range.   

Grooves and fins are 1mm    I think I can cut that with a quality grooving bit.   My lathe has the HP to make that...( at least 1 of my lathes)


Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on January 04, 2023, 02:42:53 AM
Sounds like the same kind of dithering I have been doing on how to make the Ohio parts. As you said to me, you'll figure it out!
...

Your turn Chris!    8) :stickpoke:
Um, err, I'm planning on doing something for the Ohio cylinders/frame, got some ideas, still perking away in the back of the brain. That should explain the funny noises leaking out my ears!   :Lol:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 04, 2023, 12:22:01 PM
 :lolb:...I hear ya bud.   Sometimes the best plan develops once you turn the lathe on....and not before.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 08, 2023, 01:08:49 PM
OK  so my division plates are "simmering" on the back burner while I wait for pleasurable material.  I'll be working from the crankshaft out.    I'll be working on gears, and then a respin of the oil pump....after that finish the upper and lower lay shafts, and then the block halves.

Gear blanks and gear cutting arbor tooling today pending support activities for my family....3C specific stuff.   I really want to be able to transfer between the lathe and the mill and minimize runout.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 08, 2023, 03:51:22 PM
OK 

2      32DP  56 T  x .085 thick   1.208 OD

2      48DP  32T  x .20   thick  0.708 OD

2      48DP  66T x .090  thick  1.416 OD

4      48DP  27T x .15 thick   0.604 OD

4      48DP  40T x .15 thick  0.875 OD

off to get the blanks set up
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on January 08, 2023, 04:00:27 PM
Wow, thats a lot of gears!    :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 08, 2023, 04:02:07 PM
Wow, thats a lot of gears!    :popcorn:

doesn't include oil pump gears.....that's just the timing gears....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on January 08, 2023, 04:05:56 PM
When done with this engine, you should build a clock styled on it!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Don1966 on January 08, 2023, 07:47:22 PM
Waiting on the gear making……..  :stickpoke:



 :popcornsmall:
Don
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 08, 2023, 08:51:26 PM
Waiting on the gear making……..  :stickpoke:



 :popcornsmall:
Don

Got a little tooling to make for this......and some blanks  ....making progress...
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 09, 2023, 02:11:45 AM
Some blanks and some arbors.   I'm made arbors for all the sizes that need it (.59375   0.5000  0.4375 and 0.375 diameter)   all with a 1/2  inch shank that fits a specific 1/2 in collet that ill share between the lathe and the mill.   As they get clocked the same each time, it keeps the runout down. 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on January 09, 2023, 02:17:56 PM
Looks a fun task  :ThumbsUp:  :ThumbsUp:  :wine1:

I will have to try gear cutting one day  :thinking:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 09, 2023, 06:27:38 PM
When done with this engine, you should build a clock styled on it!

I like that idea!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 23, 2023, 01:01:11 AM
I've had the firing order for the 917 for some time....but it occurred to me that I didn't know the cylinder ORDER.    :thinking:

That got sorted by Vixen directing me to this web site.     That nomenclature puts number 1 cylinder on the left side rear of the car....numbering going forward 1-6 while the right side goes from the rear forward  7-12

https://www.enginehistory.org/Piston/fo/FO.shtml

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on January 23, 2023, 12:32:26 PM
Quote
I've had the firing order for the 917 for some time....but it occurred to me that I didn't know the cylinder ORDER.    :thinking:

That is a significant detail and rather important for the Camshaft creation  ;D

I'm glad that Mike could help  :ThumbsUp: - interesting link.

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 23, 2023, 02:28:20 PM
Hello Dave and Per,

I had exactly the same problem with the W165; I knew the firing order but not how the cylinders were numbered. I had to work that out from first principles.  :killcomputer:

Knowing the cylinder numbering order is essential, when it comes to laying out the cams on the camshafts.

Good luck Dave when you get to do the 917's camshafts. It's an ideal occupation for these long, cold, winter's evenings.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 23, 2023, 02:42:44 PM
 :with the crank with the throws as is shown on the pictures of the engine   one could probably come up with several different firing orders and nomenclatures..as long as the cam is designed correctly   it'll work    but I do want that sound....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 23, 2023, 03:09:08 PM
There is only one 'right way' but several 'not so right' firing orders which would run, after a fashion.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on January 23, 2023, 03:19:47 PM
Quote
I had exactly the same problem with the W165; I knew the firing order but not how the cylinders were numbered. I had to work that out from first principles.
Is that method, and the principles involved, something that could be summarized in a post or short thread? Or could you suggest a source for reading up? I don't need to work out the proper cylinder numbering of an inline twin ( :headscratch:), but I am curious how it is arrived at for larger engines.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 23, 2023, 03:59:08 PM
Quote
I had exactly the same problem with the W165; I knew the firing order but not how the cylinders were numbered. I had to work that out from first principles.
Is that method, and the principles involved, something that could be summarized in a post or short thread? Or could you suggest a source for reading up? I don't need to work out the proper cylinder numbering of an inline twin ( :headscratch:), but I am curious how it is arrived at for larger engines.

Ron,
I don't want to hijack Steamers excellent Porsche 917 thread by answering you question here. I will start another thread.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: petertha on January 25, 2023, 06:45:22 AM
Mike, maybe you mentioned already but what will your cam timing be? (like intake/exhaust open/close relative to TDC/BDC etc.)
And will that be consistent to 'the big boy' or something specific to model running conditions?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 25, 2023, 11:07:11 AM
Dunno,  :hellno:     

 Ask Steamer, the 917 is his project

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 25, 2023, 11:16:22 AM
As I'm going to run this on methanol /oil mix   I'll be running timing along the lines.of Shillings engines.    I'd like to focus on easy starting not max power.....though I am hoping for a good "note" and some gear whine.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on January 25, 2023, 09:28:21 PM
Hope this is useful for you Dave
Top left spiral gear is the tacho drive on the inlet cam.
Notches at either end of the exhaust cam (lower) drive the scavenge pumps at front and rear.
Thrust bearing in the center (flanges), and drive gears attached via vernier plate integral to the shaft. Gear is located with standard bearing nut KM series.
Regards
John

EDIT - timing as per typ.906   Mezger details the lift and accelerations in the ASME paper
INLET   12.1   mm
EXHAUST   10.5   mm
Amax   0.0143   mm/°/°
Dmax   0.0056   mm/°/°

typ.906 cam timimg
INLET OPEN      104   °BTC   
INLET CLOSE      104   °ABC      
EXHAUST OPEN      100   °BDC   
EXHAUST CLOSE   80   °ATC   
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on January 25, 2023, 09:52:17 PM
Timing makes interesting reading in the context of petertha's excellent four stroke glow valve timing thread.
https://www.modelenginemaker.com/index.php/topic,10394.0.html (https://www.modelenginemaker.com/index.php/topic,10394.0.html)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 25, 2023, 11:06:13 PM
Thanks jcge!

I'm very interested in the ASME paper you reference.    Do you have a link?

Valve timing for model engines along with Compression ratio's vary significantly from full size practice.   Generally lower CR's and much less overlap on cams to make them much easier to start, tune and run.     As I understand it, a much milder cam timing is required to make a good running MODEL engine.    Valve timing and events such as those published by Westbury are generally to be preferred.

That said!

I want all the info on this engine!....... 8)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on January 25, 2023, 11:34:56 PM
Dave - I misspoke... its not ASME, it was the Proceedings of the Institute of Mechanical Engineers Vol 186 2/72 - "The development of the Porsche Type 917 car"
https://journals.sagepub.com/doi/pdf/10.1243/PIME_PROC_1972_186_005_02 (https://journals.sagepub.com/doi/pdf/10.1243/PIME_PROC_1972_186_005_02)
Regards
John

EDIT - trying to fix the URL link.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 26, 2023, 12:00:27 AM

Valve timing for model engines along with Compression ratio's vary significantly from full size practice.   Generally lower CR's and much less overlap on cams to make them much easier to start, tune and run.     As I understand it, a much milder cam timing is required to make a good running MODEL engine.    Valve timing and events such as those published by Westbury are generally to be preferred.


I totally agree with all of that. Mild valve timing will always make an easy starting, well mannered MODEL engine. And it also helps to fit a smaller carburetor than you thought necessary.

However, if you want POWER (to drive something other than the running stand); fit a wild cam with plenty of overlap, higher compression and a bigger carburetor; but it may be a pig to start and run.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 26, 2023, 12:01:58 AM
Dave - I misspoke... its not ASME, it was the Proceedings of the Institute of Mechanical Engineers Vol 186 2/72 - "The development of the Porsche Type 917 car"
https://journals.sagepub.com/doi/pdf/10.1243/PIME_PROC_1972_186_005_02 (https://journals.sagepub.com/doi/pdf/10.1243/PIME_PROC_1972_186_005_02)
Regards
John

EDIT - trying to fix the URL link.

Thanks John!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on January 26, 2023, 12:02:51 AM
also buried in this doc...
https://porschecarshistory.com/wp-content/old/biblio/17/Porsche-917.PDF (https://porschecarshistory.com/wp-content/old/biblio/17/Porsche-917.PDF)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 26, 2023, 12:09:56 AM
also buried in this doc...
https://porschecarshistory.com/wp-content/old/biblio/17/Porsche-917.PDF (https://porschecarshistory.com/wp-content/old/biblio/17/Porsche-917.PDF)

Thanks John!   Reading up!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on January 26, 2023, 12:34:33 AM
There's a ton of good stuff in that PDF. Thanks for posting it!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: petertha on January 26, 2023, 04:46:06 AM
Dunno,  :hellno:     

 Ask Steamer, the 917 is his project

Mike

Sorry about that Mike, I actually knew that LOL. Late night typing & getting my exotic engines crossed. Anyways I continue to tinker with my cam spreadsheet tools & its been somewhat revealing (to me). I've also been working on a kind of cookbook cam phasing/orientation procedure... well lets just call them personal scribbles & kind of a symbol matrix for now. This came about because I as suspicions of a certain cam & getting it wrong in real life seemed like a lot of work to be avoided. There are quite a few variables that enter the picture. Anyways, it was good to work through the problem on my own. So I look forward to whenever the topic comes up in discussion.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 26, 2023, 10:50:51 AM
Dunno,  :hellno:     

 Ask Steamer, the 917 is his project

Mike

Sorry about that Mike, I actually knew that LOL. Late night typing & getting my exotic engines crossed. Anyways I continue to tinker with my cam spreadsheet tools & its been somewhat revealing (to me). I've also been working on a kind of cookbook cam phasing/orientation procedure... well lets just call them personal scribbles & kind of a symbol matrix for now. This came about because I as suspicions of a certain cam & getting it wrong in real life seemed like a lot of work to be avoided. There are quite a few variables that enter the picture. Anyways, it was good to work through the problem on my own. So I look forward to whenever the topic comes up in discussion.

Hi Peter,
I enjoy your ruminations on timing as I too would like to internalize the nuances of engine parameters with model engines.   Feel free to post what you think appropriate.   If this was a Compound steam engine, I'd know EXACTLY what was needed....been there done that.     This is all still new to me, but I'm learning as I go.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 26, 2023, 10:56:02 AM
Been giving the cylinders a lot of thought as of late.     I think trying to drive a slitting saw through 12 of them ( minimum) is asking for drive problems.....and I don't need drive problems.

That said, I'll be going at this a little differently.    I'll take a page out of the Edwards 5 radial design, and  I'll make a aluminum cylinders with cast iron liners.   This is a lot more work, but I think the risk reduction is worth it.    Making fins in the lathe will be easy in comparison with aluminum.     The cylinder heads will still need to be milled, but with aluminum, it should be far less of a drama as compared to 1144SP steel.

Best way to keep going on a project,  make a decision and then execute.....onward!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: ozzie46 on January 26, 2023, 10:39:58 PM
Hello Dave,

You seem to want/need to avoid the use of 1144SP steel for the cylinders because of potential fin cutting issues. Instead you are considering aluminum finned cylinders with cast iron liners. What is the objection to making the whole finned cylinder from cast iron? I am sure that's what Craig did on his big 'Le Craig' rotary engine.

Just thinking




Mike


Or use 12L14 leaded steel. I cut fins in the cyls for a nine cyl radial that were .031 grooves in the stuff, no issues . Ground up 2  HSS cutting bits
 to .031. Broke 1 ,my fault , lost concentration.

12L14 is a pleasure to machine.

Ron
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 28, 2023, 11:01:45 PM
Thanks Mike and Ron for your responses.

Looking at the machinability of the materials, it's attractive to go with Aluminum with an iron liner, like the Edwards and the Ohrndorf.    Running on methanol, there is concern about corrosion.  I have seen engines built with both 1144SP and Iron.   Petertha was concerned about corrosion with methanol on the steel parts, and decided to go with cast iron liners as they have a good reputation with iron rings.      I too will have these problems with a multicylinder that I know I wont get EVERY last drop of methanol out of after a run.   After run oils are out there, but I'm not convinced that I'll get it all.  Petertha also had issues with the liners shrinking and going out of round on the Ohrndorf after pressing them into the sleeves.

Machineability of 1112 Carbon steel being 100%   1144SP is 83%, 12L14 is 170%,  while Gray Iron is about 48%.    Aluminum alloys of the wrought material variety are at about 360%.

The above facts would point to a two piece solution.....Armed with that and a closer look at the design,   the manifest problem and there is a problem became obvious.....

1.   The sections of the cylinder are thin....real thin.    Making this cylinder in two pieces would be a challenge and keeping the parts together ....I'm not sure I'm going to
2.   Mixing Steel with Aluminum and then soaked with a substance that corrodes metals sounds like galvanic action taking over quickly.......hmmmm.  Getting the heads off this engine is going to be a right royal PITA!.....the cam boxes have to come off.   Like it might be easier to split the case! :hellno:
........ :zap: :headscratch:

So   hard to starboard and come about!    back to 1144SP.     And in one piece.
1.  One material....less chance of corrosion.
2.  Better machinability than Iron, and Im not burying my lathe in iron chips.....
3.  If I'm thoughtful enough, and do all the fin making in the right order, I can cut all 8 x 12 plus extra's    lets call it 120 grooves   1mm wide x 5mm deep fins on the lathe.....time to buy some more thin bit!

Nicole thin bits      .043 wide by .236 depth of cut.   Best price so far is $21 EACH.      ( I have a holder for them.)   I'll keep looking, but Bubba! (Steve Huck )   if you know a cheaper place to buy...let me know.

4.   I won't need to worry about the liner closing down and going out of round after final machining and lapping....
5.  One less turning fixture to make....

It's also clear to me that I will need a good after run procedure that flushes the cylinders and the block with after run oil.   




   

 



Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 28, 2023, 11:58:40 PM
Model Cam timing

Thanks to Petertha for his great work! 

Im liking the OS FS26.....its very similar to the bore stroke and compression ratio that I'm going with, and is described as a beautiful engine that is very easy to start on methanol and 10% nitro with synthetic oil.

Something to shoot for

Dave

http://sceptreflight.com/Model%20Engine%20Tests/OS%20FS-26%20Surpass.html
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: petertha on January 29, 2023, 07:37:55 AM
I think you might be referring to this post. Sheesh, has it really been that long? I really must get on with my documentation. I promise!

https://www.modelenginemaker.com/index.php/topic,10155.120.html

Anyways, maybe some commentary. The way I initially went about my liners & cylinders was not efficient or correct. I was initially after a very mild interference fit between CI liner aluminum cylinder mostly because that was my RC experience. Just a little bit of soak time in a 350-400F toaster oven & the liner could be removed & replaced. But those engine bodies are almost always die cast & under close examination the cylinder bores are very well finished, maybe  honed or lapped. The liner OD's are extremely well finished. I lapped my liner OD's but I now believe my cylinders were a little more 'lively'. The shape is not symmetrical, for sure more mass near the top & rectangular base; possibly conditions for post machining stress relief. I also depended on a reamer for the cylinder bore which I thought was pretty good, but lapping exposed it wasn't quite perfect either. So a 1/10" here, 2/10" there..my fit was OK but not perfect.

Then I read the fine print of another builder (Jung) & his interference recommendation amount was more than a slip fit & he wrote necessary for dissipating heat. So when I went down this path, I still used heat to assemble liner & cylinder, no pressing or adhesive. But aluminum can expand a lot & if you don't get the diameters right it is possible/likely for the liners to get squeezed especially if they are thin wall. But all I was really trying to say in this episode was don't waste effort lapping the bores unless you are going for that magic light slip fit. Next engine I would simply leave enough material in the liner ID for lapping & save that operation for very last. Ie. assemble cylinder & liner the same way (thermally), let them stabilize over some reasonable period & let them do what they may. Then do the final liner lap. I had my finished assemblies sitting in a box for quite a few months while building other components & I could no detect any bore deviation from last lapping dimension. Hope they stay that way.

In terms of materials, I also oscillated between alloys mentioned. I opted for CI because of its stated good wear properties with a CI ring. I am very happy with the finish & stability. It was a bit messy but fun to machine & you can achieve a mirror finish if desired. Apparently CI was used in glow engines before chrome/hard coating came into the picture (castor oil days). 12L14 machines like a dream but my only concern was possibility of 'a bit more' corrosion rate. Purely based on unscientific data: machined 12L14 stock in my scrap box shows some discoloration over time & I live in very dry air environment. But I have also seen 12L14 used in many built engines, but predominantly gasoline which I think are not as aggressive corrosion wise as methanol? I considered 1144SP as well, my crankshaft is made from it. It finishes very well too but it was my impression it was tough stuff. I did lapping on OD surfaces & it just seemed to take forever. Diamond helped. But this might just be my imagination, a lot of time expired between crankshaft & liners. Lapping is mind numbingly slow, I dream about access to a Sunnen hone. But I'd say have a fun R&D day & try a liners of each material on your top list, see what you think. You have so many more to make on the V12 than I did.

Anyways, I will continue to be quite religious about interim engine storage liberally soaked with oil & stored in Ziplock bags, even if it means partial disassembly to ensure everything is coated. Come running season, drain & wipe. I've done this for years on expensive RC engines back in the day. Aside from running wear they look spotless. Whether its pneumatic tool oil, or (non additive) hydraulic oil, or Klotz.. doesn't seem to matter as long as its coating everything & doesn't react to other alloys used in the engine. Hopes this helps!

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 29, 2023, 10:41:44 AM
Hey Peter,
We violently agree!
I am fond of CI as it does finish nicely but I do want/need1 piece cylinders and I want them to last a bit....this engine is a real "Stack of parts" and identical bore and length are critical....yes 1144sp isn't as friendly as 12L14 but it will lap up nicely in my experience.  Again   some tooling will be required lol.  I think 2 piece construction is out if I want to stay at least NEAR prototypical.  For after run I plan on flooding the engine internally with oil and draining it. Cylinder bores as well through the glow plug ports.   Thanks for looking In! :praise2:
Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2023, 01:50:09 AM
Hope this is useful for you Dave
Top left spiral gear is the tacho drive on the inlet cam.
Notches at either end of the exhaust cam (lower) drive the scavenge pumps at front and rear.
Thrust bearing in the center (flanges), and drive gears attached via vernier plate integral to the shaft. Gear is located with standard bearing nut KM series.
Regards
John

EDIT - timing as per typ.906   Mezger details the lift and accelerations in the ASME paper
INLET   12.1   mm
EXHAUST   10.5   mm
Amax   0.0143   mm/°/°
Dmax   0.0056   mm/°/°

typ.906 cam timimg
INLET OPEN      104   °BTC   
INLET CLOSE      104   °ABC      
EXHAUST OPEN      100   °BDC   
EXHAUST CLOSE   80   °ATC

A friend of mine pointed out that cam receipt makes for 388 degrees of duration and 185 degrees of overlap......his comment was....."holy mother or god"   LMAO!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jasonb on February 04, 2023, 07:15:46 AM

 lets call it 120 grooves   1mm wide x 5mm deep

Nicole thin bits      .043 wide by .236 depth of cut.   Best price so far is $21 EACH.      ( I have a holder for them.)   I'll keep looking, but Bubba! (Steve Huck )   if you know a cheaper place to buy...let me know.
 

If you go with their Grooving & Cutoff inserts (neutral) rather than standard grooving you will get closer to your 1mm with their 0.039" width and an extra mm of depth capability. These are what I use most of the time in my holder for parting small parts and grooving, even parted some 200mm dia streel tube the other day with them. Never found them cheap but they are good.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2023, 10:22:35 AM

 lets call it 120 grooves   1mm wide x 5mm deep

Nicole thin bits      .043 wide by .236 depth of cut.   Best price so far is $21 EACH.      ( I have a holder for them.)   I'll keep looking, but Bubba! (Steve Huck )   if you know a cheaper place to buy...let me know.
 

If you go with their Grooving & Cutoff inserts (neutral) rather than standard grooving you will get closer to your 1mm with their 0.039" width and an extra mm of depth capability. These are what I use most of the time in my holder for parting small parts and grooving, even parted some 200mm dia streel tube the other day with them. Never found them cheap but they are good.
Thank you Jason

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: petertha on February 04, 2023, 06:43:35 PM
I'd have to go back to my notes but just a potential heads up. When I did my radial cylinders I confirmed the DOC was just under the referenced value given by Nikcole. What I failed to take into consideration was the taper profile of the cylinder itself. You might run into similar situation I encountered where a portion of tool holder starts to make contact with the larger stock diameter in adjacent proximity, which therefore limits DOC. If the part diameter does not vary, or vary much, no worries.

Nikcole tools are spendy but I really like how they cut. I've has some success with homebrew HSS but less so on narrow + deep kerf combinations
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2023, 06:50:37 PM
Thanks Peter!!!

I'm going to see what other options are available.   I have a rear mounted tool post as well, so I may just try a 1mm parting tool choked up as well and see.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jasonb on February 04, 2023, 06:52:27 PM
You can get over that with a left hand holder of if you have enough crossslide movement run in reverse and come at it from behind.

Actually could possibly hold R/H tool upside down and still running in reverse come at it from the front.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2023, 09:40:39 PM
You can get over that with a left hand holder of if you have enough crossslide movement run in reverse and come at it from behind.

Actually could possibly hold R/H tool upside down and still running in reverse come at it from the front.

I have several part off tools for the front and rear tool post.....1 will work  ( my rear holder cuts upside down)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 05, 2023, 01:52:35 AM
Gears, Gears and more gears!     tonights installment in the box....(2) 66 tooth 48 dp cam timing gears....they need the lightening holes put in.     but after all the other gears are cut....the dividing head is set up.     It mounts in the 4" vise and works really well!    I'm glad to took little detour to get that dividing head tooled and going.    I have made some arbors for it, and it's pretty accurate all in all 

on to more gears!  I have about 20 to make...

Dave 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on February 05, 2023, 02:09:49 AM
Quote
on to more gears!  I have about 20 to make...
You'll have 'em done in no time...     :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 05, 2023, 02:18:18 AM
Thats a lotta gears!   :popcorn: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 05, 2023, 02:49:22 AM
One of the cam gear towers.....Additionally, there are (2) 40 tooth cam gears with vernier holes....

There are 4 oil pump gears

And there are the distibutor gears  ( cross helical )

So ......cutting gears for a while!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on February 05, 2023, 04:57:52 AM
That's a great gear cutting seetup, Dave!  Nice dividing head!  And some great looking gears coming off the line  :ThumbsUp: :popcorn:

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on February 05, 2023, 09:50:02 AM
Looks like the teeth are perfect on the first two Gears  :praise2: - that bodes well for the setup and the rest of them  :cheers:

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 05, 2023, 12:52:54 PM
Looking good Dave,   :cheers:

Don't you just love it when the last tooth turns out to be the same width as the first. :ROFL:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 05, 2023, 12:57:31 PM
Looking good Dave,   :cheers:

Don't you just love it when the last tooth turns out to be the same width as the first. :ROFL:

Mike
And you know it has to be the last one when the pin goes into the hole you started.....then you can watch the last cut!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 05, 2023, 01:20:32 PM
Vernier holes? How does that work?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 05, 2023, 02:04:58 PM
Vernier holes? How does that work?

Index plate holes      In this case I had to cut a 66 tooth gear.    The gear ratio of the dividing head is 40/1....so  I need to rotate the index crank 40 times to get 1 revolution of the work piece.

That works out to  40/66 or each tooth index requires 0.606 of a turn of the index crank.   How is that accomplished?

Well    A dividing head comes with "index plates" made up with different count hole circles....with a Browne & Sharp style head they are the following
Plate 1     15  16   17  18  19  20

Plate 2     21  23  27  29   31  33

Plate 3     37  39  41   43   47  49

Not the only ones mind you, but certainly the most common .

It can be seen that 40/66 reduces to 20/33....   Well   plate 2 has a 33 count hole cirdce

So if we index 20 holes in a 33 hole index, we get our 0.606 of a turn..   

Now it can be pretty tedious to count this every time, so most dividing heads have "sector arms" which you can set to that hole count spacing and then only have to count the 20 holes once.

So you make your first cut,   index 20 holes, move your sector arm pair up to the new position, and lock the spindle.   Then take the next cut

I always start with the index pin at the 12 oclock position which on my dividing head plates, has the hole counts engraved on them  ( see the picture below)

 In the situation here, the last cut tooth puts the sector arms, which are analogous to a page holder in a book, in the same position as the first tooth and the 33rd tooth.  so when you see that you  know where you are.....
Here I have a picture of my recently acquired dividing head, which came with only 1 plate from another dividing head.   So I made up some new index plates and did some repairs and made up some everyday tooling like arbors and such.   This particular one is attractive because It takes 3C collets and I can share that tooling with my Southbend..     It is really attractive because it is small enough to sit in my 4" vise.    It was originally made I believe by Hardinge back in the 1930's for their TUB line of mills.   Not having to take the vise off to cut a gear is really nice..    I have a BS-0 head, but its so big, it fills the table and limits my range. 

Making one of the plates.
 
https://www.youtube.com/shorts/ol0Q6PWTUmg


Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 05, 2023, 02:39:25 PM
Oh, the way you mentioned it in the earlier post,  "40 tooth cam gears with vernier holes", I thought there was something special on the gears themselves.
 :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 05, 2023, 03:12:27 PM
One of the cam gear towers.....Additionally, there are (2) 40 tooth cam gears with vernier holes....

There are 4 oil pump gears

And there are the distibutor gears  ( cross helical )

So ......cutting gears for a while!

Dave

When you said  "40 tooth cam gears with vernier holes" I thought you were referring to the ring of 17 bolt holes that you can see on the end of each camshaft on the 917 cross section shown below. These holes allow for the vernier adjustment of each Camshaft with respect to the Crankshaft. When you build up the whole camshaft gear train you will probably find the camshaft position may be out by part of a tooth width (that could be as much as 9 degrees). The vernier holes allow you to rotate the gear on the camshaft in 1/17 of a tooth increments until the timing is spot on, to within 0.5 degree. It's quite normal to only fit only five or six bolts into the available vernier holes.

(https://listerengine.com/coppermine/albums/userpics/10013/Porsche917Motor11109163853.jpg)

There is a similar vernier adjustment on the Mercedes Benz W165 camshaft gears. You can see the uneven bolt spacing.

(https://listerengine.com/coppermine/albums/userpics/10013/IMG_0593smal.JPG)

Mike



Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 05, 2023, 04:56:04 PM
One of the cam gear towers.....Additionally, there are (2) 40 tooth cam gears with vernier holes....

There are 4 oil pump gears

And there are the distibutor gears  ( cross helical )

So ......cutting gears for a while!

Dave

When you said  "40 tooth cam gears with vernier holes" I thought you were referring to the ring of 17 bolt holes that you can see on the end of each camshaft on the 917 cross section shown below. These holes allow for the vernier adjustment of each Camshaft with respect to the Crankshaft. When you build up the whole camshaft gear train you will probably find the camshaft position may be out by part of a tooth width (that could be as much as 9 degrees). The vernier holes allow you to rotate the gear on the camshaft in 1/17 of a tooth increments until the timing is spot on, to within 0.5 degree. It's quite normal to only fit only five or six bolts into the available vernier holes.

(https://listerengine.com/coppermine/albums/userpics/10013/Porsche917Motor11109163853.jpg)

There is a similar vernier adjustment on the Mercedes Benz W165 camshaft gears. You can see the uneven bolt spacing.

(https://listerengine.com/coppermine/albums/userpics/10013/IMG_0593smal.JPG)

Mike

Yes we are talking about the same thing

Sorry Chris missed that point......Ive got the vernier on the VDH on the mind.....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 05, 2023, 05:19:21 PM
Ah - now I understand!  Thanks Vixen/Dave!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 06, 2023, 12:42:14 AM
And two more
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 06, 2023, 11:21:02 AM
"That's another fine mesh you've got us into, Stanley"   :ROFL:

Yesterday you gave a master class explanation of the intricacies of using a dividing head and index plates to set the number of teeth on the gear wheel.

Today's question is. How do you decide the depth of cut to form the gear teeth?    Do you
A.     Use some a formula from a text book (such as Ivan Law's 'Gears and Gear Cutting')
B.     Do use use a look-up table
C.     Use then D+ value etched on the side of the involute cutter
D.     Another way

I tend to use option C above and it seems to give good results in my gear trains.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 06, 2023, 01:26:17 PM
I usually use the hand calculation as there are a lot of points of error not the least of which is gear run out and cutter runout , to say nothing of getting the cutteron center.    All of my 48 dp cutters are different widths by up to 1  mm...and  .005" run out..so worrying about tenths seems silly..   at least with Chinese cutters and shop made arbors.  I usually wait on fitting the gears till I can set them on tool makers bushings and confirm a good mesh.      We can start a thread if we want to get into it.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jasonb on February 07, 2023, 07:10:45 AM
That's what I tend to do to just depth the gears and set the backlash and fit at what that PCD ends up being. Initial cut is to formula for me.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: john mills on February 07, 2023, 10:38:15 AM
i have cut gears usually turning the blank to the calculated od  often on the drawing then i cut to the depth which is on the cutter
mostly my gear cutting was on hobbing or a shaping machine a fallows type.but the only way is to cut the first ones and check
if the gears are heat treated try one first and check how it comes out after it has been heat treated .i only had limited
information  about these processes but the ones i did work .miner adjustment can be made to improve the fit .referd to machinery's hand book  old ones.
john
 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 07, 2023, 12:30:43 PM
I made dedicated arbors with 1/2" shank to fit a specific 3C collet that I save for gear cutting.  These arbors are clocked to the "G" in Hardinge on the face of the collet and final turning was done then.   When they are used, I always clock them to that spot with some emphasis on rotating the arbor in the collet as I close it.  I typically get less than 0.0005" runout of the arbor in both the lathe and the dividing head..      The gear blanks are mounted on the arbor and final OD is done just prior to cutting the teeth and without dismounting them from the arbor.   I consider these arbors expendable, as they can sometimes get cut when cutting the gears, and as they get more or less worn, I make new ones.   I also make brass arbor bushings that I also consider expendable.   Currently I have arbors for  3/8,  7/16, 1/2 and 19/32.  all with 10-32 threaded holes for a clamp screw.    They are pretty trivial to make, and I can make them as long or as short as is needed.      This constitutes my "system" for cutting gears.

If we would like to continue this discussion, please start a new thread so I can keep this for the 917 project.     Thank you.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 12, 2023, 03:40:18 AM
"That's another fine mesh you've got us into, Stanley"   :ROFL:

Yesterday you gave a master class explanation of the intricacies of using a dividing head and index plates to set the number of teeth on the gear wheel.

Today's question is. How do you decide the depth of cut to form the gear teeth?    Do you
A.     Use some a formula from a text book (such as Ivan Law's 'Gears and Gear Cutting')
B.     Do use use a look-up table
C.     Use then D+ value etched on the side of the involute cutter
D.     Another way

I tend to use option C above and it seems to give good results in my gear trains.

Mike

Your way is the best Mike.   I've dug into this a bit and it is truly the best way to determine cut depth...as it includes the Pressure angle, the DP and any small error in the gear cutter....what remains is the amount of clearance you desire.  So this cut is called the minimum depth.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 12, 2023, 03:44:35 AM
Progress today!   One more gear and the cam drive line gear cutting will be done!
I have a bunch of holes to put in....but I'm gaining on it    family portrait  but you can see the gear train layout...all of this is driven from the gear at the center of the crankshaft.   The two last gear blanks straddle the crank.    After this I'll be cutting the pump gears and the pump drive gears.  After that distributor cross helix gears...but those can wait...

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on February 12, 2023, 05:28:41 AM
Them's a LOT'o gears, Dave!  A lot of meticulous work represented in that last shot!  :popcorn: :popcorn:

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 12, 2023, 10:42:05 AM
Nice work. You are making good progress  :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on February 12, 2023, 03:00:31 PM
Excellent! :ThumbsUp:  :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 12, 2023, 03:08:26 PM
More impressive work!   :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on February 12, 2023, 03:58:49 PM
Splendid  :praise2:  :praise2:  :wine1:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on February 12, 2023, 05:37:15 PM
Great to see more parts in the family shot - certainly one of the really interesting builds for a Petrolhead like me  ;D

Per        :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 13, 2023, 12:54:25 AM
OK!   Good weekend!    All the cam drive gears have had their teeth cut.   There are some second ops needed but the gears teeth are done.   Below you can see the layout.   The crankshaft would be directly in the middle of this layout....like I said...Porsche loved their gears!
the 4 outmost gears are the camshaft drive points.   The one in the top center drives the iconic cooling fan via bevel gears, and the distributors, while the bottom most one is the output to the flywheel/clutch.  Porsche did this to take power from the center of the crank and not the end, resulting in less stress on the crankshaft....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on February 13, 2023, 01:04:08 AM
Nicely done Dave - it's really taking shape now.
Did you use constant tooth depth for the bevel gears or some other arrangement?
John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 13, 2023, 01:20:25 AM
I built a pendulum weight driven clock that strikes the hours and half hour that has fewer gears.  Wow.


 :praise2:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 13, 2023, 01:28:05 AM
Nicely done Dave - it's really taking shape now.
Did you use constant tooth depth for the bevel gears or some other arrangement?
John

The bevel gears are the only gears I purchased.    all the rest were cut by me.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 13, 2023, 01:30:00 AM
I built a pendulum weight driven clock that strikes the hours and half hour that has fewer gears.  Wow.


 :praise2:

Next is the oil pumps....starting with....you guessed it.....cutting gears    12 tooth and 24 tooth 48 DP.....6 more gears to cut!!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 13, 2023, 01:36:50 AM
Holey shop elf.  How many gears total in the entire engine??
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 13, 2023, 01:47:52 AM
Holey shop elf.  How many gears total in the entire engine??

I think I count 29...
In the actual engine, there were 4 scavenge pumps at the bottom of the cam boxes, so 37.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 13, 2023, 01:53:38 AM
The key reason for getting these gears done now, is to set the mesh to minimize lash.   I'll support all of these gears on toolmakers buttons and nail down the exact locations.    This will minimize the lash, so I've got a hope of timing the cams accurately.   Doing this now will drive the final dimensions of the block.     

To do this, I'll lay out the gears on a flat plate....and note the best dimensions....and go from there.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 13, 2023, 03:37:13 PM
It appearsI locked this thread in error....my bad

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on February 13, 2023, 07:44:22 PM
It's open now  :) What a lot of gears but fun to follow along  :ThumbsUp:  :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 20, 2023, 01:48:10 AM
OK    all the gears are cut.   I have a few keyways to cut,  some lightening holes, and I need to finalize a bore or two, but all the teeth are cut.     Next will be the pump body as well as the upper and lower way shafts.....

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Mike R on February 20, 2023, 02:17:02 AM
looking good, I like the storage bin organizer to keep the "exploded view" of the engine in!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: vtsteam on February 20, 2023, 02:42:27 AM
Yes, Steamer, that's pretty cool that you can fit a whole crankshaft assembly in one compartment, and all those gears, etc in the others! Beautiful work!  :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on February 20, 2023, 05:48:34 AM
Very nice looking set of gears, Dave!

So, are those lightening holes going to be followed a few seconds later by thundering holes?   :lolb:

Kim

(I just crack myself up sometimes!  :ROFL:)

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 20, 2023, 12:29:18 PM
Thunder and frightening  :help:

Are the 12 tooth gears for the pressure and scavenger pumps? What size cutter are you using?

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 20, 2023, 01:06:27 PM
Thunder and frightening  :help:

Are the 12 tooth gears for the pressure and scavenger pumps? What size cutter are you using?

Mike

48 DP   number 8 cutter   pump runs at half engine speed
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 20, 2023, 04:39:47 PM
Thunder and frightening  :help:

Are the 12 tooth gears for the pressure and scavenger pumps? What size cutter are you using?

Mike

48 DP   number 8 cutter   pump runs at half engine speed

The driven gear is a 24 tooth gear cut with a #5 cutter.....FYI.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jan D on February 20, 2023, 09:56:07 PM
Nice thread! Seems that I am a bit late to the party, but if there are still any questions regarding the original engine... We happen to have some in our shop.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 20, 2023, 10:13:45 PM
Nice thread! Seems that I am a bit late to the party, but if there are still any questions regarding the original engine... We happen to have some in our shop.

Hello Jan,

Welcome to the MEM forum. There is a special section where you can introduce yourself and tell us more about whats in you shop.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 21, 2023, 01:45:05 AM
Beginning to look more the part!
Assembled and some prototypical speed holes.


Hello Jan!   I am very interested in getting some photo's of various parts.

That said,   Vixen is correct.   When you get a moment, post a note in the introduction section and tell us about yourself! 

Welcome!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 21, 2023, 03:29:56 AM
Terrific!  How are the smaller gears attached to the larger ones? Or will they both be keyed to the shaft separately?


 :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 21, 2023, 04:27:00 AM
Terrific!  How are the smaller gears attached to the larger ones? Or will they both be keyed to the shaft separately?


 :popcorn:

.002" press fit on a .562 diameter.   I will be putting two #2 set screw "dutchmen"  at 180 degrees  to make sure.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on February 22, 2023, 12:17:39 AM
Terrific!  How are the smaller gears attached to the larger ones? Or will they both be keyed to the shaft separately?


 :popcorn:

.002" press fit on a .562 diameter.   I will be putting two #2 set screw "dutchmen"  at 180 degrees  to make sure.

Dave


Shouldn't 2 set screws be 90 degrees apart?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 22, 2023, 12:27:22 AM
Terrific!  How are the smaller gears attached to the larger ones? Or will they both be keyed to the shaft separately?


 :popcorn:

.002" press fit on a .562 diameter.   I will be putting two #2 set screw "dutchmen"  at 180 degrees  to make sure.

Dave


Shouldn't 2 set screws be 90 degrees apart?

2 screws put in parallel to the shaft at the press fit joint.  Half in each side of the joint.       Not radially like normal set screws.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 22, 2023, 12:38:36 AM
Central pivot does not transmit torque.  Only this press fit joint, and I dont want it to spin or move axially, so keying it in with two short screws fixed with high temperature retaining compound will make sure it stays put.    I suspect it will be strong enoug to rip all the teeth off....which is preferable.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jan D on February 22, 2023, 12:48:12 AM
Nice thread! Seems that I am a bit late to the party, but if there are still any questions regarding the original engine... We happen to have some in our shop.

Hello Jan,

Welcome to the MEM forum. There is a special section where you can introduce yourself and tell us more about whats in you shop.

Mike

Just done that, thanks!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 24, 2023, 03:28:19 PM
Speed holes In!
On to the pumps!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 24, 2023, 03:57:27 PM
Awesome - artwork!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: vtsteam on February 24, 2023, 04:05:23 PM
Aaaah, more gooder!  :ThumbsUp: :ThumbsUp: :popcorn: :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on February 24, 2023, 05:51:08 PM
Beautiful gear train, Dave!  :popcorn:
Must feel good to have all those complete :)
Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 24, 2023, 06:47:17 PM
Beautiful gear train, Dave!  :popcorn:
Must feel good to have all those complete :)
Kim
Yeah it was getting  time to make.somerhing other than another gear   My new Dividing  Head worked awesome though
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on February 24, 2023, 06:52:27 PM
Splendid  :praise2:  :praise2:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on February 24, 2023, 08:36:39 PM
Great family shot of all the gears in the Train, Dave  :praise2:

Looking forward to see the Oil-Pumps emerge from the Bar  :D

Per       :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on February 24, 2023, 09:45:57 PM
That's just a lovely set of gears, Dave! :ThumbsUp: :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 26, 2023, 01:48:19 AM
Third pass at the oil pump housing....and I got a little greedy....and set it up for the second op in the vise.....that was a mistake.....I deformed it a thou or so.....and I lost the mesh.....oh well do it again!

 :toilet_claw:

OK  so make a new one....and a fixture to hold it for the second op.......sigh
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 26, 2023, 01:55:00 AM
Teeny pump!  So, the oil gets trapped in the triangular spaces between the teeth and the walls, carried around the perimeter, and out the other hole? That sort of pump could pump either direction by changing the rotation, right?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 26, 2023, 02:10:06 AM
Teeny pump!  So, the oil gets trapped in the triangular spaces between the teeth and the walls, carried around the perimeter, and out the other hole? That sort of pump could pump either direction by changing the rotation, right?
Correct.    Radial clearance needs to be close...but axial clearance needs to be closer!!!   It's a small pump but at 4000 rpm.....it'll move some oil for sure!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 26, 2023, 02:20:09 AM
Teeny pump!  So, the oil gets trapped in the triangular spaces between the teeth and the walls, carried around the perimeter, and out the other hole? That sort of pump could pump either direction by changing the rotation, right?

Ron Collonna's Offy has the same pump running 50% slower than this .....this will be more than enough....


Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: vtsteam on February 26, 2023, 02:43:00 AM
Positive displacement pump -- the roots blower is similar, and can be used for either pressure or vacuum. That IS a tiny gear pump. Very nice!  :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Art K on February 26, 2023, 03:43:08 AM
Dave,
That oil pump looks good! Still following along though I may not say anything.
Art
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on February 26, 2023, 05:02:41 AM
Cute little oil pump, Dave!  Too bad about the re-do :(

But the second one goes faster? (He says, with a sheepish grin   :embarassed:)

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 26, 2023, 09:38:31 AM
Hello Dave,

That pump looks great  :ThumbsUp: :ThumbsUp: but much smaller than I imagined.
Is it one of the scavenger pumps for the cam boxes or part the main pressure/ scavenger pump?

Whats next?

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 26, 2023, 12:31:16 PM
Hello Dave,

That pump looks great  :ThumbsUp: :ThumbsUp: but much smaller than I imagined.
Is it one of the scavenger pumps for the cam boxes or part the main pressure/ scavenger pump?

Whats next?

Mike

That's the oil pump    The scavenge pump has gears about twice as long.    12 T   48 DP.   OD is .291"
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 26, 2023, 12:35:49 PM
Hello Dave,

That pump looks great  :ThumbsUp: :ThumbsUp: but much smaller than I imagined.
Is it one of the scavenger pumps for the cam boxes or part the main pressure/ scavenger pump?

Whats next?

Mike






Well,   Make a new housing, and then make the scavenge pump housing and the other two plates.   The two pumps are situated as 1 assembly, much like yours Mike.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 26, 2023, 12:50:28 PM

Ron Collonna's Offy has the same pump running 50% slower than this .....this will be more than enough....

Dave

So, are your pressure and scavenger pumps running at engine speed or at half engine speed like Ron's Offy engine?

They normally design the pumps to run as slowly as possible to prevent cavitation. You may need to run a test on your pumps to check for any speed limitations  :thinking: :thinking:

Cheers   :cheers:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 26, 2023, 01:01:06 PM

Ron Collonna's Offy has the same pump running 50% slower than this .....this will be more than enough....

Dave

So, are your pressure and scavenger pumps running at engine speed or at half engine speed like Ron's Offy engine?

They normally design the pumps to run as slowly as possible to prevent cavitation. You may need to run a test on your pumps to check for any speed limitations  :thinking: :thinking:

Cheers   :cheers:

Mike

Ron's runs at 1/3   I'm running 1/2.    and yes   we will need to test,  which I'll need to do as part of the development process anyway, but if anything I have more flow than Ron's Offy...at least on paper.....   If it ends up being too much, I can thin the gears,     Too fast?   I can change the drive gear.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 26, 2023, 01:09:27 PM

Ron's runs at 1/3   I'm running 1/2.    and yes   we will need to test,  which I'll need to do as part of the development process anyway, but if anything I have more flow than Ron's Offy...at least on paper.....   If it ends up being too much, I can thin the gears,     Too fast?   I can change the drive gear.

That sounds good. You could do a test next week, driving the pumps from the lathe spindle at different speeds and an old ice cream tub to catch the oil.

Cheers   :cheers:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 26, 2023, 01:13:22 PM
That's the plan!     I don't know if it's going to be next week though   :lolb:

The honey do list is strong...or as Mr  Marley stated......."It's a ponderous chain!"


I'll need something other than my SB to spin it at 4000 rpm  ( half engine max speed of 8K)  .....maybe the mill
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 26, 2023, 01:35:09 PM
Also keep in mind that the 917 engine pump, is a pressure pump and 2 scavenge pumps.   The model I'm building is 1 pump and 1 scavenge pump but combined in one unit like the original

fussy little assembly!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 26, 2023, 01:38:17 PM
The reality is, as long as it doesn't cavitate, I can bleed off what I don't need and run it back to tank along with the scavenge return.   As the model is set up with 7 spray nozzles, I can throttle delivery with a regulator dumping back to tank
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 26, 2023, 01:44:40 PM
The reality is, as long as it doesn't cavitate, I can bleed off what I don't need and run it back to tank along with the scavenge return.   As the model is set up with 7 spray nozzles, I can throttle delivery with a regulator dumping back to tank

Quite right; sounds like an excellent plan.

Cheers  :cheers:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 26, 2023, 01:57:49 PM
I'd rather be looking at it  ( oil pressure) than looking for it!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 27, 2023, 12:51:42 AM
OK   I don't mind saying they gave me a fight, but their smooth as buttah!

Oil and scavenge pump main bodies and gears in process.    2 more ops on each of the bodies and I need to put keyways in the gears

But good progress!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Dave Otto on February 27, 2023, 01:00:43 AM
Amazingly tiny, nice work Dave!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 27, 2023, 01:06:28 AM
Amazingly tiny, nice work Dave!

Dave


Well lets see if I can get the .03" keyways in!      I may do half rounds with a pin as a key
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on February 27, 2023, 11:02:19 AM
Looking good  :ThumbsUp:  It has steel gears in a brass/bronze body I think so thermal expansion shouldn't be a problem. The first cooling water gear pump I built used plastic gears and the thermal expansion caused it to sieze.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on February 27, 2023, 11:11:23 AM
Those Pumps are tiny (but look great)  :praise2: - are the shafts 1/8" Mill/Drill-Bits (or rather where) ?

Per               :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 27, 2023, 12:39:17 PM
Those Pumps are tiny (but look great)  :praise2: - are the shafts 1/8" Mill/Drill-Bits (or rather where) ?

Per               :cheers:

For the moment yes they are.  .for the moment..
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 27, 2023, 12:44:25 PM
Looking good  :ThumbsUp:  It has steel gears in a brass/bronze body I think so thermal expansion shouldn't be a problem. The first cooling water gear pump I built used plastic gears and the thermal expansion caused it to sieze.

Yup   just following big practice    though the 917 used magnesium....of course....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: vtsteam on February 27, 2023, 01:41:28 PM
I love the pumps. :ThumbsUp: :ThumbsUp:

I've got some magnesium. I always check donated scrap aluminum for melting by cutting off a sliver and trying to light it. Very occasionally it will be magnesium and burn white. I don't want any in my furnace for obvious reasons. The largest piece I have is a VW engine crankcase, which I'd hoped would be a good source of aluminum. But, nope.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 27, 2023, 02:07:25 PM
I love the pumps. :ThumbsUp: :ThumbsUp:

I've got some magnesium. I always check donated scrap aluminum for melting by cutting off a sliver and trying to light it. Very occasionally it will be magnesium and burn white. I don't want any in my furnace for obvious reasons. The largest piece I have is a VW engine crankcase, which I'd hoped would be a good source of aluminum. But, nope.

Yup   No magnesium in my shop    don't need it..and I live there so don't want the risk.

You really need to keep seperate waste storage for it plus the correct types of fire fighting equipment.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 27, 2023, 03:54:41 PM
I love the pumps. :ThumbsUp: :ThumbsUp:

I've got some magnesium. I always check donated scrap aluminum for melting by cutting off a sliver and trying to light it. Very occasionally it will be magnesium and burn white. I don't want any in my furnace for obvious reasons. The largest piece I have is a VW engine crankcase, which I'd hoped would be a good source of aluminum. But, nope.

Yup   No magnesium in my shop    don't need it..and I live there so don't want the risk.

You really need to keep seperate waste storage for it plus the correct types of fire fighting equipment.

Some titanium bar found it's way into my shop disguised as steel bar. Gave the cutter in the lathe a shock, when they took a test cut.

It's great stuff for making sparks on the grinder.      But that's it    :zap:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jan D on February 27, 2023, 09:18:05 PM
Porsche had good firefighters, I guess..  :)
All cast parts of the engine except cylinders and heads are magnesium. Even something like the housing for the rev counter gear.

Ah, and quite a few titanium parts as well... Connecting rods, rod bolts, upper shaft driving the distributors and fan... Lower "output" shaft, except on the first few engines... And all of the studs and screws (except the main M12 ones which holds the housing together, and the M10 "housing to cylinder head" ones, these are Dilavar). Intake valves for "short duration races" (not Le Mans) were titanium as well.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on February 27, 2023, 09:53:03 PM
Honsel Werke were the masters of magnesium casting and Otto Fuchs did the titanium forgings. Crankshaft by Alfing...trivia.....but not trivial work.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 28, 2023, 08:11:22 PM
Porsche had good firefighters, I guess..  :)
All cast parts of the engine except cylinders and heads are magnesium. Even something like the housing for the rev counter gear.

Ah, and quite a few titanium parts as well... Connecting rods, rod bolts, upper shaft driving the distributors and fan... Lower "output" shaft, except on the first few engines... And all of the studs and screws (except the main M12 ones which holds the housing together, and the M10 "housing to cylinder head" ones, these are Dilavar). Intake valves for "short duration races" (not Le Mans) were titanium as well.

They probably did have good firefighters!    A bit hard to justify on a hobbyist budget.  And that is one surprise I can live without.  Ive seen that happen and it's always a mess to clean up if you're lucky!

The nice thing about most machinery and tool steels is that they can be processed with a home shop,   With the 917 crank for instance, I would have to send it out for hobbing, and preferably ground if possible and the cost would be thousands on a good day.     Where as a multipiece BB crank with hardened steel crank pins ball bearing mains allows a milled gear and other components that are comparatively easy in the home shop.  Much to be said about the satisfaction of making it in my shop, and I gain a great deal of satisfaction figuring out new means for new problems.    It will look very much like the real deal when I'm done, and it will be me who did it.    And that is the Journey Mike (Vixen) talks about. 

Though I think I'll have to come up with something made out of Titanium on this build..... :ROFL: :thinking:

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on February 28, 2023, 08:44:41 PM
I suppose that you could buy a Titanium bolt or two for the Engine - if you still feel that way  :mischief:

Per    :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 28, 2023, 09:12:13 PM
I suppose that you could buy a Titanium bolt or two for the Engine - if you still feel that way  :mischief:

Per    :cheers:

buy a Titanium bolt or two for the Engine????? 

A few moments ago Dave said " Much to be said about the satisfaction of making it in my shop, and I gain a great deal of satisfaction figuring out new means for new problems.    It will look very much like the real deal when I'm done, and it will be me who did it.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 28, 2023, 10:51:25 PM
I suppose that you could buy a Titanium bolt or two for the Engine - if you still feel that way  :mischief:

Per    :cheers:

buy a Titanium bolt or two for the Engine????? 

A few moments ago Dave said " Much to be said about the satisfaction of making it in my shop, and I gain a great deal of satisfaction figuring out new means for new problems.    It will look very much like the real deal when I'm done, and it will be me who did it.

Wot Mike said!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 01, 2023, 12:21:43 AM
made the last 2 housing parts for the oil and scavenge pump assembly.   I then ran it in on the lathe with lots of oil

Next I need to make the 2 1/8" shafts with keyways for the gears....and put keyways in the gears.   I've got a cunning plan for this...stay tuned!

I'd like to have this pump running by the end of the weekend.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on April 01, 2023, 04:50:55 AM
That's pretty small, Dave!  Can't wait to see it all together  :ThumbsUp: :popcorn:
Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on April 01, 2023, 05:52:34 PM
That's a tiny pump  :praise2: Fuel injection should be no problem for you  :)  ::)  :wine1:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 01, 2023, 10:20:22 PM
I'm setting up to cut these keyways.... the bore is .125"  ( 3.175 mm)

The keyway is 0.0468"     The Key is a piece of .0468" diameter dowel pin.   I'm going to use the lathe mounted keyway cutter I built for the Logan,

 ill need to make a cutter ::)

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on April 01, 2023, 11:28:50 PM
Great work on such a tiny assembly !
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 02, 2023, 12:55:52 AM
Not particularly happy with the cutter I made....I'll remake it tomorrow.....but making progress...

Vixen's experimental gears in the foreground....for size comparison.....   I'll get there.....but I'm bushed right now....

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 02, 2023, 09:17:32 PM
Key way cutting attachment set in the lathe to finish the keyway in the pump gears.  I ground up a better HSS single edge cutter to cut the keyway, and I've mounted it in a 1/2" shank holder and I'm waiting for the loctite to kick off.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 15, 2023, 12:54:35 PM
3D printed the engine.blocks yesterday and gave it a whirl   worked nice!

https://www.youtube.com/watch?v=I965XWwQRZw


https://www.facebook.com/100008022455617/posts/pfbid09kCQYLxiFbcHdhNhJwnstxmB4r3JspfG4iXYcti4vZxYdvfub7Exw8qfWTSsZYrTl/?app=fbl\
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 15, 2023, 01:19:14 PM
Next step now that the dbit grinder work head is done is to get the grinder running and make a keyway broaching tool that is accurate........fixing a tool to mKe a tool...

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on April 15, 2023, 02:06:04 PM
Is the printed block just a test piece or is it going to be used for casting from?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 15, 2023, 03:00:22 PM
Just a fit check, and a bit of inspiration for next steps

I will hopefully get the pump done shortly.....from there the "throttle" on the 917 project will probably lift a bit to take advantage of the next 4 months of decent weather and get my boat back in the water.....    During that time, I'll be in the shop on the wet weekends and evenings if I'm not trying to get Rushforth back in.   

One of the key tests I need to complete though is to confirm the pump performance up to 4000 rpm or half engine speed ( expected anyway)  this will confirm the pump drive gear ratio, and that will help finalize the block halves.     The material for the blocks is in the shop  ( 6061-T6)  and they will be machined from billet and then line bored on the lathe.

The finishing of the grinder workhead was the first line boring job I've done on the SouthBend since I rebuilt her.   It proved that she bores DEAD straight....like I'm incapable of measuring any variation in the 1.25" bore over nearly 3 inches...so less than 0.0002" taper ....as I can't measure a bore anymore accurate than that.....so that was a good validation for the engine block work that is coming

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on April 15, 2023, 05:35:20 PM
That's pretty cool, Dave!  Nice to see all your work fitting together, even if only for demonstration purposes!  :popcorn:

That will be fun to see your boat back in the water with its new engine.  Make sure and let us know how it goes.

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 15, 2023, 06:05:03 PM
That's pretty cool, Dave!  Nice to see all your work fitting together, even if only for demonstration purposes!  :popcorn:

That will be fun to see your boat back in the water with its new engine.  Make sure and let us know how it goes.

Kim
Thanks Kim,   the boat hasn't been used much in the last 7 years after my daughters first diagnosis.     The engine conversion started just before the second diagnosis and right before the pandemic...so it will be nice to get the boat back into use again!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 29, 2023, 09:21:31 PM
OK   fix a tool to make a tool to go in another shop made tool to cut a little keyway...........yup....

Fix the 265 grinder to make a .05" keyway broach, to go in my lathe mounted keyseat cutter

The grinder did a nice job!   Super easy to grind that....that would be really hard to do by hand....the shank of the tool is 0.125"

I'm setting back up to finish the keyways in the driven oil pump gears.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on April 30, 2023, 01:18:51 AM
Looks like your rebuilt 265 did a nice job grinding that tool!  :popcorn: :ThumbsUp:

Looking forward to seeing it make the keyways now!

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 30, 2023, 05:34:31 PM
Cutting the keyways in two gears
Bore is 1/8"

https://youtube.com/shorts/amzrIlNX7nc?feature=share


Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on April 30, 2023, 07:01:52 PM
That's great, Dave! Love seeing your keyway cutter in action!  :ThumbsUp: :popcorn:

Kim

Just as an aside - if you don't want your video to come out as a Youtube Short, try recording it in landscape mode rather than portrait mode.  I found that makes it less likely to be a short.

I also have learned that if you use some other recording device than a phone it won't come out to be a short.  But phones are what we all have that do videos.  Luckily, my camera also happens to have a video mode and those videos never get converted to shorts!  Just my experience.  And personally, I don't like the shorts because you can't embed them in the forum posts.  Just link to them, as you've found.  I find their stupid 'short' thing very frustrating. But I think it's just YouTube trying to compete with TicToc... go figure...  But maybe it isn't something that bothers you, which is fine too!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on April 30, 2023, 07:16:14 PM
Yeah it's a bit of a pain in the ass, but it works for what I'm trying to do ....other than the embedding part....
IThe gears are done, and next is the keys and I need to tap a few holes and I also have a cross pin slot to cut in the drivegear to the pump.     Fussy part with a lot of ops     I also need to get the cross port holes drilled.

Tonight I need to make a few parts for work....so that has me distracted at the moment......and it's about to start raining cats and dogs

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on June 09, 2023, 11:14:20 PM
Well    I've worked 27 of the last 32 days, near 80 hour weeks....and I'm off this weekend....finally.

Unfortunately long hours wasn't working on this project!

I may get some time in the shop tomorrow, and I'll try to pick back up on the pump....and try to finish it.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on June 10, 2023, 12:02:03 AM
Ouch!  Glad you are back to some play time!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on June 10, 2023, 09:58:08 AM
Man - that is a hard program .... you certainly earned som R&R - so enjoy  :cheers:

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on June 10, 2023, 07:24:24 PM
Glad your back on model making  :ThumbsUp:  :ThumbsUp: but I know from my friends in Dracut that good people are almost impossible to find at the moment  ::) 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on June 11, 2023, 12:12:38 PM
Some motivation....

https://www.youtube.com/watch?v=XpcTAL6Ogqk

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 03, 2023, 05:29:40 PM
Productive 2 days!

The pump is together, and I've ran it in a test stand at 4000 rpm for an hour....see video of the set up

It pumps approximately ( by estimate only....I've not measured it yet)  .8 liters a minute at 4000 rpm.    All seems good!

https://www.youtube.com/shorts/iLhpYt9hjyU


Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 03, 2023, 05:33:16 PM
The gear pump calculations to estimate flow.

Pressure has not been measured, but I can't stop the flow with my finger.....so enough to flow through the engine.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on July 03, 2023, 05:43:13 PM
Great little pump, Dave!  It really seems to be moving the water!  :ThumbsUp: :popcorn:

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 03, 2023, 05:49:08 PM
Great little pump, Dave!  It really seems to be moving the water!  :ThumbsUp: :popcorn:

Kim
Thanks Kim!

Actually low viscosity oil.    Pumps really well!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on July 03, 2023, 05:53:38 PM
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :ThumbsUp: :ThumbsUp: :ThumbsUp:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 03, 2023, 06:02:46 PM
I didn't see anything that even remotely looked like cavitation.    I saw some air in the oil pump side under operation, but the inlet is so close to the surface of the oil I think it was just drawing in air.    Regardless....4000 rpm is considered maximum   ( 8000 rpm engine speed) and it ran like a little watch with no issue for an hour..   I'd like to measure the flow, and hopefully the pressure available, but I think I can live with the gearing as is.   That was the last unknown for the internals of the engine block.   So I can finalize the engine block and get it machined!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on July 03, 2023, 06:10:31 PM
Excellent!   Looking forward to seeing how the block is done.   :popcorn: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on July 03, 2023, 06:46:27 PM
Great test result Dave  :praise2:

I must admit to ignorance in regard to how much pressure is needed in any Smooth Preasure Bearing ....
But considering that you don't plan to run it with a load - I will be very surpriced if this isn't far beyond requirements  :cheers:

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 03, 2023, 06:50:39 PM
Great test result Dave  :praise2:

I must admit to ignorance in regard to how much pressure is needed in any Smooth Preasure Bearing ....
But considering that you don't plan to run it with a load - I will be very surpriced if this isn't far beyond requirements  :cheers:

Per

The outlet port is .09"   or just over 2mm......when I close it off with my finger , I can't stop the flow....so at least 10PSI.....probably much more....that said, as I'll be running splash or more accurately a spray bar aimed at the big ends of the conrods....I think that most of it will be diverted back to to the oil tank.     10 psi is all the pressure I need to make a spray bar work great...

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: petertha on July 04, 2023, 08:11:22 PM
Dave, your oil pump assembly is a work of art! If I go too deep in the weeds with my newbie questions, just let me know. I don't want to detract the build post. Maybe offline is better.

- I looked at your spreadsheet just a bit. Some input parameters look vaguely familiar to articles I've downloaded but never managed to piece together much of anything even as a rough sizing tool. I pretty much had given up & started looking over other model pumps to plagiarize & cross my fingers. Yours is MUCH more detailed. Can you elaborate on how you put this together? Have you been down this design path before on other model engineering projects or was it this particular (Porsche) task that triggered its development?

- Am I correct in assuming the Lubrication & Scavenge pump design formulas are identical (from your spreadsheet) but W (gear width) is different to yield different flow rates & pressures? Lubrication = 0.56 l/m @ 10 psi vs Scavenge = 0.87 l/m. at 5 psi Is there some kind of rule of thumb that says scavenge should be +50% more or something?

- I suspect the annular gap between gear OD & housing cavity ID is tied up between the L&D terms, but can you give me a ballpark figure of what your annular gap measures?

- I'm told that this 'intersection area' where the gears come together & depart is quite important. Would you agree? Maybe I missed but I didn't see any dimensional reference to its shape & its not really shown on the inset sketch. Can you elaborate?

- When you calculate torque & power, are you looking at this as some percent of engine output power, kind of like a necessary parasitic cost of lubricating because they are mechanically driven?

My radial engine is premix oil in nitromethane, so essentially mist lubrication. I might be pushing the limits of what that accomplishes, so I told myself 'next' engine will have oil pumping system. I wanted to take some baby steps & build a mockup test pump similar to your test bath apparatus. Gear cutting anything that small I suspect is above my pay grade so was looking at thinning commercial spur gears. Should I expect some lower performance vs. 'designed' gear lobe profiles. Would I be looking at 'true-ing' or lapping the gear OD to make them suitable for pump gears?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 04, 2023, 09:32:37 PM
Becoming more plausible every day!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on July 04, 2023, 09:34:46 PM
3d printed?  Are you going to cast the block?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 04, 2023, 09:57:00 PM
3d printed?  Are you going to cast the block?

No, but I'm using the 3D printed blocks be a stand in for fit checks...I'm trying to prefit everything prior to machining the block from billet.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 04, 2023, 10:34:36 PM
Dave, your oil pump assembly is a work of art! If I go too deep in the weeds with my newbie questions, just let me know. I don't want to detract the build post. Maybe offline is better.

- I looked at your spreadsheet just a bit. Some input parameters look vaguely familiar to articles I've downloaded but never managed to piece together much of anything even as a rough sizing tool. I pretty much had given up & started looking over other model pumps to plagiarize & cross my fingers. Yours is MUCH more detailed. Can you elaborate on how you put this together? Have you been down this design path before on other model engineering projects or was it this particular (Porsche) task that triggered its development?

- Am I correct in assuming the Lubrication & Scavenge pump design formulas are identical (from your spreadsheet) but W (gear width) is different to yield different flow rates & pressures? Lubrication = 0.56 l/m @ 10 psi vs Scavenge = 0.87 l/m. at 5 psi Is there some kind of rule of thumb that says scavenge should be +50% more or something?

- I suspect the annular gap between gear OD & housing cavity ID is tied up between the L&D terms, but can you give me a ballpark figure of what your annular gap measures?

- I'm told that this 'intersection area' where the gears come together & depart is quite important. Would you agree? Maybe I missed but I didn't see any dimensional reference to its shape & its not really shown on the inset sketch. Can you elaborate?

- When you calculate torque & power, are you looking at this as some percent of engine output power, kind of like a necessary parasitic cost of lubricating because they are mechanically driven?

My radial engine is premix oil in nitromethane, so essentially mist lubrication. I might be pushing the limits of what that accomplishes, so I told myself 'next' engine will have oil pumping system. I wanted to take some baby steps & build a mockup test pump similar to your test bath apparatus. Gear cutting anything that small I suspect is above my pay grade so was looking at thinning commercial spur gears. Should I expect some lower performance vs. 'designed' gear lobe profiles. Would I be looking at 'true-ing' or lapping the gear OD to make them suitable for pump gears?

Hey Petertha,

When I worked at Moore Tool, I was a lead designer for new diamond turning lathes.   As such there was a LOT of work to be done sizing the hydraulic system and all of the associated components!    That was a while ago, but I got pretty familiar with the servo driven gear pumps we used for all the hydrostatic slides and spindles.   I created this very detailed system model of the hydraulic system back then and I went back and grabbed a copy of it and modified it to do some of the pump calcs here.    Now the concern I have with this little pumps, is that all the associated white papers on the subject are for the 1 to 1 scale pumps, and honestly, how the oil is going to handle going through a pump at 4000 rpm when the gear has a .25" PCD....lord only knows!      If you calculate the reynolds number, there shouldn't be any issues with flow, but again, most of the existing knowledge is regarding pumps MUCH larger.     So I did much the same as you did, and looked at other engines out there.    They Edwards R5, and Ron Collonna's Offy were both pretty close in engine displacement, and the pumps are very similar in size to mine.     I went up about 50% of so for the scavenge pump so it's always pulling more oil than the supply is delivering.    the driving limit here is at the size I made mine, it's getting tough to put one together with all the stack tolerances.    It's doable!   Just not easy.
At this small size, it would appear that I have WAY more oil than I'll need with a spray lube system, so I'll count on being able to put most of it back in the oil tank.

Most of the RC engines in this size run with nothing more than the oil mixed with the fuel, and allowing blow by to do all the work.    So I think if I provide anything, I'll be way ahead.

As a reference I've attached a gear pump design guide that I found online.    The blurb about the approximate delivery flow rate I cut and pasted out of an article, and I'm trying to dig it up currently. Also attached a snap of one of my lathes.    I designed the headstock and tailstock spindles for a max working load of 3000 kg  (6600 pounds)    As a load test we rented a very large piece of steel round stock that was north of 7000 pounds.   The 4 jaw chucks are 24" in diameter for reference.    Yes they took the load and had an asynchronous runout in the low nanometers range.....fun times!

https://apps.dtic.mil/sti/pdfs/AD1169714.pdf
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 04, 2023, 10:53:41 PM
- Am I correct in assuming the Lubrication & Scavenge pump design formulas are identical (from your spreadsheet) but W (gear width) is different to yield different flow rates & pressures? Lubrication = 0.56 l/m @ 10 psi vs Scavenge = 0.87 l/m. at 5 psi Is there some kind of rule of thumb that says scavenge should be +50% more or something?

- I suspect the annular gap between gear OD & housing cavity ID is tied up between the L&D terms, but can you give me a ballpark figure of what your annular gap measures?

- I'm told that this 'intersection area' where the gears come together & depart is quite important. Would you agree? Maybe I missed but I didn't see any dimensional reference to its shape & its not really shown on the inset sketch. Can you elaborate?

- When you calculate torque & power, are you looking at this as some percent of engine output power, kind of like a necessary parasitic cost of lubricating because they are mechanically driven?






The widths of the gears will drive the flowrate.  Pressure depends on what is down stream from the pumps.

As far as annular gap.    As small as you can get away with!....   .002" is probably a good number...and while that sounds loose, it's not.  There are a lot of stack tolerances working against you

As far as the intersecting area for flow I made it as wide as 2 tooth spaces.   

As far as power number in the calculation,   It's based on an assumed delivery pressure of 10 psi.    I don't really know what the delivery pressure  will be actually, but I can calculate the load of 6 nozzles if I know the sizes and go from there.    For the moment I'm assuming a 10 psi flow and a pretty terrible efficiency.    like in the 80 percent range or less....    What ever I get that is over this I'll pump back to tank.

I calculated the power as I wanted to get a feel for the load on the pump....it's small....so I'm not too worried about the drive gears    I suspect the losses from friction of the engine bearings and rings to be much higher than the loss to pumping the oil....To mimize the parasitic friction I ran the pump in on the mill for 3 hours....at high speed and get it bedded in and smooth....that seemed to work well as it's very easy to turn over but appears to be pumping thin oil quite easily

And again that volume calculation is a "Swept volume" number and doesn't account for slippage or leak by.    it's just an estimate

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 05, 2023, 01:53:50 AM
Would I be looking at 'true-ing' or lapping the gear OD to make them suitable for pump gears?
Modify message




Hey Petertha,   No I did not lap the gears...  I spent a lot of time carefully setting them up on an arbor, turning them and cutting the teeth concentric.   That was all that was required.
Less than .0004 runout...

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 05, 2023, 03:33:13 AM
Would I be looking at 'true-ing' or lapping the gear OD to make them suitable for pump gears?
Modify message




Hey Petertha,   No I did not lap the gears...  I spent a lot of time carefully setting them up on an arbor, turning them and cutting the teeth concentric.   That was all that was required.
Less than .0004 runout...

Dave

Nothing like a good dividing head that shares spindle tooling with the lathe specifically for making fussy little gears...    It's a little Hardinge, with a 3C collet  ID and a 1.320-12 spindle thread.   I spent quite a bit of time cleaning this up and setting it straight, and I can transfer work from the lathe right to it and be under .0004" runout pretty easily.   I have a dedicated Hardinge 1/2" collet that  is specifically for the transfer operations.   It drops in my mill vise and is ready to go in about 30 seconds.   I made new plates, a new index pin, adjusted the spindle play, and internally the spindle is perfect   It wasn't used very much.    It was made in the 30's .

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 05, 2023, 03:40:48 AM
https://www.modelenginemaker.com/index.php/topic,11160.0.html

https://www.modelenginemaker.com/index.php/topic,11232.0.html

Heres the rebuild threads of the dividing head...

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 16, 2023, 05:51:37 AM
This will be an interesting part to make........  Cooling fan bearing mount.

I'll probably make it as a "stacked cake " assembly....then it's not too bad.

Oil pump is done...though I still need to determine available pressure...

Coming right along now.....I should have some pictures tomorrow...

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Jasonb on July 16, 2023, 07:04:42 AM
Well they did not make it easy for you to machine by including those raised bosses on the six holes.  >:( And looks like you will be needing a long reach ball nose tool for the fillets.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 16, 2023, 02:58:45 PM
Oh it will be a two piece assembly for sure.  The original was a casting, which makes it pretty easy......

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on July 16, 2023, 04:19:02 PM
Pretty complex piece, looks a lot like the prop holder for an airplane.   :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on July 16, 2023, 04:51:51 PM
Hello Dave,

That looks like a nice, interesting piece to make next.   :ThumbsUp:

What are you planning to do about the fan and it's shroud? A 3D print, painted to resemble the cream coloured glass/epoxy dough mouldings they used back in the 60's, would look good.

Cheers

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 16, 2023, 07:11:41 PM
Hello Dave,

That looks like a nice, interesting piece to make next.   :ThumbsUp:

What are you planning to do about the fan and it's shroud? A 3D print, painted to resemble the cream coloured glass/epoxy dough mouldings they used back in the 60's, would look good.

Cheers

Mike



Possibly.  I may opt for a carbon fiber reinforced 3D printed part..    The fan is about the right size....but it needs some more features....I'm working on some of the external detail of the block and some of the sub systems..

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on July 16, 2023, 07:41:33 PM
Looking forward to seeing what you come up with and how you do it!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 16, 2023, 08:59:22 PM
This is how Id make this part....

Showing the  2 pieces prior to assembly with loctite.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on July 16, 2023, 10:28:01 PM
That looks like a great solution Dave  :ThumbsUp:   :cheers:

Per
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 17, 2023, 02:20:09 AM
Current state....everything moves nicely!....with the real one...

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Don1966 on July 17, 2023, 05:19:32 AM
Love it bud!

Don
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on July 17, 2023, 06:27:44 AM
That is mighty slick looking, Dave!  :ThumbsUp: :popcorn:

I like the printed crankcase you're using to test everything in.  Very clever!

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: cnr6400 on July 17, 2023, 02:49:44 PM
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Brendon M on July 19, 2023, 08:29:06 AM
Looks amazing :)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on July 19, 2023, 12:42:56 PM
Dave, do you have one of the original engines? Or just the pictures of one?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 19, 2023, 03:21:48 PM
Dave, do you have one of the original engines? Or just the pictures of one?


Lol   if I had an original I'd pay someone to make the model     no just pictures ...
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: petertha on July 19, 2023, 07:53:32 PM
Dave, maybe I missed the detail somewhere between your initial design post & the current build post, but what is your plan in terms of the ignition system? Maybe I have it wrong but thought you were considering glow plugs for testing/simplicity, but could be substituted with spark plugs on common 1/4-32 thread? Also with the oil pump design & performance now vetted, I assume you will go with oil control piston rings (or maybe that was the plan all along?) Sorry for jumping ahead, its all very exciting watching this unfold.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 19, 2023, 08:14:04 PM
2 rings.   Bottom one set as a oil scraper.    Most of the oil ...IThink  will be bypassed to tank...but we will see

As for ignition, I will be starting with glow plugs and progress to spark plugs.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 27, 2023, 05:24:10 PM
This is soooooooo cool    Fusion 360 scanning solution

https://www.youtube.com/watch?v=39Jmh-tqQBo
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on July 27, 2023, 06:54:17 PM
That ability to  bring in canvas image has been there a long time. I've  used it to outline things like cockpits and cabs for RC models, as well as animals for carving. It does depend on the camera being square to the object and far enough away not to get lens distortions or parallax.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: stevehuckss396 on July 27, 2023, 08:13:51 PM
Back in 2018 we were in Zanesville for the show and I talked Paul into arrainging a shop tour of Saunders Machine Works. Very impressive for a small shop and spotless. Super nice guy. Then we talked Paul into touring his shop. A little less clean. I felt more at home there!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on July 27, 2023, 09:49:10 PM
That ability to  bring in canvas image has been there a long time. I've  used it to outline things like cockpits and cabs for RC models, as well as animals for carving. It does depend on the camera being square to the object and far enough away not to get lens distortions or parallax.

Yes and I used it originally with the 917 build..but now you can CALIBRATE  the image ...that was the key thing.....that's awesome!!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on July 27, 2023, 10:00:23 PM
That ability to  bring in canvas image has been there a long time. I've  used it to outline things like cockpits and cabs for RC models, as well as animals for carving. It does depend on the camera being square to the object and far enough away not to get lens distortions or parallax.

Yes and I used it originally with the 917 build..but now you can CALIBRATE  the image ...that was the key thing.....that's awesome!!

Dave
Ah, yes, thats new! 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 22, 2023, 02:42:13 PM
Ah    the weather is changing....back inside I go.     I think wrist pins will be next.    Engine block is coming up though.

The oil and scavenge pump tested well, though I'd like to see what pressure I can expect and at what flow rate, so that test may happen soon,

But I'm done for the season with the boat project.....  Back inside.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on October 22, 2023, 03:12:23 PM
Great to see you back on the engine, looking forward to the next parts. I take it the storms didn't flood you out and make you take to the boat? You guys had some dreadful rainfalls there, last time I went up to Maine there was another one I drove through.
 :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on October 22, 2023, 07:06:57 PM
we got 11" of rain in 4 hours or about 3 months of rain in an afternoon.     My house was OK....only because I have prepped the house for such things over the years.    My neighbors got hit hard  ( 3 feet of water in their basements)     

On to the 917!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 04, 2023, 11:19:47 PM
A bit of work done yesterday.   I'm making the fan shaft support housing.    As the original was a magnesium casting, I'll have to make it in 2 pieces and bond it together to get the details I'm looking for.    Here's the upper half and some pictures of what I'm getting on with here.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Mike R on December 05, 2023, 12:11:45 AM
Looking good so far Dave.  Do you have more than that picture to work from? 
In that picture the fingers or arms seem to protrude past the round flange, as you can see the bolts poking up aren't concealed by the flange.
I'm not sure what the design is supposed to be and how it attaches so maybe not important?

Regards,
Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on December 05, 2023, 12:23:44 AM
Wow, lots to just that one little piece, great to see you back at this one!    :popcorn: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 05, 2023, 12:29:32 AM
Looking good so far Dave.  Do you have more than that picture to work from? 
In that picture the fingers or arms seem to protrude past the round flange, as you can see the bolts poking up aren't concealed by the flange.
I'm not sure what the design is supposed to be and how it attaches so maybe not important?

Regards,
Mike

Here's a couple of pictures of the part.    Im building it as 2 parts and then bonding the 2 parts together.   It's not possible to machine the features in, in one piece as the original was a casting.    I'm not adding the vertical ribs on the housing.   I circled the part in red on the prototype engine.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 05, 2023, 12:38:27 AM
I have a few more pictures, but they are not mine to share, but yeah....All I have is some basic dimensions and photographs to go by.   I'll do the best I can with that but it's coming   I superimpose pictures over the cad geometry and do my best to match it up using the known bore and stroke as a gage.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on December 05, 2023, 12:42:14 AM
That's some real pretty maching, Dave!  :ThumbsUp: :popcorn:

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 05, 2023, 01:28:47 AM
Looking good so far Dave.  Do you have more than that picture to work from? 
In that picture the fingers or arms seem to protrude past the round flange, as you can see the bolts poking up aren't concealed by the flange.
I'm not sure what the design is supposed to be and how it attaches so maybe not important?

Regards,
Mike

The part is the bearing housing for the main cooling fan for the engine.    The 917 is an Air cooled engine.    That large menacing fan connected to the engine pulls air down and through all the cylinders.   The fan turns at engine speed so up to about 8200 rpm.     It's moving some air for sure!   On the model it's about 75mm or 3 inches in diameter.    On the prototype, it was a composite fan, while on the model, I may go carbon fiber reenforced 3D printed, but I suspect it will end up aluminum cut from billet.    That way I KNOW it won't come apart at full song.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 05, 2023, 01:45:53 AM
Here's a section view....one of the few drawings I have....which is widely available on the web
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Mike R on December 05, 2023, 02:27:17 AM
Thanks for the explanation Dave and the additional details and pictures.
Looks like the bearing housing also is the support and centering mechanism for the fan shroud. 

Pretty amazing they were using composites for what I'd call a performance critical engine components in late 1960s.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 10, 2023, 01:11:42 AM
Working on the 917 model building from the inside out. Next bit is the fan drive The 917 was air cooled.and had a big engine driven fan on top of the engine. Tonight I machined the fan bearing housing shown mounted top center in a 3D printed block half. I'll bead blast it so it looks more like the casting it was. Once all the various drives and internal gear trains are built and together I'll machine the billet block which is split down the middle with 7 main bearings. Progress!

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on December 10, 2023, 02:00:26 AM
That's a nice looking piece, Dave! Must feel good to be forging (machining?) ahead again. :ThumbsUp: :ThumbsUp:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on December 10, 2023, 02:01:07 AM
Wonderful!    :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on December 10, 2023, 05:20:30 AM
Beautiful part!  Nice to see you getting some time to work on it, Dave!  :ThumbsUp: :popcorn:

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Admiral_dk on December 10, 2023, 08:08:38 PM
Completely agree - nice to see great parts being made for this Historic Engine again  :cartwheel:

Have you blackned the Block (or is it a 3D Print) Dave ?

Per        :cheers:              :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 10, 2023, 08:35:37 PM
Completely agree - nice to see great parts being made for this Historic Engine again  :cartwheel:

Have you blackned the Block (or is it a 3D Print) Dave ?

Per        :cheers:              :popcorn:

That's a 3D Print for test fits.    Just fit checks.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 17, 2023, 07:17:16 PM
Progress  photos

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on December 17, 2023, 07:26:27 PM
Looking good Dave

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on December 17, 2023, 08:19:45 PM
Great!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 17, 2023, 08:26:24 PM
Thanks guys

I'll keep going with the various drives until they are all populated.   From there, I'll be able to get into cutting the blocks.

Though I am tempted to make this next....because......fan!

The blades on the real one have some twist to them.   This one is based on a successful ducted fan aero plant but with half the blades removed.    To really make it match it needs the blade twist......I'll work on my F360 kung fu and see if I can loft a suitable fan blade in.      The real one was a fiberglass layup, and Porsche has had trouble to this day getting them made..... for the model, running at 8000 rpm...in a crowded exhibit hall, I VERY MUCH want it to stay together!....and not go flying off like a lethal Frisby being hurled from"top job"..... Odd Job   So I'll make it from aircraft aluminum, and get it anodized the correct color.     

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on December 17, 2023, 09:12:04 PM
"Oddjob"  was that characters name.  He would top you with his hat, though!   :paranoia:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 17, 2023, 09:28:04 PM
"Oddjob"  was that characters name.  He would top you with his hat, though!   :paranoia:

Thanks Chris....duly noted and corrected....
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on December 17, 2023, 10:33:31 PM
Love seeing the progress, Dave!

And I'm betting you can figure it out in Fusion!  I've been playing around more with Fusion 360 and boy, is it powerful!  I get lost in all the things it can do - and to make it more confusing, most of the features have multiple modes - sketch, solid, etc.  I'm working my way through more YouTube videos.  When you only play with it every few years, it's easy for that stuff to slip away! But I'm hoping to work up to a better mastery of it over time.

You're clearly WAY beyond my F360 kung-fu.  I hope to get my yellow belt soon! :)
Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: cnr6400 on December 17, 2023, 11:02:35 PM
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :popcorn: :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Tennessee Whiskey on December 18, 2023, 11:40:48 PM
Oh dear Lord, how long is going to take, I’m old  :stickpoke. Cletus wants to hear Vrooooom  :lolb: :lolb: :lolb:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 19, 2023, 09:28:11 AM
Oh dear Lord, how long is going to take, I’m old  :stickpoke. Cletus wants to hear Vrooooom  :lolb: :lolb: :lolb:

Me too!

 :DrinkPint:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 29, 2023, 02:10:09 AM
Been sick all week of my vacation.....which kinda sucks....but I'm a little better today

I'm programing the blocks currently, and doing some cleaning, reorganizing the controls on the Tormach to make some more room ergonomically, making a index plate for angular indexing 36 hole count, and mouting up a 4' 4 JAW for the dividing head completion of tooling.

Puttering....but I did get something done.....   A doctor's appointment for my daughter tomorrow, and then hopefully some shop time.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Kim on December 29, 2023, 05:34:39 AM
Sorry to hear you haven't been feeling well, Dave.  Glad you're on the mend and getting some shop time!

Hope things go well at your daughters Dr appt tomorrow!

Kim
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: gadabout on December 29, 2023, 06:33:19 AM
That’s a BIG 4 jaw!!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on December 29, 2023, 05:57:17 PM
That’s a BIG 4 jaw!!

LOL    yeah   4"

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 14, 2024, 02:47:08 PM
Some more progress....or maintaining some patience.

Cam timing

I'm going with the same valve timing as the OS FS26 including valve size and lift numbers  ( thanks Peter for compiling that!)

8mm valves
2.35mm intake lift
2 mm exhaust lift

I'm fine tuning the valve, valve cage , lifter bucket, retainer designs but it's looking really good with enough room to do what I want and it's makable.

I'm fairly convinced I need to vent the lifter buckets so they don't get inhibited by pumping issues.   

I have a set of used FS26 valves and valve springs coming as reference  ( found them cheap on the bay).   

Dave



Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 14, 2024, 02:53:14 PM
Cam shaft drives

the more I think about this assembly, the more I like bronze bearings in this assembly.   If I have a small ball bearing come apart here, it will FOD out the entire engine with hardened balls in all the gears.   They have no where to go but into the gear train.....

I don't like that at all!    I'll be using bronze bushes here, as the load will be small, the oil lubrication ample.    I'll keep the OD of this bushings as small as possible to keep the friction down.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 14, 2024, 03:18:54 PM
Additionally I was able to "dry fit" the fan drive gears and confirm things.   So I'm very near cutting engine blocks!   :cartwheel:

things will take off from there.    That will clear the decks for a lot of progress.

Now the caveat.....

I'm getting busier at work.....and I know I'll be spending  a lot of overtime there.   be patient everyone.   but I'll be working on it for sure

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 14, 2024, 04:12:01 PM
Cam shaft drives

the more I think about this assembly, the more I like bronze bearings in this assembly.   If I have a small ball bearing come apart here, it will FOD out the entire engine with hardened balls in all the gears.   They have no where to go but into the gear train.....

I don't like that at all!    I'll be using bronze bushes here, as the load will be small, the oil lubrication ample.    I'll keep the OD of this bushings as small as possible to keep the friction down.

Hello Dave,

A well reasoned and well thought out solution to the camshaft drive train bearings. I am sure they will give years of trouble free running and one thing less for you to worry about. I doubt you will notice any increase in friction.

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on January 14, 2024, 04:19:37 PM
Some more progress....or maintaining some patience.

Cam timing

I'm going with the same valve timing as the OS FS26 including valve size and lift numbers  ( thanks Peter for compiling that!)

8mm valves
2.35mm intake lift
2 mm exhaust lift

I'm fine tuning the valve, valve cage , lifter bucket, retainer designs but it's looking really good with enough room to do what I want and it's makable.

I'm fairly convinced I need to vent the lifter buckets so they don't get inhibited by pumping issues.   

I have a set of used FS26 valves and valve springs coming as reference  ( found them cheap on the bay).   

Dave

Just an observation. If you reduce the depth of the valve cage counterbore; you will increase the valve guide bearing length significantly.  :thinking:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Mike R on January 14, 2024, 04:36:26 PM
I'm with Mike on this, make the valve cage counterbore only up to roughly where it intersect with the centerline of the intake / exhaust port, and bore the ports with the cages in place.  This will greatly increase the valve guide bearing area and not impact flow.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 14, 2024, 05:58:11 PM
Cam shaft drives

the more I think about this assembly, the more I like bronze bearings in this assembly.   If I have a small ball bearing come apart here, it will FOD out the entire engine with hardened balls in all the gears.   They have no where to go but into the gear train.....

I don't like that at all!    I'll be using bronze bushes here, as the load will be small, the oil lubrication ample.    I'll keep the OD of this bushings as small as possible to keep the friction down.

Hello Dave,

A well reasoned and well thought out solution to the camshaft drive train bearings. I am sure they will give years of trouble free running and one thing less for you to worry about. I doubt you will notice any increase in friction.

Mike

Thank you gentlemen   I agree  and was on the radar  and I'll complete the bore insitu
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: petertha on January 14, 2024, 08:19:59 PM
I'm going with the same valve timing as the OS FS26 including valve size and lift numbers  ( thanks Peter for compiling that!)   

You are most welcome. Glad to see you back in the saddle... for whatever saddle time you may have until 'the commitments' rear up again, LOL.

When I assembled that timing data, for some reason I downloaded all OS brand 4-stroke engines. Partly because there were many to reference & was curious if there was any relationship to displacement or changing over the years. Interpretation gets a bit more speculative at that point. Engines I saw with more outlier timing usually also had some of the more sophisticated aspiration features (YS airbox for example & OS small quotes supercharged engine). Anyways, it dawned on me just recently that I ignored Saito for whatever reason & they should be ~comparable to OS through the years. So I downloaded all those PDFs & will start layering into my spreadsheet. My next project will be spark ignition/gasoline so even less info to go on there. But encouragingly, judging by many successful glow to ignition conversion projects I've seen, the engines seem happy with same methanol timing. Now they say expect slightly less RPM & slightly more heat, so maybe that is fuel or maybe that is unoptimized cam, hard to know.

I wanted to mention this website. I bought some ancillary RC engine for Japanese engines that were either more expensive or harder to source vs the usual N-Am vendors, but could well be part specific. Beware, there are also sneaky cloners on TheBay, some parts are comparable quality, some are not.

https://www.rcjapan.net/
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 14, 2024, 09:39:47 PM
Thanks Peter!   I'll keep that in mind

I wanted the easy start with a simple carb that the fs26 displayed in the article, it's about the same bore and stroke so it seemed reasonable.

the used parts are for reference regarding valve springs and the valve itself,   Purchasing a design check if you will   As they were used, and cheap, it seemed a reasonable approach...

Looking forward to your update on the Satio!    It'll be an interesting read.   Im pretty versed in steam events and effects but I'm still learning about IC stuff

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on January 15, 2024, 09:09:05 AM
That looks great Dave.
Are you intending on routing oil under pressure up through the central drive housing to lubricate the cams and bucket lifters, or by some other external means?
Regards
John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 15, 2024, 01:06:19 PM
That looks great Dave.
Are you intending on routing oil under pressure up through the central drive housing to lubricate the cams and bucket lifters, or by some other external means?
Regards
John

I intend to vent the crankcase at the valve covers ( 8 places) .   That will bring oil mist up to the top of the engine.   Commercial Model 4 stroke engines of this size rely solely on oil blow by from the mixed fuel to lubricate everything in the bottom end including the crankpins, wrist pins and cylinder walls.   Now considering Im spray lubing the bottom end bearings/conrods, the spinning rotating assembly will create a lot of oil mist.   With the inevitable cylinder blow-by,   the oil mist will be transported to the vents where ever I put them.  Based on that the gears and cams will be well lubricated provided I place the vents appropriately at the ends of the engine valve covers.   So that's the plan.
I would say the short answer to your question is yes,   but not the way you may think. :cheers:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on January 16, 2024, 10:48:59 AM
Thanks for the very detailed explanation Dave, and that's not a means of oil movement I had considered. Clever indeed!
Your modelling and workmanship makes each installment of this thread a great read.
Can't wait to see it running.
Regards
John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on January 21, 2024, 02:12:41 PM
Great progress on the valve gear design  :praise2:  +1 for increasing the valve guide length in the cages.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 21, 2024, 02:16:22 PM
Great progress on the valve gear design  :praise2:  +1 for increasing the valve guide length in the cages.

Thanks Roger, all over it.

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on January 21, 2024, 10:07:37 PM
I got the OS 26 valves and valve springs, and I took a few minutes to try to back calculate the spring specifications

I took the following dimensions:

10mm high
6.55mm OD
0.78 mm wire

The first picture is of the ebay listing
I then ran that through a online calculator and got the second photo
I also spent some time reading an article by David Bowes on the subject of model engine valve springs.   It gives some minimum guidelines for engines in different rpm ranges.    When you back in the FS26 valve size and rpm range, it seems to agree with the calculated parameters of the spring.   What I don't know is the as installed valve closed deflection and load, but again, based on the article, it seems to agree.  Im jigging up a spring load vs deflection rig currently so I can confirm the numbers of the actual spring....but the article suggests something like the following.
10000 rpm operation.

Closed valve spring load of the valve    2 to 3 pounds
full open valve spring load               5 to 6 pounds
0.300" OD valve  or just under 8mm

Pretty sporty!!!

I did count on hardening the valve buckets and cams, and the numbers seem to support that.

I will look at a couple of other designs and compare...

Dave

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2024, 01:16:05 AM
Interesting day today     I picked up a book  "Hi Performance Cams and Valvetrains" by Billy Godbold. of Comp cams
Based on the book and some noodling Ive learned a thing or two about the cam profile

2 cam profiles that I've investigated so far   Both are intake cams with the same opening and closing events, but different profiles, and I like the second one much better.

The first one is from a known design and it has a profile approximately like this 

More area under the curve by having a quicker opening, and a bit more gradual deceleration at the peak on the second profile if you look at the two lift profiles.   Max acceleration in the 140g's range so about a 2 pound spring minimum    So the spring size I chose at about 3 pounds at full lift is probably not bad considering I don't really know where the top end is and the acceleration goes as the square of the rpm


Moving along


Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on February 04, 2024, 04:43:12 AM
Interesting profiles Dave....another point for consideration is that the lift velocity (mm/deg) determines how far the lobe's line of contact with the bucket follower is from its center. Stray too wide (too high a velocity) and scoring of the cam on the edge of the follower is a real possibility.
Regards
John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2024, 07:27:16 AM
Interesting profiles Dave....another point for consideration is that the lift velocity (mm/deg) determines how far the lobe's line of contact with the bucket follower is from its center. Stray too wide (too high a velocity) and scoring of the cam on the edge of the follower is a real possibility.
Regards
John

Yes it does John!    It appears to be good in that respect, Though I'm using most of it.   And in actuality, it might be an opportunity to reduce the bucket diameter a touch, if for no other reason than to take some weight out of the valve train, but at this point it appears to be all good dynamically.    The challenge might be to harden these buckets without distortion.   The wall is getting a bit thin, and I may need to fixture these during heat treatment.     I think making one and trying it might be the quickest way forward....then I'll know.

   
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Roger B on February 04, 2024, 08:22:56 AM
Those are some nice profiles  :ThumbsUp:  :ThumbsUp: Are they designed using your standard CAD package or do you have some add ins?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2024, 08:52:56 AM
Those are some nice profiles  :ThumbsUp:  :ThumbsUp: Are they designed using your standard CAD package or do you have some add ins?

Hey Roger, nope.  fusion 360, and excel.....took a bit to sort a clean way through doing an analysis that didn't take hours.

The spreadsheet took a bit, but now I have it and it makes some sense.   It's wild that .002" ( 50 micron) does to acceleration and Jerk
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on February 04, 2024, 09:33:42 AM
Dave

Glad to hear you're on top of the velocity vs diameter constraint.

I know you're not going for a 906 cam profile with huge duration and lift, but for what its worth, and if you're considering a reduction in the diameter of the bucket followers, per Kent Cams the prototype bucket followers were 32.97mm OD x 20.3mm L x 3mm stem (center) length.

John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2024, 11:30:37 AM
Dave

Glad to hear you're on top of the velocity vs diameter constraint.

I know you're not going for a 906 cam profile with huge duration and lift, but for what its worth, and if you're considering a reduction in the diameter of the bucket followers, per Kent Cams the prototype bucket followers were 32.97mm OD x 20.3mm L x 3mm stem (center) length.

John

Hi again John,
Thanks for the feedback on a ACTUAL cam follower!  So to scale that would be about 8.24 mm OD  x 5.1 mm ID x 0.75mm wall thickness.   

There are days I wish I fell in love with a BB Chevy, I could go to the junk yard and pick up one for $100 and park it in the shop and have a prototype right in front of me for ACTUAL dimensions.      Alas, the heart is fickle!      Gathering "Actual" data for this engine is an act of scanning the internet for pictures of "the thing" and then doing the reverse engineering to come up with what I THINK it is ,   and what I think will work with the model in front of me.   Even coffee table books on this car are outrageously expensive from a hobby perspective.

 https://www.amazon.com/Porsche-917-Archives-Catalogue-English/dp/3768838374?asc_source=01HFY6QA7Q8N1TT2Z879WGSZ46&tag=snx79-20

Even then,   it is extremely unclear to me that there is everything in it I need and at $400 to $800 for the book.....well  I can't justify it.

Now Cherry Hill would be disappointed with me, I'm sure.    I've found whatever I can online, and I have a source or 2 that I'll say are "anonymous"   that are close to the subject who have given me some juicy pictures of actual parts, but it's still a bring the part photograph into Fusion and compare it to the known drawings that I do have that I've found on the web, specifically the first picture below.  I take the bore and stroke as a dimensional standard and scale the picture from there.    It's a challenge, and admittedly a compromise.    Well   Life is full of those, and this is a hobby.     The goal is a running engine model.   I wont be driving this at Long Beach, or down the Mulsanne.

I do have a actual cam card for this monster which I'm told Porsche considered rather  "Agricultural" and as my good friend and modeler Steve Huck exclaimed when he looked at it    "Holy Mother of GOD!".   LOL :lolb:

In discussion with him and a few very experienced modelers, the thought was at that timing with that overlap, the probability of a model starting would be low, somethings don't scale well, and it was suggested to back off from that to something a bit more conservative that will run.     The choices out there for that were Steve's V8 models,  which are pretty "aggressive"  or a Schillings profile, which is also a bit aggressive, or copying a commercial engine of near the same bore and stroke with known good power.      I chose the OS FS26 4stroke as it's nearly identical on the bore stroke and valve size.

Valve size.     Another extreme for Porsche!    the Intake valve is enormous!    And it should be!    But at 1/4 scale I have been cautioned that I should not go that big as getting carburation to work at this scale, it's better to have some velocity through the ports to prevent the fuel from coalescing into droplets.  In the model, the valves are both 8mm diameter.    I did match the valve cant angles which are 30 and 35 degrees as I was able to measure from the drawing below.    You can see that asymmetry in the engine on the efxternals,    the OS Fs26 uses 8mm valves as well, so seemed reasonable.

Cam buckets!   Well  I can hear Cheery sighing now...   mine are currently 11mm in diameter  ( 11.11mm OD or .4375") x 9.5mm ID or 0.375" and out of 0-1 tool steel,   Mine are bigger, but I like the size, and I don't think it's outwardly compromising the visual of the model, so I'll leave it as it is.   that works out to the OD of the cam bucket bushing in the section view below which is relieved for the cam lobe per our previous discussion.  I'm not running bushings here, as I'm running the bucket in the cam box directly.  I can add a bushing later if I find it wearing, there's room, but it' currently doesn't mess with my cam options, and as I won't have a direct pressure feed up to the cams I like the extra bearing area here.   the buckets and cams will be hardened 0-1 tool steel.

Unfortunately this model will by necessity be a Engineer as you go proposition     I would Love to have a stack of actual prints and just divide everything by 4 to get my 1/4 scale parts!    that is not the case though. 

The second photo below is a section view of the cad with a known section view drawing from picture 1 superimposed for scaling.   this is how the project has gotten to here so far.    Eating the elephant one bite at a time.
.....lets not even mention the ball bearing crank.    It would be nearly impossible to make a prototype crank at 1/4 scale without a gear shaper.    It's about the only way to do it, and the cutter would have to be specially made up to do so.    the crank webs come very close.  Too close for a milling cutter,  I would admit that with a very small end mill and 4 axis cnc it might be possible....I don't have an active 4th axis in my shop though....

Dave
 






Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2024, 12:57:10 PM
And John,   I love your Avitar.....Fig 13.    8)
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 04, 2024, 12:58:55 PM
Hello Dave,

Be careful not to overthink the cam profiles and valve sizes. You are not actually trying to build a racing engine, rather a scale model, which you hope to run one day. As you already know, I am a firm believer that a model engine should have very conservative valve timing and small diameter valves, in order to give a well mannered, easy starting, engine. A model engine will never deliver it's full power unless it is connected to some form of a (dynomometer) load. Running on a test stand, with no load, and blipping the throttle is not the same.

Cheers

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2024, 01:00:46 PM
Hello Dave,

Be careful not to overthink the cam profiles and valve sizes. You are not actually trying to build a racing engine, rather a scale model, which you hope to run one day. As you already know, I am a firm believer that a model engine should have very conservative valve timing and small diameter valves, in order to give a well mannered, easy starting, engine. A model engine will never deliver it's full power unless it is connected to some form of a (dynomometer) load. Running on a test stand, with no load, and blipping the throttle is not the same.

Cheers

Mike

Couldn't agree more Mike, and thank you so much for all  the help and support, technically and emotionally on this project    I couldn't be here now without your help.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2024, 02:07:24 PM
interestingly enough, the cam profile I like is nearly identical in all respects to the Schilling profile in his book.......Cool  At least I'm converging on something that runs!

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 04, 2024, 02:16:08 PM
That looks like a good choice.

Cool and calm, not hot and wild.

Bit like me really.

Mike   :old:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2024, 02:22:24 PM
That looks like a good choice.

Cool and calm, not hot and wild.

Bit like me really.

Mike   :old:

And it gets  the valve open earlier and closes later.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: petertha on February 04, 2024, 10:41:23 PM
@steamer, can you elaborate a bit. Looking at your Excel chart, I can visualize calculating the area under the curve & comparing cam A&B on that basis. Same for rate of change (acceleration) along the curve which might be meaningful. But can you elaborate on what exactly you are targeting or converging towards? Is it a number or a relative shape that then defines its character? If the subject is too deep & maybe the appropriate answer is 'read the book' that's fine too LOL.

Also, when I did something similar just plotting theoretical valve open & valve closed duration derived off the cam profile, and then applied the typical model engine recommended feeler gage gap between lifter & rocker for example, I was shocked at how many degrees of open duration this trimmed off the theoretical action. I suspect its a function of recommended open gap relative to (low) model engine lift - higher proportion percent compared to FS engine. Would that be another consideration to your chart?

Its looking good!
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 04, 2024, 11:46:56 PM
@steamer, can you elaborate a bit. Looking at your Excel chart, I can visualize calculating the area under the curve & comparing cam A&B on that basis. Same for rate of change (acceleration) along the curve which might be meaningful. But can you elaborate on what exactly you are targeting or converging towards? Is it a number or a relative shape that then defines its character? If the subject is too deep & maybe the appropriate answer is 'read the book' that's fine too LOL.

Also, when I did something similar just plotting theoretical valve open & valve closed duration derived off the cam profile, and then applied the typical model engine recommended feeler gage gap between lifter & rocker for example, I was shocked at how many degrees of open duration this trimmed off the theoretical action. I suspect its a function of recommended open gap relative to (low) model engine lift - higher proportion percent compared to FS engine. Would that be another consideration to your chart?

Its looking good!

Hi Peter, I'll sure try!

What Im targeting is a running engine of course.   That said the first lift plot above showed a fairly leisurely opening for quite some period, with a massive ramp  right when the valve got to maximum lift.  It shows as an inflection in the curve at max lift.  That is very bad dynamically as I'm imparting maximum acceleration right before I want it to rapidly accelerate in the opposite direction!    Jerk, the third derivative position, or the first derivative of acceleration goes to infinity here.....additionally I'm spending a lot of time with the valve partially open, which is not good for our air pump.    in an ideal world the valve would open instantly and minimize the air restriction at the port  ( yeah I know its not possible because the valve would hit the piston, but you know what im getting at)   So seeing this and looking at all three graphs  lift velocity and acceleration you can see that the max acceleraton is right near max lift, which is a point Im trying to control by keeping the follower on the cam here.     So my take away is bad breathing, and bad dynamics because of the location and discontinuity of the acceleration.

Cam 2

I intuitively decided that if I increased the flank radius ( make it more flat and less curved) and increased the nose radius to provide for some deceleration near the peek lift, it would also provide more area under the curve of lift which is valve opening.  More valve opening, better air pump....

the flanks got increase from 0.734" radius to 1" radius and the tip radius went from 1 mm to 2.5mm radius.   

what I see when i looked at the acceleration curve was peak acceleration happens a little bit earlier during the opening and a little later in closing, and the peak accelerations are higher than cam 1, but the curve is at least continuous, so I would think that Jerk would be lower here, and I would be beating up the valve train less.

In  no place I've I even tried to factor in valve lash, it will add non continuous acceleration and infinite Jerk in places I suspect.  Suffice to say I'll be keeping lash at the bare minimum.  I can factor lash in later after I settle on basic geometry

These curves have a derivative interval of about10 degrees, so I suspect there are some corners in the curves that would smooth out with a more refined and smaller interval  ( approaching zero) but I think it's still a useful graph to see what is going on in general.

and Interestingly enough it is very close to the Schilling cam in all respects, though I think the durations are a bit different, the geometry is nearly the same.

Now hopefully I didn't make too many fopa's in this spreadsheet.   As it seems reasonable.    maximum acceleration for cam 1 is 95 G or so at 10000 rpm while cam 2 is about 140 G's  but earlier in the curve and reducing at max lift.

I found as little as 50 microns here or there added to the profile could have a big effect on the dynamics of what's going on.  It was not intuitive at all.
   

Dave

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 05, 2024, 11:51:55 AM
........snip....

In  no place I've I even tried to factor in valve lash, it will add non continuous acceleration and infinite Jerk in places I suspect.  Suffice to say I'll be keeping lash at the bare minimum.  I can factor lash in later after I settle on basic geometry.

.........snip..

Dave

Dave,

Our model engines are so much smaller than a full size engine, therefore the valve/ tappet/ cam clearance (I think you call it lash) effects becomes disproportionately large. A small change in the valve clearance (lash) can have a significant change in the valve event timing. Fortunately, I found there is a simple way to deal with the necessary valve/ cam clearance without effecting the opening, closing and valve lift events.

First you need to decided on your preferred cam profile. Then, reduce the radius of the base (rear side) of the cam by say 10 thou (yellow line) leaving both flanks and tip radius of your chosen cam profile untouched (red line). You can now set the valve / cam clearance to 10 thou which will ensure complete valve closure and sealing. The valve opening and closing points and maximum lift remain unchanged but you do have the necessary valve clearance (lash) to ensure complete valve closure and sealing.

(https://lister-engine.com/coppermine/albums/userpics/10013/normal_CAM2~0.jpg)

Look at it another way. Only one third of the cam profile is actually doing work, the remaining two thirds is contributing nothing except perhaps preventing the valve from closing properly. So why not cut it back slightly to ensure the valve closes completely. The valve opening and closing events remain unchanged. Win, Win.

Cheers   :cheers:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 05, 2024, 01:56:44 PM
Thanks Mike       I'll do that!

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on February 05, 2024, 02:59:46 PM
Such a simple solution to a vexing problem! Thank you for that, Mike.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Charles Lamont on February 05, 2024, 03:36:12 PM
What Mike says. Mostly. However I would say that for this sort of size of model a valve clearance of 0.010" is more than necessary or desirable.
Firstly, if the valve clearances are not accurately set, then your acceleration curves and such are thrown to the wind. Accurate setting means you do not really need a lot of clearance.
Secondly, a large clearance on the base circle radius makes it difficult to design the ramps between the clearance and the bottom of the flank. At least not if you want a cam that looks as though it has a continuous smooth surface.
As I ground the cams for my Seagull, I decided I could halve ET Westury's recommendation, and went for 2-1/2 thou, and that seems to be working nicely.
I designed them with ramps in the form of a radius connected to the relieved base radius by short tangents, like this exaggerated diagram:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 05, 2024, 10:54:23 PM
I like it Mike!   .010 might be a bit much, and I think I can cut it a little closer, but yeah

I also plan to hone the top of the valve buckets to adjust. 

Dave 
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 05, 2024, 11:11:47 PM
I like it Mike!   .010 might be a bit much, and I think I can cut it a little closer, but yeah

I also plan to hone the top of the valve buckets to adjust. 

Dave

Hello Dave,

The 0.010" was by way of an illustration. Anything less would hardly show on the sketch I attached.

Adjusting the clearance by honing the top of the valve bucket will be a long tedious process. Even with a box full of ready made valve buckets of various thicknesses available, it can still be a long job. Fit all the valves with your first guess, measure the gap, dismantle, fit different valve buckets, re-build, re-measure, repeat, repeat.          Been there several times before.

Cheers

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: RReid on February 06, 2024, 12:45:52 AM
On my DOHC Halfa build, I adjusted the valve clearance mostly by shaving bits off the valve stems, rather than the buckets. I did do the shell game with the buckets initially to get the best starting points.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: AlexS on February 06, 2024, 01:55:39 PM
can't you measure the distance from valve stem to cams and then make accurate shims (buckets)?
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 06, 2024, 06:07:37 PM
can't you measure the distance from valve stem to cams and then make accurate shims (buckets)?

I could with a surface  grinder.   But I don't own one

I can undercut the cam and lap the bucket though.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: jcge on February 06, 2024, 10:26:53 PM
I offered the dimensions of the prototype part only for reference, and as you've found, there's not a lot of true dimensional data about in the public domain. It was certainly not as to lobby for scalar perfection. Apologies if my post implied that. And the approach you outlined to scaling from the available drawings and photos, is spot on in opinion. I often refer to DIN standards (they have standards for EVERYTHING) for minor mechanical elements to imply the size and placements of other features surrounding those simple parts.

I have a copy of the W. Naher book, and I can assure you it does not have the level of dimensional or drawing detail of the engine that is not otherwise available elsewhere.
OEM typ.901 parts have much in common with the typ.912, and supplier catalogues list many more critical dimensions that the above reference.

I think you've taken a very clever approach of using an increased cam follower diameter to effectively include the envelope of the prototypes scalloped (for cam clearance) bushing. It delivers a lot of latitude in base circle diameter, relaxes the velocity constraint and gives more choices in spring and retention arrangements. Not to mention component count reduction!

Really enjoying watching your build come together
Regards
John
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 07, 2024, 12:07:54 AM
Thanks John     I'm trying

It's nice to hear that.   I've taken on many big projects in my life and there are those who support me through it all...and then there are those who couldn't be bothered....and then there's those other folk who have lost the plot on projects like this... it's the journey...not the destination.    They criticize and mock....for no other purpose than to hear themselves talk I think.   Those drain me of my energy sometimes...and then we'll    I tell them to buggah off!  And I make another part ..and I feel better.
I like the first type of people better! :cheers:

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 07, 2024, 12:52:33 AM
On my DOHC Halfa build, I adjusted the valve clearance mostly by shaving bits off the valve stems, rather than the buckets. I did do the shell game with the buckets initially to get the best starting points.

I'm going to start by making the parts as identical as I can....it will be a touchy process as I started with some prototype parts this past weekend.   boring the two parts will be the way forward.  I need to hold the depths of the bores tight on both of these parts.    So I'll need to make up a nice boring bar for this....Also I need to confirm the buckets don't go "Potatoe chip" on me when I harden them.    Well  At least no too much

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 07, 2024, 12:58:54 AM
I like it Mike!   .010 might be a bit much, and I think I can cut it a little closer, but yeah

I also plan to hone the top of the valve buckets to adjust. 

Dave

Hello Dave,

The 0.010" was by way of an illustration. Anything less would hardly show on the sketch I attached.

Adjusting the clearance by honing the top of the valve bucket will be a long tedious process. Even with a box full of ready made valve buckets of various thicknesses available, it can still be a long job. Fit all the valves with your first guess, measure the gap, dismantle, fit different valve buckets, re-build, re-measure, repeat, repeat.          Been there several times before.

Cheers

Mike

Mike
Your wisdom is always welcome my friend.   I will look into relieving that cam base circle.     I want to get the valves, buckets and cages as accurate as I can make them first, and between the 3 parts  ( Cam, bucket and Stem) get the "lash" as close to constant as I can.  After that I think lapping the buckets will be the plan.   I don't have a lot of room to grind the stems.   But I've left material on the bucket to adjust.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 07, 2024, 01:07:04 AM
What Mike says. Mostly. However I would say that for this sort of size of model a valve clearance of 0.010" is more than necessary or desirable.
Firstly, if the valve clearances are not accurately set, then your acceleration curves and such are thrown to the wind. Accurate setting means you do not really need a lot of clearance.
Secondly, a large clearance on the base circle radius makes it difficult to design the ramps between the clearance and the bottom of the flank. At least not if you want a cam that looks as though it has a continuous smooth surface.
As I ground the cams for my Seagull, I decided I could halve ET Westury's recommendation, and went for 2-1/2 thou, and that seems to be working nicely.
I designed them with ramps in the form of a radius connected to the relieved base radius by short tangents, like this exaggerated diagram:

Yup   Similar approach to what Mike is talking about,       And from the perspective of lash, the key will still be making all the part as identical as possible....   the better I do there, the less adjustment I'll need to do later.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 07, 2024, 01:09:10 AM
On my DOHC Halfa build, I adjusted the valve clearance mostly by shaving bits off the valve stems, rather than the buckets. I did do the shell game with the buckets initially to get the best starting points.

I'm going to start by making the parts as identical as I can....it will be a touchy process as I started with some prototype parts this past weekend.   boring the two parts will be the way forward.  I need to hold the depths of the bores tight on both of these parts.    So I'll need to make up a nice boring bar for this....Also I need to confirm the buckets don't go "Potatoe chip" on me when I harden them.    Well  At least no too much

Dave
What would cause parts to warp in hardening? Is it evenness of heating, or something in the quench itself?


I didn't  get all the subtleties in  the cam discussion,  but still wowed by the model!

 :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 07, 2024, 01:12:40 AM
On my DOHC Halfa build, I adjusted the valve clearance mostly by shaving bits off the valve stems, rather than the buckets. I did do the shell game with the buckets initially to get the best starting points.

I'm going to start by making the parts as identical as I can....it will be a touchy process as I started with some prototype parts this past weekend.   boring the two parts will be the way forward.  I need to hold the depths of the bores tight on both of these parts.    So I'll need to make up a nice boring bar for this....Also I need to confirm the buckets don't go "Potatoe chip" on me when I harden them.    Well  At least no too much

Dave
What would cause parts to warp in hardening? Is it evenness of heating, or something in the quench itself?


I didn't  get all the subtleties in  the cam discussion,  but still wowed by the model!

 :popcorn: :popcorn:



Heating up thin walled parts to cherry red and quenching in oil....If I can fixture it so I can quench it symmetrically,  I might stand a chance.     It all takes some thought.....but who am I to tell Crueby about planning ahead!    :praise2:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: crueby on February 07, 2024, 04:52:39 AM
On my DOHC Halfa build, I adjusted the valve clearance mostly by shaving bits off the valve stems, rather than the buckets. I did do the shell game with the buckets initially to get the best starting points.

I'm going to start by making the parts as identical as I can....it will be a touchy process as I started with some prototype parts this past weekend.   boring the two parts will be the way forward.  I need to hold the depths of the bores tight on both of these parts.    So I'll need to make up a nice boring bar for this....Also I need to confirm the buckets don't go "Potatoe chip" on me when I harden them.    Well  At least no too much

Dave
What would cause parts to warp in hardening? Is it evenness of heating, or something in the quench itself?


I didn't  get all the subtleties in  the cam discussion,  but still wowed by the model!

 :popcorn: :popcorn:



Heating up thin walled parts to cherry red and quenching in oil....If I can fixture it so I can quench it symmetrically,  I might stand a chance.     It all takes some thought.....but who am I to tell Crueby about planning ahead!    :praise2:
Yeah, well, I DO tend to do a lot of thinking and planning ahead, making notes, sketches, later on tearing them up and drawing more while imagining I can hear the machining gods laughing so hard they fall off their shop stools...   :Jester:   Many times it all comes down to, "Doh - Put a rivet over there to hold it!"

Doing some tests on a process before assembly line making dozens of complex parts its WELL worth it!
 :popcorn: :popcorn:
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Charles Lamont on February 07, 2024, 09:50:45 AM

What would cause parts to warp in hardening? Is it evenness of heating, or something in the quench itself?


Another likely cause is the shape of the part. As hardening causes changes to the crystalline structure of the metal, it can also cause dimensional changes. Silver steel (drill rod to you) usually grows a bit. A bucket tappet is likely to end up tapered because the base disc and cylindrical walls behave differently. There is also likely to be some inconsistency in the quench, in getting liquid down the hole. I think this is what causes ovality. I had a right game with the Seagull tappets (http://www.charleslamont.me.uk/Seagull/tappets.html (http://www.charleslamont.me.uk/Seagull/tappets.html)), with eleven attempts needed to make four. On 9/32" diameter, after hardening (in water) they were typically at least 0.001" out in combined taper and ovality. Lapping them true and to size was not as difficult as I feared.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 24, 2024, 05:38:25 PM
Today's effort.   Fixture build time.

A 4th axis trunnion fixture for the cam box on one side and the cylinder heads on the other, specifically the features for the valves and valve buckets.   

Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 24, 2024, 05:49:47 PM
Impressive fixture. Does your CAM sort out the trunion offsets?

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 24, 2024, 05:53:45 PM
Impressive fixture. Does your CAM sort out the trunion offsets?

Mike

Hi Mike,
No  I worked that out.   1.096 offset on one side and 0.210 on the other for the cam box and cylinder head respectively.    I'm making up the trunnions   Obviously, there is one on the other side...though it's not shown.    I'll have a plate with a bearing to support the far end..

I'll do the center sections in the vise, and the fins in a seperate fixture to get 5 sides on the cylinder head..    The trunnion is just for the inclined surfaces for the valves, cam tunnels ect.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 24, 2024, 06:07:53 PM
Mike

Also, the cam box is biased slightly to one side as the angle for the valve features is 30 degrees on one side and 35 degrees on the other.    Where these two features cross needs to be at the center of the trunnion.  then it's easy to pick up and machine.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 24, 2024, 06:15:07 PM

   The trunnion is just for the inclined surfaces for the valves, cam tunnels ect.

Dave

Ah! now I understand.  The trunnion is being used as a very accurate rotary table controlled angle plate. So each separate face can be treated as normal 2.5 D geometry with a little mandraulic input for the lateral offsets. That's still tricky work but should make for good repeatability for machining the valves etc.
I thought for a moment you had won the lottery and now into 4/5 axis machining.
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: Vixen on February 24, 2024, 06:42:36 PM
Hello Dave,

Here is a 'happy camper' at Crossthwaite and Gardner With a full size W125 cylinder head/ block set up on a big 4th axis trunnion to do the same work as you are planning for the 917.

(https://lister-engine.com/coppermine/albums/userpics/10013/26992622_1790915167619618_6614880533750153999_n.jpg)

Things would be a lot easier if we both had a 'walk in', ' sit on' Haas milling machine to play with.

Cheers    :cheers:

Mike
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 24, 2024, 07:03:58 PM
Yup!   Exactly   nice bit of kit though mine will be manual.

Dave
Title: Re: 1/4 scale Porsche 917 180 degree V12 Build
Post by: steamer on February 25, 2024, 02:50:40 AM
Made a lot of chips!    buried Samantha Bell....I'll get them cleaned up and drill and tap some holes tomorrow.

The dividing head needs to go to the bed, so I'll probably need to machine the base of the DH so the key matches the Tormach T slot.

Dave
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