Model Engine Maker

Engines => Your Own Design => Topic started by: steamer on July 06, 2016, 12:40:00 AM

Title: 917 180 degree V 12
Post by: steamer on July 06, 2016, 12:40:00 AM
I'll just leave this right here.......




NOTE   LINK TO BUILD THREAD

https://www.modelenginemaker.com/index.php?topic=10504.msg240595#msg240595
Title: Re: Momentary lapses of reason......
Post by: crueby on July 06, 2016, 12:47:01 AM
Wonder if Jo has castings for one of these...   :Lol:
Title: Re: Momentary lapses of reason......
Post by: bruedney on July 06, 2016, 12:58:32 AM
This may help with assembly
(http://i144.photobucket.com/albums/r182/hazze959/Bil%20Bilder/Porsche%20917/917-enginespraumlngskiss_zps1ecf92a8.jpg)

Bruce
Title: Re: Momentary lapses of reason......
Post by: bruedney on July 06, 2016, 01:00:02 AM
Or this
https://www.youtube.com/watch?v=j3CkVwtOPX4
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 01:01:36 AM
 ;D 8)

come on Jo...you must have a casting set for one of these?   hmmmm    Like 1" bore x 3/4" stroke?
Title: Re: Momentary lapses of reason......
Post by: b.lindsey on July 06, 2016, 01:05:20 AM
A perfect project for the monitor guys once they finish their builds 😉

Bill
Title: Re: Momentary lapses of reason......
Post by: bruedney on July 06, 2016, 01:08:17 AM
I'll let Chris start since he is already finished

Bruce
Title: Re: Momentary lapses of reason......
Post by: crueby on July 06, 2016, 01:51:19 AM
I'll let Chris start since he is already finished

Bruce

Ummm... gulp... ummm... oh yeah! I am still working on the Corliss twin! Yeah, thats it!

Whew...


There are some here that could make one. Like the guy working on the merlin, just for one example. I might be able to make a nice display stand for this!
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 11:48:31 AM
Here is a longitudinal cross section to add to the collection.
The individual components are not that complex in themselves. There are just a lot of them with twelve cylinders.

(http://i901.photobucket.com/albums/ac218/v8vixen1/917_11295125422.jpg)
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 01:11:16 PM
Hey Vixen,

The split case concerned me for a bit, but I think I could get it done.    The cam gear drives and induction would have me nervous though!    Not much room for a valve cage on those heads....might have to move them slightly...or run with the valve seat in the head.
Crankshaft is ROBUST....interestingly   The output shaft geared off the center of the crank is only 24mm of titanium!....


Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 03:05:08 PM
Hi Dave
The center drive is a neat way of overcoming the potential problems of long whippy cam shafts and crankshaft.
The show stopper is probably the twelve individual inlet stacks, trying to balance twelve individual carbs could be almost impossible as would a making a miniature 12 outlet mechanical fuel injection pump.
May have to settle for a Stuart Turner

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 03:11:14 PM
Once the Wallaby is done.....I'll have some band width ....hopefully...

The center drive isn't the problem....Getting the stack height of all the cylinders and the gear mesh right..would be a challenge!!!! and  .as you say the induction would be tough to do.....One could go the Turbo version of this, and put the Propane feed in a fake turbo housing......

Need to talk to Keith about his fuel injection system.....

Dave
Title: Re: Momentary lapses of reason......
Post by: Jasonb on July 06, 2016, 03:18:35 PM
Jo if you want to make one these are the castings you need :LittleDevil:

(http://img.photobucket.com/albums/v156/jasonballamy/Engineering/Lightweight/DSC00944_zpsh7a5k9wx.jpg)
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 03:19:57 PM
Jo if you want to make one these are the castings you need :LittleDevil:

(http://img.photobucket.com/albums/v156/jasonballamy/Engineering/Lightweight/DSC00944_zpsh7a5k9wx.jpg)

Hell she'd be half way there!!!!
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 03:21:52 PM
Building  a turbo Can Am version would be the smart way round the induction problem. No need for a working turbo on a scale model. Then a single fuel injector a la Keith, would be a good way to go.

When you finish the Wallaby, I can give you some plenty of well documented photos of a 917 strip and rebuild.

Mike
Title: Re: Momentary lapses of reason......
Post by: Jasonb on July 06, 2016, 03:22:18 PM

Hell she'd be half way there!!!!

Thats about as far as she goes with her engines :mischief:
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 03:25:30 PM
Building  a turbo Can Am version would be the smart way round the induction problem. No need for a working turbo on a scale model. Then a single fuel injector a la Keith, would be a good way to go.

When you finish the Wallaby, I can give you some plenty of well documented photos of a 917 strip and rebuild.

Mike

Propane might be a good way to get around the length of the induction header as well....I think fuel would coalesce in a long tube like that


Oh you tease me so!!!!

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 03:26:05 PM
Heads down----- IN COMING
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 03:26:59 PM

Hell she'd be half way there!!!!

Thats about as far as she goes with her engines :mischief:

Oh Jason.....I can't go there!!!!!! :-\ :censored:   She's gotten further than I!   but I see my retirement from all the racing coming soon....maybe more time in the shop.   
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 03:33:23 PM
Heads down----- IN COMING

Oh Crap!.....
Title: Re: Momentary lapses of reason......
Post by: Tennessee Whiskey on July 06, 2016, 03:47:34 PM
Racing retirement , he must have found the female gender :facepalm: :lolb:

Cletus
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 03:50:39 PM
Not William!    ME!!!!

He'll get his license soon enough.....by then he'll be self sufficient with the rigs and the set up......time for ME to retire.

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 05:04:47 PM
At 1" bore, a pretty big engine.....you are just smaller than 1/3 scale

Stroke works out to about .75"....near enough.....depending on what vintage engine you were modeling

Rod  journals would be .5625 and crank journals 0.75"

Robust!

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 05:15:53 PM
Just under 1/3 scale.... Nice size

You know it makes sense. Go for it

Mike
Title: Re: Momentary lapses of reason......
Post by: Tennessee Whiskey on July 06, 2016, 05:22:19 PM
Ok then, he'll be driving HER to the races and not old Dad. SHE better learn to wrench :lolb:

Cletus
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 05:33:36 PM
Just under 1/3 scale.... Nice size

You know it makes sense. Go for it

Mike

Oh I have work to do first!    Wallaby running, then a bunch of research, engineering and drawing.     I may toggle you for those photo's Mike...Might want to make a single cylinder mule to prove the parts out......my mind is racing!


Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 05:41:09 PM

Might want to make a single cylinder mule to prove the parts out......my mind is racing!


Dave,
Maybe I should stop encouraging you. Sounds like you have got it bad.
A single cylinder test piece would not be a mule, it would be a thoroughbred.

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 06:10:03 PM
Hey that's why I got into this in the first place!   encourage all you want!

The kids have been a distraction......but they are a distraction for such a short time...

Keep it coming!!!!

Dave


This started from a dream and stubbornness!..was designed, engineered, lofted and then built once I built the building I built it in.  The engine was designed, patterns made, had it cast and I then machined....along with the Boiler and it's design and fabrication.......
(http://i164.photobucket.com/albums/u27/mcandrew1894/Steam%20Launch%20Rushforth/P9150039.jpg) (http://s164.photobucket.com/user/mcandrew1894/media/Steam%20Launch%20Rushforth/P9150039.jpg.html)

 8)  I can't say that was momentary......it took 13 years......but I had twins in the middle of it!......

(http://i164.photobucket.com/albums/u27/mcandrew1894/Steam%20Launch%20Rushforth/Hibiscus018.jpg) (http://s164.photobucket.com/user/mcandrew1894/media/Steam%20Launch%20Rushforth/Hibiscus018.jpg.html)
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 06:28:48 PM
You can say that this hobby is expensive in time and money.....and I'll agree with you!

But no one will ever convince me it's not worth every penny!

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 06:42:50 PM
Some folk chose to put up a signpost with a fancy house name. I put a simple sign on my workshop door. It says "The Answer"

Mike
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 07:19:49 PM
Dave,
Porsche were never as secretive as Mercedes Benz, so you will be able to find plenty of photos and information on Google. Porsche sold many 917's into private hands so their technology has be spread around. There are photos of a number of detailed rebuilds to be found. Porsche themselves have an exploded display engine in their Stuttgart museum.

Unfortunately, I think the two cross drawings you now have are all that is readily available on the web. They should be enough, when used together with the photos of piece parts, to get close enough for a scale model. You could try the guy who did that 3D animation, he may be willing to help you. Who knows?

The 917 was on my short list of possible engines before I commenced building the MB W165. I stalled at the problem of fueling the 12 separate inlet trumpets. The idea of the Can-Am version of the engine with dummy turbos and Keith's idea of a single point fuel injection using a Megasquirt ECU (who thinks up these names?) never occurred to me. I am sure that is the answer.

I now see the reason for your tag "Steamer".  That's a good looking boat and the steam plant looks excellent. I looked at your location on the map. What a coincidence, I was born in a town called Leominster near to Worcester in the county of Worcestershire in England many, many years ago.

Mike





Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 07:27:15 PM
Well I'll be dipped!      A pair of Leominsterites, who like Lemans, Model Engines, and things mechanical!


Who'd a thunk!

 8)

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 07:29:39 PM
I'm sure tonight I'll have a sketch pad handy and some doodles going on about this engine. .....should be fun!

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 07:38:49 PM
Dave,
Beware, it's a long engine. The scale may be dictated by the travel on your milling machine as much as anything.
The engine was so long that the designers were forced to move the driver so far forward in the car, that his feet were way ahead of the front axle. No safety crumple zone in those days. David Piper lost his leg when he crashed in a 917 during the filming of Steve McQueen's film Le Mans.
Those were the days when sex was safe and motor racing was bloody dangerous. How things change?

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 07:58:23 PM
I've got about a 6 x15 x 12 high work envelope....if it's bigger than that, I'm going to a smaller scale!!!

I read a report on the 917 that at the end of the Mulsanne straight, the aero force on the body was great enough to push the shell down against the drivers toes!...making going for the brakes a challenge!....if you look at the chassis on that thing..it would appear so spindly that it's amazing they could spare that much room in the drivers seat cushion!   :LittleDevil:

The other thing I noticed was that part of the tube frame was a lubricating oil reservoir?    to save weight..

HARD CORE!......

But that's what it took!   

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 08:10:05 PM
You should have no problem with 1/3 scale on that mill bed. It's huge compared to my Austrian made Emco F1.

Apparently they pressurized the oil in the space frame, by a small amount, as a simple way to check the structural integrity of the tubes and welds. Everything did more than one job

We pronounce Leominster as lemster, what's your take on the name

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 08:13:53 PM
yes   but it is manual.   I do have a DRO....but a CNC mill would be a better tool for that job

However, If I dispense with all th external fins on the engine case, it's not that bad....just a lot of work and fixturing.

What are you using for cylinder liners?

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 08:18:47 PM
You should have no problem with 1/3 scale on that mill bed. It's huge compared to my Austrian made Emco F1.

Apparently they pressurized the oil in the space frame, by a small amount, as a simple way to check the structural integrity of the tubes and welds. Everything did more than one job

We pronounce Leominster as lemster, what's your take on the name

Mike

That's funny!    We pronounce it  LEMON-STIR,......though you can bet we get a lot of people asking "Is this LEO Min Stir"?
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 08:32:33 PM
I never got as far as designing the cylinders. The photos show the fins as being an integral part of the cylinder, just like on a Beetle.
I would have thought the cylinders and heads would be very similar to a large air cooled aircraft engine. I used a gang of slitting saws to cut the fins into the steel cylinders of my Bristol Mercury radial engines. Have a look at www.modelengineeringwebsite.com/Bristol_Mercury_VIII.html and keep clicking on the zoom button to see the detail.

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 08:34:45 PM
Will do Mike.....I'll probably go for 1144 Stress Proof.    and make them one piece as well.

Dave
Title: Re: Momentary lapses of reason......
Post by: Jasonb on July 06, 2016, 08:47:14 PM
Could you not just bolt two of these together?

[youtube1]https://www.youtube.com/watch?v=p1wpi2o1Q2o[/youtube1]

And you know that once you have the engine you will have to make the chassis.

J

PS Mike did you enjoy your cycling today ;)
Title: Re: Momentary lapses of reason......
Post by: Jasonb on July 06, 2016, 08:56:18 PM
1/4 scale looks quite nice too

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=13&cad=rja&uact=8&ved=0ahUKEwiQmbDPzt_NAhWrKcAKHdk_BIsQFghdMAw&url=http%3A%2F%2Fwww.autoevolution.com%2Fnews%2Fyou-need-this-14-scale-porsche-type-917-engine-that-is-being-auctioned-102728.html&usg=AFQjCNE1-whLxtey-zHGhOLSuAlojbNMPQ&sig2=CoUZkAPamBMKStnzUitNSg
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 09:05:15 PM
YUP  Saw that Jason.

Too small!....

It's already small at 1/3   1" bore will be easier to get running I think...

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 06, 2016, 09:10:35 PM
Well that's effectively what Porsche did when they built the 4.5 litre flat 12 cylinder engine for the 917. Many components were identical.

"once you have the engine you will have to make the chassis" Well if you start with an all enveloping body shell you may not need to do the engine at all.

Today's stage of the Tour de France was as they say "magnifique" Every stage is so different. The main title contenders were quite content to sit in the peloton group and let  Van Avermaet charge ahead all day long, as he was considered to be a 'one day wonder' and not a general classification threat.
Title: Re: Momentary lapses of reason......
Post by: steamer on July 06, 2016, 09:17:19 PM
122cc.....That'll hurt you!..

Title: Re: Momentary lapses of reason......
Post by: Art K on July 07, 2016, 12:40:16 AM
That 917 engine would be quite the thing to scale, I think I'll stick with something a little more domestic. I am missing :'( the tour this year, we gave up cable. No sitting in front of the TV watching the French countryside go by for me this year. What race engine was it that got its start as a fire pump engine? It had to be light enough to be carried into place. I have the book at home and I'd look it up but I'm on vacation. Picked up a cool book at the NAMES show a few years ago.
Art
Title: Re: Momentary lapses of reason......
Post by: Roger B on July 07, 2016, 07:23:03 AM
I think that you mean the Coventry Climax  :headscratch:
Title: Re: Momentary lapses of reason......
Post by: steamer on July 07, 2016, 05:21:11 PM
I just noticed what appears to be scavenging oil pumps in the bottom cam shaft galleries.   This would make sense to me   Was wondering how they got the oil out of that part of the engine.

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 07, 2016, 07:05:20 PM
Dave,
Well spotted. The two shorter pumps are the scavenge pumps, one drains the front of the dry sump and the other drains the rear. The longer pump is the pressure pump which supplies the lubes to the crankshaft bearings camshaft bearings etc. Note, that the combined length (volume) of the two scavenge pumps is always larger then the pressure pump, usually about 1.5 times larger. This is because the scavenge pumps pick up more air, froth and used oil than the volume of oil delivered by the pressure pump.

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 07, 2016, 07:22:52 PM
Yes Mike, those are quite clearly visible, and your explanation as to which ones do which is spot on!.    However, those aren't the ones of which I speak.

Warning!    largish picture file attached.

In the cut away on the front side and back side of the cam shaft boxes, at the bottom.   if you enlarge that picture you will see a pair of small gear pumps driven off the ends of the lower cam shaft.  My only explanation for these is they must be auxiliary scavenge pumps to move the oil from the bottom of the cam boxes back to the sump.

Is this the correct explanation?     is the question.

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 07, 2016, 07:27:44 PM
I did some research online today regarding this.  the illustration is correct, there is definitely something there, and it appears to be a oil pump.   and considering the fact that all the other pressure lines are internal to the engine, I am assuming it is a low pressure return line.

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 07, 2016, 07:37:44 PM
Dave,

Ah, those little pumps.
You are quite correct, there are four small scavenge pumps driven off the ends of the camshafts. As you surmise, their purpose is to drain the surplus oil from the ends of the cam boxes. Multiple scavenge pumps to drain specific points is not uncommon, The MB W165 has 7 scavenge pumps and three pressure pumps.

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 07, 2016, 07:41:43 PM
Thanks Mike!   I'm still trying to trace the pressure side of the engine...It would appear there is an oil "rail" machined into the case that runs front to back on the engine, and that there are cross drilled holes to the mains.    I haven't figured out the feed to the cam boxes yet though.  External pressure lines from the case?.

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 07, 2016, 08:14:38 PM
Dave,

The oil galleries are not too clear on the cross section drawing. However, you can see the cast in external oil galleries more clearly on the photos below. The main scavenge pumps, pressure pumps and pickup strainers are sandwiched between the two halves of the crankcase and connect to the external cast in oil galleries on either side of the crankcase. The galleries also connect to some sort of manifold box on the front of the engine. The oil return pipes from the cam box scavenge pumps are routed into this box. I am not sure exactly how the pressure oil reaches the cam boxes, probably by external pipes or perhaps through the central cam drive casing. The big bore pipes to and from the oil tank and cooler also connect to the manifold box on the front of the engine.

Hope this helps

Mike


(http://i901.photobucket.com/albums/ac218/v8vixen1/21844550.Casewithdist.shaftdriveshaftandfandriveinstalled_2.jpg)

(http://i901.photobucket.com/albums/ac218/v8vixen1/21844503.BareEnginecasewithstudsinstalled.jpg)

(http://i901.photobucket.com/albums/ac218/v8vixen1/21844891.Casehalfstogethertocheckallthegearlashes.jpg)

(http://i901.photobucket.com/albums/ac218/v8vixen1/21933262.MVC034S.jpg)
Title: Re: Momentary lapses of reason......
Post by: steamer on July 07, 2016, 08:30:02 PM
Hey Mike,

Found it...it's up through the cam gear case I think

http://hellafunctional.com/?p=386

5th photo down....you see the 4 studs that hold the gear case to the crank case, in the upper left position of that flange, you can see the oil hole leading to the oil gallery...

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 07, 2016, 08:47:48 PM
Dave,

I am sure you are correct about the oil port in the gear case. A ported oilway is a far better engineered solution than external pipes.
That hellafunctional website is one of the best to show the internal details of the engine. You can now sit there for hours searching out the details. Did you notice the serial number for the crankshaft? It starts 912..... so is the genuine article and not a repro.

Mike
Title: Re: Momentary lapses of reason......
Post by: Admiral_dk on July 07, 2016, 09:33:43 PM
I'm sorry to but in here, but I think that the hole you spotted just oils the gear train for the cams - not enough area to oil all camshaft bearings there. Look at the bigger holes from the gallery over each cylinder in the same picture - I suspect that they are the suppliers through external "hoses".

I will agree with Vixen that it would be better if they where "internal" - on most bikes I have worked on they are big holes around two (or more) studs in the cylinder block, holding the head - but perhaps Porche where worried about that would be heating the oil too much. I've only once worked on a VW Beetle engine in my teens and the details eludes me now  :old: - in case you wonder - all old Porche engines fit in the Beetle and vice versa (on the others gearbox), they are that similar.
Title: Re: Momentary lapses of reason......
Post by: Art K on July 08, 2016, 01:31:40 AM
Roger,
Thanks, that's the ticket. Coventry Climax. I think that building one of those would be momentary lapse of reason enough for me, except it wouldn't really be a momentary thing at all.
Art
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 10:14:33 AM
Dave,
Other than the bore and stroke, do you have any other dimensions for the engine? How do you intend to scale the drawings?

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 07:10:28 PM
Mike,

Blow up the section drawing twice model size to scale dimension for the start.   Working from the crank out, redraw to correct scale, and perform the required engineering to make the parts work.   That will drive the external dimensions and features, along with photo's ect.  Finishing with external geometry and features.   Enough to make it look right anyway.
 

Currently looking at 1" bore x .75 stroke with .562 crank pins and about 122cc   Bit of a beast, but it makes for part sizes that are easier to deal with.

Now if you happen to have a friend with a full set of working drawings of the original, well that might help.....and I'll make sure I play the lottery tonight too!.

What had me thinking this morning was to have the case and cam tray 3D printed in aluminum, with the hole features undersize, and then treating the parts as castings and finishing to size..... I have quite a bit of experience now in that arena...

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 07:23:41 PM
Dave,
OK, so you are going for the bore and stroke dimensions you prefer rather than an exact 1/3 scale.
What CAD package do you use? With AutoCAD there is a neat way to import a bit map image, stretch the image to the required size, you can then trace/ draw over the image to produce accurate CAD drawings to your chosen size. Saves a lot of ruler and divider work.

Tell me more about 3D printing in aluminium.

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 07:32:47 PM
Exact 1/3 size is 1.13 bore x 0.93

At 29.4% we get 1" x 0.823"

0.823 is a pretty odd ball dimension....even in Infernal....and the strokes varied a bit from engine to engine.

Don't mind cutting gears or making gear cutters.....not that hard, so what ever the spacing comes out to, we can do it.

One supplier of DMLS parts...just give them a 3D cad model.    Bulk tolerance is about +/-.005"....and about 80% billet strength.....Prices would be comparable with custom castings......

https://www.protolabs.com/documents/united-states/alsi10mg.pdf

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 07:38:33 PM
Dave,
OK, so you are going for the bore and stroke dimensions you prefer rather than an exact 1/3 scale.
What CAD package do you use? With AutoCAD there is a neat way to import a bit map image, stretch the image to the required size, you can then trace/ draw over the image to produce accurate CAD drawings to your chosen size. Saves a lot of ruler and divider work.

Tell me more about 3D printing in aluminium.

Mike

Besides, If I go down the EXACT size route...then if we're going to have some intellectual integrity, I should work from original parts or original drawings and not reverse engineering it from two section drawings that may or may not be accurate.....

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 07:57:25 PM
For instance, that cross over duct on your supercharger could have been 3D printed hollow and then post machined.   The downside would be the alloy might have a different color than the rest of the supercharger....
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 08:21:11 PM
Solidworks
Title: Re: Momentary lapses of reason......
Post by: Jasonb on July 08, 2016, 08:24:33 PM
1/3rd scale does work out quite close to 1 1/8" x 15/16"

But 3/10 is not a bad ratio either, if its good enough for John Deere models its good enough for this ;)
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 08:30:17 PM
If I go the 3D printed "casting" route, the part has to stay under 10.5" long, and at 3/10 scale that works....

Additionally, I'd like to keep with standard sizes if possible as It minimizes how many custom reamers and such I need to make.

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 08:33:03 PM
I think that gear pump would be the scariest part of the job for the most part....guess I'd start with that      That and the crankshaft.

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 08:35:27 PM
I suppose I could go to 1" x 0.8125 and have better "Fidelity"....

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 08:41:57 PM
A six throw crankshaft, some ten inches long with a precision cut output gear in middle, looks pretty scary to me. If you can achieve that then everything else would be plain sailing.
Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 08:47:29 PM
Yeah it does look scary doesn't it Mike!     I wonder about a lap joint in the center half round-half round held together with the gear.     Would need some layout to figure that out....and some damn tight tolerances to make work...but can't be as bad as a scale Hirth joint!

Dave

Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 08:56:04 PM
you could also put two ball bearings there ....perhaps.....on the crank

The alternative would be to lay out the crank and see if a say 3/4" OD cutter could make it in there....you would need a roughing cutter and finish cutter.

This is a good dialog....work out the problems, or at least shine some light on them!...



Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 09:00:01 PM
A Hirth coupling may not be that scary, it may be considered as two well made bevel gears. Once you have a set-up with all the angles etc. you can repeat as many times as needed. A Hirth coupling may be easier and more precise than a half round joint.

When you do the layout, check the size of the gear teeth. If you find a convenient DP or CP or Module gear size, this may have an influence on the model scale.

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 09:02:25 PM
Coupling concept, obviously it would need a key on the gear of some sort
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 09:08:17 PM
Na ..... Hirth coupling in place of the half rounds.

Is this still a "momentary lapse of reason"? It seems to be taking on permanent roots.

Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 09:14:04 PM
We'll call it two guys talking feasibility.......  8-).....and yes, the roots are getting deeper

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 09:17:55 PM
something like this?

http://image.slidesharecdn.com/couplings-121226211146-phpapp02/95/couplings-8-638.jpg?cb=1356556550

Dave
Title: Re: Momentary lapses of reason......
Post by: crueby on July 08, 2016, 09:24:02 PM
We'll call it two guys talking feasibility.......  8-).....and yes, the roots are getting deeper

Dave

Fascinating conversation to be following, even if I need to google some of the terms flying back and forth. Never heard of hirth coupling, for one. Hope you guys actually build one/some of these engines, as long as you post pictures!!   :popcorn:
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 09:24:18 PM
Yes, it's like two bevel gears made with a 90 degree Vee cutter. Easier to make than the manufactures let on.

Key on the separate gear wheel supported by the adjacent big end bearings, as in your sketch.

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 09:28:45 PM
We'll call it two guys talking feasibility.......  8-).....and yes, the roots are getting deeper

Dave

Fascinating conversation to be following, even if I need to google some of the terms flying back and forth. Never heard of hirth coupling, for one. Hope you guys actually build one/some of these engines, as long as you post pictures!!   :popcorn:

crueby....right now its more two guys having a pint....but you never know!....Mike has "Eatin this dirt" already...so it's good to bounce ideas around.   That way I can all my OWN mistakes.....8-)

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 09:31:44 PM
Yes, it's like two bevel gears made with a 90 degree Vee cutter. Easier to make than the manufactures let on.

Key on the separate gear wheel supported by the adjacent big end bearings, as in your sketch.

Mike

OK you sold me!   Two 3 throws seem a lot easier than 1 six throw!

Next pint is on me!!!

 8)

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 09:34:39 PM
Nice one :DrinkPint: Thanks
Mike
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 09:41:27 PM
I would be inclined to look at the camshaft gear train next. Ideally, you should try to use standard involute cutters or gear hobs rather than be forced into making some odd ball size. This may influence the final scale. :noidea:
Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 09:46:02 PM
YES!   Hence starting at the crank and working out...that will drive the internals...and the scale...

Riddle me this?     the gear drive is slightly asymmetric......how come?

I suspect it was to get the cam box up to the same level as the engine block for ground clearance.....the 917 looks big....but it's not!....

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 09:58:48 PM
Of do you think it has more to do with the difference in size between the exhaust and intake valves?

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 10:08:11 PM
If I told you the answer to that riddle, I would then have to shoot you; it's that secret.

Actually I am not sure. Even if the exhaust cam box were identical to the Inlet it would still be above the level of the lower crankcase seam split. Besides, the snake pit of exhaust pipes are even lower than the crankcase.

Could the asymmetry be there to prevent resonance in the drive train and between the two camshafts, each camshaft runs 'half a tooth' out from each other? Just thinkin.

Mike
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 10:12:16 PM
Don't think they would design the whole cam box asymmetrically because of different lengths of the valves. Porsche could afford to buy/make valves to fit. I guess the asymmetry has much more subtle roots than that.
Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 10:26:22 PM
No so much length of the valve, but valve head diameter....you need to lay it over to get those two HUGE valves in there....and have some meat in between them to put in a Titanium seat and have a head gasket land......I think THAT is the reason....

By the way ....the 0.3 scale engine has a intake valve of 0.625" and an exhaust valve of 0.50
With a cylinder bore of 1"


Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 10:45:46 PM
You sure you are right, I think you have nailed it.
I just noticed the angle of the inlet is much steeper (nearer to the vertical) than the exhaust, in order to accommodate the oversize inlet valve head. The two cam box positions merely reflect the different valve angles. Porsche really had to work hard using different valve angles to get such large valves into the head. Just as well they settled for two valves per cylinder when most race engines, on this side of the Ocean, usually have four valves per cylinder.

Mike
 :cheers:
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 10:47:27 PM
The big gear in the opening graphic for this thread works out to 2" in Outside diameter.    That could be a 64 tooth 32 DP gear which would be robust!....with a 40 tooth crank gear.   going to a 28 tooth gear, then two idlers, and then to a another 35 on the cam shaft

So that is 64/40 x 35/28 =2/1

1/8 scale 2 HP 4x4 Remote control buggy runs 32 DP gears open at 25000 RPM....so clean and oiled, should be fine for demonstration runs
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 10:57:13 PM
My last calculation young man is you're 5 hours ahead of me....it's past your bed time!!!

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 08, 2016, 11:09:08 PM
Yes, it's past bed time but this stuff is so interesting. And less of the 'young man'  please.     :old:

Looking again at the hellafunctional website. The big wheel looks to have something like 56 teeth, Porsche would have used a module gear form rather than DP. However 32DP would work just as well, especially if you already have the cutters available.

Till tomorrow

Mike
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 11:14:04 PM
Yes, it's past bed time but this stuff is so interesting. And less of the 'young man'  please.     :old:

Looking again at the hellafunctional website. The big wheel looks to have something like 56 teeth, Porsche would have used a module gear form rather than DP. However 32DP would work just as well, especially if you already have the cutters available.

Till tomorrow

Mike

Sir!  Yes Sir!


Yes   I think I have some 32 DP cutters...so it's promising.....the biggest thing I think we accomplished today is ....it's not that unreasonable!....dare I say   maybe even doable!!!!


Tomorrow IS another day!     Have a good night my friend!    :DrinkPint:

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 08, 2016, 11:18:58 PM
PS   Thank you for a fun and very informative and constructive conversation!   I enjoyed it no end!... :praise2:

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 09, 2016, 12:59:45 PM
The next thing to have me noodling is the cam timing...is it intended to be brought into proper time by shifting the cam drive gears on the cam shaft with a bunch of index holes on the cam and the second gear on the cam drive?

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 09, 2016, 02:39:12 PM
Well, if you have a full size 917 and intent on extracting every last ounce of torque and fraction of a horsepower, then vernier adjustment of the camshaft timing would be important.
For a model demonstration runner I would have thought the main requirement would be for ease of starting and reliable operation. This could be achieved by the use of conservative valve timing without much overlap, reduced valve lift, perhaps smaller diameter valves and a lower CR. The smaller valves would also allow the use of a screw in cage rather than a valve seat insert.
Ease of manufacture and ease of operation being the main requirement. The conservative valve timing events would be well within 'normal' machining limits for a fixed cam/gear. I would also think about reducing the CR  as appropriate for the type of fuel to be used.

Just my initial thoughts.

Mike

PS.     Hamilton on pole for the British GP tomorrow.
Title: Re: Momentary lapses of reason......
Post by: steamer on July 09, 2016, 03:02:16 PM
Agreed on all points....CR of about 6.5/1 or so?    Makes ignition requirements a bit easier too I would think

I ask as I wanted to understand how the real one did it.    To your point though, getting rid of that joint would be a good thing and gets rid of a potential problem

1/2" and 3/8 intake and exhaust perhaps....too soon to tell.... it would need to be laid out for sure.

I guess you answered the question though...with reduced "aggressiveness" of engine timing, timing the cams shouldn't be a problem...within a gear tooth anyway.

Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 09, 2016, 03:05:13 PM


PS.     Hamilton on pole for the British GP tomorrow.

Was there any doubt?   8-)
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 09, 2016, 03:21:11 PM
The 917 engine is just a Beetle engine on steroids. You can get a good look at the external oil pipe plumbing in your latest photo.

With 120cc or so to play with, you could use 'farm engine' valve timing to make an easy handling engine. It will still sound impressive enough.
CR 6.5:1 on gasoline, CR 8.5:1 on alcohol not sure about propane or even how you could use it.

Mike

Unfortunately Mercedes seem bent on having a German World Champion in a German car. They could still nobble Hamilton with technical problems or poor race tactics yet again.
Title: Re: Momentary lapses of reason......
Post by: steamer on July 09, 2016, 03:28:43 PM
I'd think ANY 12 will sound awesome!     :Lol:

Yes the political drama of F1 is amazing...Some of the "out of bounds" rules they've come up with seem draconian .....

Let em Race!

Dave
Title: Re: Momentary lapses of reason......
Post by: Jo on July 09, 2016, 04:33:41 PM
PS.     Hamilton on pole for the British GP tomorrow.

 :Mad: I have qualifying recorded for after dinner :cussing:  :cussing:  :cussing:

Jo
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 09, 2016, 04:49:44 PM
Jo,      Just sit back and enjoy the third qualifying session with a glass in your hand. Sorry if I let the cat out of the bag for you

Mike
Title: Re: Momentary lapses of reason......
Post by: Jasonb on July 09, 2016, 08:04:17 PM
Ah Jo, a true fan would have watched it live ;)

Mike good bit of downhill this afternoon, did not expect that :) Though that crouched down on the top tube position looks painful :-[
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 09, 2016, 08:33:24 PM
Yes, an incredible down hill finish for today's stage of the Tour De France. Froome caught the whole field napping. He developed that painful 'over the handlebars crouch' in the wind-tunnel. It puts more weight over the front wheels so he can get round the down hill hairpin bends faster.

Mike
Title: Re: Momentary lapses of reason......
Post by: Jo on July 10, 2016, 05:04:26 AM
Ah Jo, a true fan would have watched it live ;)

A true fan would be at Silverstone this weekend    :stickpoke:

Those of us who can't can make the most of the weekend in the garden/workshop and watch it at our leisure  ;)

Jo
Title: Re: Momentary lapses of reason......
Post by: steamer on July 12, 2016, 01:10:02 AM
OK Mike.....Those spiral worm gear drives for the distributor.    Do you recommend  the "Westbury" trick to cut them?  or do you have another trick up your sleeve?


never mind.......like this
http://modelenginenews.org/index.html




Dave
Title: Re: Momentary lapses of reason......
Post by: steamer on July 12, 2016, 04:09:01 AM
I think I sorted the oil plumbing tonight.....a bit of clever, and deep!   gun drilled holes in the case..

The model should be FUN! :o

Dave
Title: Re: Momentary lapses of reason......
Post by: Vixen on July 12, 2016, 10:31:59 AM
Unfortunately I do not have much experience in making spiral worm gears and non at all with "Mr Westbury's" tricks.

Did you post the correct link? I was taken to the farewell post from our dear departed friend Ron. Such grace and dignity knowing everything would end in just a few short, painful weeks.

RIP Ron, your memory lives on.

Mike

Title: 917 180 degree V 12
Post by: steamer on July 12, 2016, 12:25:13 PM
Hi Mike,

Yes, I always loved his editorials!     The page I hoped I was linking, but apparently failed to ...is on that page

Look under Engines

Then Projects

Then look under the "Feeney" project, and he explains a very simple means of cutting these gears.   It was actually published in Home Shop Machinist, and I remember the article.

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on July 12, 2016, 01:55:55 PM
Dave
I know we have both been looking at the oil system plumbing for the Porsche 917 engine. The oil system is well integrated into the bowls of the engine and not that easy to understand, given the limited drawings available to us. There are many photos on Google but usually of the different parts of the engine to that you wish to study. It will take some engineering detective work and plenty of discussion to work things out. It would be a great help if one of the forum members had a Porsche 917 sitting in the garage, but perhaps that is too much to wish for.

In a high performance racing engine the oil system performs two major tasks. The lubrication of the bearings is obvious, the use of the oil to remove heat and cool the engine may not be so obvious. The oil system plays a major role in the cooling of an air cooled engine, more so than in a liquid cooled engine. Most high performance race engines do not have an oil sump (oil pan), instead a so called a dry sump system is used. The engine's hot, used oil is sucked out of the bottom of the engine by large scavenge pumps and pumped through large oil coolers into a header tank. The cooled and de-aerated oil returns to the engines pressure pump for re-circulation.

Three large volume pumps can be seen in the cross section drawing. One pressure pump and two scavenge pumps. The pump block is sandwiched between the two halves of the crankcase. Oil passages have been gun bored (drilled) into the crankcase casting walls, the bumps associated with these oil passages can be seen in the photos shown in reply #  53. All three pumps, pump from right to left.

If you look at the cross section drawing in the first post, you can see there are four circular oil passages (drillings) in the crankcase. Three on the left half and one on the right. The oil passage in the bottom right corner connects the oil suction strainers to the inlet side of the scavenge pumps. The hot oil from the scavenge pumps exits via the lower left oil passage on the left side of the crankcase. The high pressure oil from the pressure pump connects to the middle left drilling. There is another vertically drilled passage (can be seen on several of the Porsche museum exploded engine display photos) which connects the lower left oil passage to the the full length oil passage at the top left hand corner on the crankcase. The high pressure oil is distributed down smaller drillings to each of the eight main bearing journals. More small drillings in the crankshaft distribute the oil to the big end bearings. All quite conventional but needs to be fully understood to design the model engine.

The oil feed to the four camshafts is not so easy to trace. There are no drawing and the available photos never seem to show the detail we are looking for. There is an interesting series of engine part photos on the https://www.classicdriver.com/en/car/porsche/917/1970/171074 website. One shows the cambox lower shelf, without the camshaft in place. There appear to be no oil passage drillings into the camshaft bearing journals. I have therefore assume that the camshaft lube oil passes down a drilling in the centre of the hollow camshaft instead of through oil passages in the cambox tray. I am not absolutely certain how the high pressure lube oil reaches the four camshafts, but there appears to be an oil way drilled in both of the camshaft drive gear cluster housings, between the crankcase oil passage and the camboxes.

Waste oil from the four cam boxes is scavenged by another two oil pumps driven off the ends of the lower camshafts. The camshaft scavenge oil is returned to the front of the engine via the two external pipes.

Well that's how I interpret the limited information available. Dave may have reached different or similar conclusions, Either way, by this sort of engineering detective work, we slowly begin to understand what made the Porsche 917 so remarkable.

Mike



Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 02:14:53 PM
Hey Mike,

I believe the pumps work just as you say.   What I saw last night is ....I think.....they come out of the pump and both feeds make a 90 degree turn to the front of the engine.  Through two separate gun drilled holes.     One from the scanvenge pumps goes back to tank as you have mentioned.   I believe the pressure side turns vertical at the front of the engine and goes to an oil filter at the top front of the engine.   From there, it flows back along the top of the engine towards the back of the engine.     From there I think it feeds the mains as you say.   and there appears to be a cross over between the cases that feeds passages in the cam gear box assemblies.    If you look you will see two hollow location pins on the gear cases, and an oil passage down the side...it is often plugged with a plastic plug cap in the photo's     You can also see the cross over port from the left case to the right case for the camshafts just behind the bore for the cooling fan shaft, just below the stud in the casing.

OK  so we've gotten as far as the top of the of the cam shaft gear boxes, both sides..... 

What I see....and perhaps I'm not seeing it correctly so I'll call it surmise....

There are two gun drilled passages either side of the cam shafts on the cam box, connected to the one feed port coming from the cam shaft gear boxes.

They are connected via two cross drilled ports.    This feeds all the camshaft bearings from below.     I also believe we see oil nozzles that feed oil to the cam/tappet pockets...this would cool and lubricate this part of the engine nicely....

See if you can see what I see....if you like..      I need to go make a living.....but I'll be back later... 8)

Having great fun!

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 02:19:18 PM
Mike...the pictures I was looking at were of the engine in the Porsche museum....the "Exploded view" engine

https://www.classicdriver.com/en/car/porsche/917/1970/171074
The reference you gave...doesn't show oil feed holes to the cam shaft bearings, but I did see them in the other engine.

A design change perhaps?

Dave
Title: Re: 917 180 degree V 12
Post by: b.lindsey on July 12, 2016, 02:19:44 PM
Hmmmm...twelve pages and not one chip yet. You have been around Zee to long Dave  :lolb:

Bill
Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 02:25:54 PM
Hmmmm...twelve pages and not one chip yet. You have been around Zee to long Dave  :lolb:

Bill

This would be called the Engineering phase of the project.    Personally, I think it's a great tool for the design of a model.   How did the real one work, and how do you figure it out?  How do you go about designing a model...and documenting the design so that you can go in the shop and make it....

Additionally, I'm enjoying myself...and I think Mike is as well.....

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 02:28:07 PM
Mike...

I blew up the photo from your reference....and took a snap shot and annotated it.

I think it does have oil holes, it's that the picture is low resolution...but I think I can make them out.....here's my retouched photo with a sketch on it.

I've circled what I think are the oil holes.....they appear at least consistent.

Dave
Title: Re: 917 180 degree V 12
Post by: b.lindsey on July 12, 2016, 02:31:25 PM
I am just messing with you Dave. For a project this complex you are absolutely right :)

Bill
Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 02:32:49 PM
Thanks  Bill!   

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on July 12, 2016, 02:36:07 PM
Dave,
That's the big problem with this sort of detective work. Which piece of information is correct, which can you trust when you only have Google to find stuff. There were many different versions produced by the factory and the available documentation does not record version number or modification state. Similarly, many engines are in private hands and we have no idea what extra modifications were added by the new owners.

The best we can hope to achieve is an understanding of the approach taken by the designer and from this devise something similar which can be made to work for our model engines. We can work to produce a fine look alike engine from the limited information available but you would need access to a full set of works drawings to produce an exact replica.


Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 02:38:20 PM
Dave,
That's the big problem with this sort of detective work. Which piece of information is correct, which can you trust when you only have Google to find stuff. There were many different versions produced by the factory and the available documentation does not record version number or modification state. Similarly, many engines are in private hands and we have no idea what extra modifications were added by the new owners.

The best we can hope to achieve is an understanding of the approach taken by the designer and from this devise something similar which can be made to work for our model engines. We can work to produce a fine look alike engine from the limited information available but you would need access to a full set of works drawings to produce an exact replica.

1000% correct on all accounts!    We progress......

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 02:40:04 PM
Here's the engine build from another site....same part.    showing oil ports...
Title: Re: 917 180 degree V 12
Post by: Vixen on July 12, 2016, 02:43:54 PM
Dave,
I looked at your marked up print. I agree I believe you have found the oil drillings for the camshaft bearings. I also believe you can see the shape of the full length oil passage under your red line. Nothing wrong with listening to another opinion and revising your own thoughts. That's team work.

Mike

Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 02:47:23 PM
In any case......I think this is a viable solution for the model...at least as far as lubricating the cam shaft bearings....the other approach would be to run the cam shaft on ball bearings instead, an thus avoid the need for this extra plumbing...but we need a good way to lube the cam lobe/tappets, and it appears that they accomplished this and is shown in the same photo.

Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 02:48:03 PM
Dave,
I looked at your marked up print. I agree I believe you have found the oil drillings for the camshaft bearings. I also believe you can see the shape of the full length oil passage under your red line. Nothing wrong with listening to another opinion and revising your own thoughts. That's team work.

Mike

 :ThumbsUp: :ThumbsUp: :ThumbsUp: :ThumbsUp: :ThumbsUp:
Title: Re: 917 180 degree V 12
Post by: Vixen on July 12, 2016, 02:53:59 PM
Good progress,
Your on your own for a bit. I am going downstairs to watch the last hour of today's stage of Le Tour.
Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 02:55:12 PM
If I were a betting man....I would bet the "nozzle" just to the side of the tappets has a orifice drilled in it to allow a certain amount of oil to flow to each tappet, and I would bet it's in the form of a cap screw with a seal washer...the thickness of which you adjust to get it aimed right.....

I think for a working model, doing demo runs, some dribbling on the moving parts is more than sufficient.....we can figure that one out.....

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 02:59:35 PM
case pressure oil feed path......I think.

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on July 12, 2016, 03:13:52 PM
Dave, that's how I read the crankcase plumbing. We are in agreement and it looks possible to copy at 1/3 ish scale.

The camshaft oilways may be a bit more tricky in small size.

 Not sure the oil filter was fitted to all the earlier versions, perhaps only the later and Can Am engines.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 03:22:44 PM
oil filter    69'

Title: Re: 917 180 degree V 12
Post by: Vixen on July 12, 2016, 05:47:01 PM
If we keep looking in the right places we will find all the answers.

The problem is always in finding the right places.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 12, 2016, 06:11:17 PM
If we keep looking in the right places we will find all the answers.

The problem is always in finding the right places.

Mike

 8)
Title: Re: 917 180 degree V 12
Post by: Niels Abildgaard on July 12, 2016, 07:15:56 PM
Crankshaft parts rom a Hirth HM504 aircraft engine
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on July 12, 2016, 09:58:22 PM
While googling this subject I stumbled over those two engines :

http://blog.hemmings.com/index.php/2015/10/30/kinetic-sculpture-internal-combustion-style-modeling-the-porsche-904-and-917-engines/ (http://blog.hemmings.com/index.php/2015/10/30/kinetic-sculpture-internal-combustion-style-modeling-the-porsche-904-and-917-engines/)

Sorry - but no pressure Dave
Title: Re: 917 180 degree V 12
Post by: steamer on July 13, 2016, 02:31:27 AM
While googling this subject I stumbled over those two engines :

http://blog.hemmings.com/index.php/2015/10/30/kinetic-sculpture-internal-combustion-style-modeling-the-porsche-904-and-917-engines/ (http://blog.hemmings.com/index.php/2015/10/30/kinetic-sculpture-internal-combustion-style-modeling-the-porsche-904-and-917-engines/)

Sorry - but no pressure Dave

Couple of things...that is 1/4 scale...I'll be 3/10    larger still      That didn't have an output shaft off the crank....kinda odd.....Mine will...like the real 917.

No pressure at all!   I'm having fun...but I have a Wallaby to build first!....

Dave
Title: Re: 917 180 degree V 12
Post by: Art K on July 13, 2016, 03:49:21 AM
Dave,
That Wallaby gives you time to think about the 917. Poor Wallaby relegated to distraction while you figure out the flat 12.
Art
Title: Re: 917 180 degree V 12
Post by: steamer on July 13, 2016, 04:10:16 AM
Dave,
That Wallaby gives you time to think about the 917. Poor Wallaby relegated to distraction while you figure out the flat 12.
Art

Well ......Life in the big city......
Title: Re: 917 180 degree V 12
Post by: steamer on July 21, 2016, 04:46:18 AM
roughed out a crank.....

Title: Re: 917 180 degree V 12
Post by: Vixen on July 21, 2016, 08:53:08 AM
That looks to be a mighty robust crankshaft. Some of the photos seem to show the shape of the counterweight are different depending on their position, But I now see you are looking at that already.
Are you still thinking about making the crank in two halves, joined in the centre under the gearwheel?
If you decide to use a Hirth coupling, a common method is to pull the two halves together with a central 'bolt'. The 'bolt' usually has a left and right hand thread and is normally tightened by a spline or hex in the centre of the hollow 'bolt'

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 21, 2016, 12:11:10 PM
Just drawing up what I see.   Probably split it in the center with a hirth.
Title: Re: 917 180 degree V 12
Post by: steamer on July 21, 2016, 01:21:40 PM
On the other hand.......it IS a beefy crank!!!....

It scales at .500" mains with .4375 throws with a 0.8125 stroke

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on July 21, 2016, 03:22:46 PM
Here we have the classic problem of obtaining information from the internet for an engine that has seen many years of development changes. Compare the last photo you posted with the crankshaft in this photo

(http://i901.photobucket.com/albums/ac218/v8vixen1/21844550.Casewithdist.shaftdriveshaftandfandriveinstalled_2.jpg)

The shape of the counterweights of the inside webs are quite different. Both are correct, but clearly from different times in the engine's development history. Unless you have access to an individual engine, an exact replica may not be possible.
With the information resources available to us and the need to make the engine do-able in the home shop, the best we can hope for is a near scale model.
That said, a near scale model of the Porsche 917 engine is going to be something mighty special, an incredible challenge both to design and to make. But what an engine it would be when you get there.
Stick with it Dave.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 21, 2016, 03:30:14 PM





Here we have the classic problem of obtaining information from the internet for an engine that has seen many years of development changes. Compare the last photo you posted with the crankshaft in this photo

(http://i901.photobucket.com/albums/ac218/v8vixen1/21844550.Casewithdist.shaftdriveshaftandfandriveinstalled_2.jpg)

The shape of the counterweights of the inside webs are quite different. Both are correct, but clearly from different times in the engine's development history. Unless you have access to an individual engine, an exact replica may not be possible.
With the information resources available to us and the need to make the engine do-able in the home shop, the best we can hope for is a near scale model.
That said, a near scale model of the Porsche 917 engine is going to be something mighty special, an incredible challenge both to design and to make. But what an engine it would be when you get there.
Stick with it Dave.

Mike
Ya damn Skippy I will!
Title: Re: 917 180 degree V 12
Post by: steamer on July 21, 2016, 04:21:06 PM
And oh by the way......Mike, What has made this so enjoyable thusfar has been our wonderful discussions!   Please!   Keep dropping by!    I enjoy your input! :praise2: :praise2:



Dave
Title: Re: 917 180 degree V 12
Post by: Jo on July 21, 2016, 04:34:05 PM
Talking cranks I found a picture of an embryo crank just now:

(http://i164.photobucket.com/albums/u27/mcandrew1894/Family/IMG_20140317_2146413611_zps292ce987.jpg)

I was wondering what it looks like today :noidea:

Jo
Title: Re: 917 180 degree V 12
Post by: steamer on July 21, 2016, 04:42:57 PM
About the same.   Got some time coming in august jo
Title: Re: 917 180 degree V 12
Post by: Vixen on July 21, 2016, 04:44:09 PM
Jo
That's how most of my engines parts start out, as a block of material.
Sometimes the block is bigger, sometimes it's smaller, sometimes there is just a lump of misshapen scrap inside, but the reward comes when you find a perfect engine part hidden inside.
By the way, castings are rarely harmed in my workshop.

Just teasing

Mike
Title: Re: 917 180 degree V 12
Post by: Vixen on July 21, 2016, 05:08:30 PM
Dave,
Kundensport are a specialist vehicle restoration/ race car preparation outfit. Do you think the crankshaft photo you posted earlier may be a modern 'special' ? The dark colouring of the crank webs suggests nitriding, I do not think that was standard Porsche practice back in the late sixties/ early seventies. I could be wrong yet again.

Mike
Title: Re: 917 180 degree V 12
Post by: Jo on July 21, 2016, 05:50:19 PM
By the way, castings are rarely harmed in my workshop.

Castings are not harmed in my workshop :hellno:

Post the very important fondling stage they venture out into the workshop to be transformed. I used to find, before I realised the importance of casting fondling, that sometimes I would get different features than shown on the drawing  ::).

Jo
Title: Re: 917 180 degree V 12
Post by: steamer on July 21, 2016, 05:51:17 PM
Been thinking about that Mike.  Is bet the photo I posted was to a turbo 917.     It would make perfect sense.
Title: Re: 917 180 degree V 12
Post by: Vixen on July 21, 2016, 06:13:20 PM


 I used to find, before I realised the importance of casting fondling, that sometimes I would get different features than shown on the drawing  ::).

Jo

Ha ha, Perhaps I have been missing out on that obviously important stage of casting fondling. Somehow it does not feel right to do it with a solid billet of steel. May give it a try when nobody is looking.

Mike
Title: Re: 917 180 degree V 12
Post by: Vixen on July 21, 2016, 06:21:28 PM
Been thinking about that Mike.  Is bet the photo I posted was to a turbo 917.     It would make perfect sense.

Dave, you could be right about it being from a 1,500 HP Turbo 917. That crankshaft could well be an aftermarket product used to rebuild an original engine to make it more bomb proof.

Who you going to trust?

Mike

Title: Re: 917 180 degree V 12
Post by: steamer on July 21, 2016, 07:13:17 PM
Been thinking about that Mike.  Is bet the photo I posted was to a turbo 917.     It would make perfect sense.

Dave, you could be right about it being from a 1,500 HP Turbo 917. That crankshaft could well be an aftermarket product used to rebuild an original engine to make it more bomb proof.

Who you going to trust?

Mike




 :lolb:.....My stock rack!!!!!    :ROFL:

It's going to be a heavy crank.   Even if it wasn't it'd need a big flywheel, so I don't see an issue with a big heavy crank.

Dave
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on July 21, 2016, 10:47:10 PM
Dave - are going to make it a two part crank with a Hirth-joint ?

If so - I would personally consider a three part crank, with the gear in the middle as the third part. It would admittedly require the double amount of Hirth-joints - but it would make the gear a lot easier and both cranks can probably be identical ....

Just an idea.
Title: Re: 917 180 degree V 12
Post by: steamer on July 22, 2016, 06:10:08 AM
Maybe Admiral,   I just might make it 1 piece and cut the gear in place.

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on July 24, 2016, 01:55:57 PM
Hey Mike,

What would you think of 4 carburetors, centered in the middle of a group of 3 intake stacks.   The stacks either side of which would be dummies and blocked off.   Then put a transfer port in where the slide throttle would go.....

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on July 24, 2016, 03:37:15 PM
Dave,

Four carburetors, each feeding three cylinders, would be an elegant technical solution. Better technically, perhaps, than two carbs, disguised as turbos, feeding each bank of six cylinders. Although the dummy turbo route could be made to look more realistic. In the end it will be down the aesthetics, which solution looks best and most like a Porsche 917?

What sort of carburetor are you thinking of, and how difficult will it be to disguise them? I have found the rotating barrel (not butterfly) type of Walbro carburetor, to be very stable and reliable. Unfortunately the diaphragms do not like methanol being designed for gasoline. Keep the carburetor bore small if you want an easy handling engine, you are not trying to produce hundreds of horsepower.

Mike
Title: Re: 917 180 degree V 12
Post by: gerritv on July 24, 2016, 03:43:47 PM
While searching for something completely unrelated, I came across this interesting description of making camshafts.

Page 175  of Machinery Volume 28, 1922 (https://books.google.ca/books?id=jwU0AQAAMAAJ) has a complete schedule of operations. Seems worth creating a set of indexing plates to do the required machining.

Gerrit
Title: Re: 917 180 degree V 12
Post by: steamer on July 24, 2016, 03:58:05 PM
Hey Gerrit....I'll probably use cam calc when the time comes...

Though and index plate showing where the events are would be useful to avoid indexing errors..

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on July 24, 2016, 04:00:20 PM
There may be an opportunity for the use of the air boxes......

http://www.porsche917.com.ar/ZTecmotor06.JPG

Though having the bare velocity stacks is more attractive to my eye...

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on July 24, 2016, 04:02:23 PM
Dave,

Four carburetors, each feeding three cylinders, would be an elegant technical solution. Better technically, perhaps, than two carbs, disguised as turbos, feeding each bank of six cylinders. Although the dummy turbo route could be made to look more realistic. In the end it will be down the aesthetics, which solution looks best and most like a Porsche 917?

What sort of carburetor are you thinking of, and how difficult will it be to disguise them? I have found the rotating barrel (not butterfly) type of Walbro carburetor, to be very stable and reliable. Unfortunately the diaphragms do not like methanol being designed for gasoline. Keep the carburetor bore small if you want an easy handling engine, you are not trying to produce hundreds of horsepower.

Mike

I would probably run this engine on Gasoline anyway....Some Cam 2 perhaps....for the right "smell"....Nothing like the smell of 120 octane in the morning....though at about $10/gallon.....
Title: Re: 917 180 degree V 12
Post by: Vixen on July 24, 2016, 04:25:17 PM
Quote
....for the right "smell"....Nothing like the smell of 120 octane in the morning....though at about $10/gallon.....

Well there is perhaps that smell of marzipan (almonds) from a Mercedes Silver Arrows burning a cocktail of Nitro Benzine, Acetone, Ether and a little Methanol at 2 miles per gallon. It makes your eyes water and your heart beat faster.

Mike
Title: Re: 917 180 degree V 12
Post by: b.lindsey on July 24, 2016, 04:38:32 PM
Quote from: steamer
[/quote

I would probably run this engine on Gasoline anyway....Some Cam 2 perhaps....for the right "smell"....Nothing like the smell of 120 octane in the morning....though at about $10/gallon.....

About the same as Coleman fuel Dave. You get this project done and I am doubting the fuel cost will be of much concern.  ;D

Bill
Title: Re: 917 180 degree V 12
Post by: steamer on July 24, 2016, 04:42:11 PM
Quote from: steamer
[/quote

I would probably run this engine on Gasoline anyway....Some Cam 2 perhaps....for the right "smell"....Nothing like the smell of 120 octane in the morning....though at about $10/gallon.....

About the same as Coleman fuel Dave. You get this project done and I am doubting the fuel cost will be of much concern.  ;D

Bill

Yeah....but Cam2 just has that smell!.....Bubba knows what Im talking about....
Title: Re: 917 180 degree V 12
Post by: steamer on July 24, 2016, 07:47:12 PM
This might do the trick......

http://www.model-engine-plans.com/engineplans/combustion/howell2jet.htm?22,20

Dave
Title: Re: 917 180 degree V 12
Post by: stevehuckss396 on July 24, 2016, 08:09:37 PM
Quote from: steamer
[/quote

I would probably run this engine on Gasoline anyway....Some Cam 2 perhaps....for the right "smell"....Nothing like the smell of 120 octane in the morning....though at about $10/gallon.....

About the same as Coleman fuel Dave. You get this project done and I am doubting the fuel cost will be of much concern.  ;D

Bill

Yeah....but Cam2 just has that smell!.....Bubba knows what Im talking about....


Yes I do!!

Turbo Blue is only $7.00 a gallon. Cheaper than Coleman and smells way better!
Title: Re: 917 180 degree V 12
Post by: steamer on July 24, 2016, 08:47:00 PM
Quote from: steamer
[/quote

I would probably run this engine on Gasoline anyway....Some Cam 2 perhaps....for the right "smell"....Nothing like the smell of 120 octane in the morning....though at about $10/gallon.....

About the same as Coleman fuel Dave. You get this project done and I am doubting the fuel cost will be of much concern.  ;D

Bill

Yeah....but Cam2 just has that smell!.....Bubba knows what Im talking about....


Yes I do!!

Turbo Blue is only $7.00 a gallon. Cheaper than Coleman and smells way better!

Awesome!!!!
Title: Re: 917 180 degree V 12
Post by: steamer on July 25, 2016, 11:32:19 AM
This might do the trick......

http://www.model-engine-plans.com/engineplans/combustion/howell2jet.htm?22,20

Dave

bought the plan set for the V Twin.....NICE...   These carbs would do it I think.    We progress!


Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on July 25, 2016, 03:55:01 PM
Do you intend to fit the carbs with remote float chambers or will you try to run them direct from a single fuel tank?

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 25, 2016, 07:46:03 PM
I'll need all the help I can get, so a elevated day tank with a float leveling valve big enough to handle the engine.....I think.

Dave
Title: Re: 917 180 degree V 12
Post by: gerritv on July 25, 2016, 08:22:36 PM
Hey Gerrit....I'll probably use cam calc when the time comes...

Though and index plate showing where the events are would be useful to avoid indexing errors..

Dave
My intention was to show a manufacturing process that seems doable in a home shop, not for the timing aspects. A cam of 917 complexity would seem to need something along those lines.

Gerrit
Title: Re: 917 180 degree V 12
Post by: steamer on July 25, 2016, 08:40:09 PM
Hey Gerrit....I'll probably use cam calc when the time comes...

Though and index plate showing where the events are would be useful to avoid indexing errors..

Dave
My intention was to show a manufacturing process that seems doable in a home shop, not for the timing aspects. A cam of 917 complexity would seem to need something along those lines.

Gerrit

Understood Gerrit!...Milling lobes using the camcalc program is very similar to the article that you referenced.    It does help a lot in planning the cuts and the index head, as it spits out the moves to get where you need to go.  However, having a reference chart on the cam blank with the timing events helps keep you from being too "human".....I'll need all the help I can get!!!!    Thanks for you interest!!. :praise2:
Title: Re: 917 180 degree V 12
Post by: steamer on July 28, 2016, 01:14:05 AM
dry Sump System

http://www.aviaid.com/pdfs/dsp_install.pdf

Dave
Title: Re: 917 180 degree V 12
Post by: stevehuckss396 on July 28, 2016, 01:27:25 AM
My intention was to show a manufacturing process that seems doable in a home shop, not for the timing aspects. A cam of 917 complexity would seem to need something along those lines.
Gerrit


What makes a 917 cam more complex than a cam in any other engine?  Just wondering.
Title: Re: 917 180 degree V 12
Post by: steamer on July 28, 2016, 01:35:36 AM
The only weird thing about this cam is the timing gear in the middle, and the ends of the bottom cams drive oil scavenging pumps....but in and of itself....I don't think it's that bad.


Dave
Title: Re: 917 180 degree V 12
Post by: gerritv on July 28, 2016, 01:56:47 AM
My intention was to show a manufacturing process that seems doable in a home shop, not for the timing aspects. A cam of 917 complexity would seem to need something along those lines.
Gerrit


What makes a 917 cam more complex than a cam in any other engine?  Just wondering.
I see a lot of lobes on 4 cams. I would think some jigs would be beneficial to keep things sorted. A cam with 2 lobes is challenge enough for me :-)
Title: Re: 917 180 degree V 12
Post by: steamer on July 28, 2016, 12:09:58 PM
My intention was to show a manufacturing process that seems doable in a home shop, not for the timing aspects. A cam of 917 complexity would seem to need something along those lines.
Gerrit


What makes a 917 cam more complex than a cam in any other engine?  Just wondering.
I see a lot of lobes on 4 cams. I would think some jigs would be beneficial to keep things sorted. A cam with 2 lobes is challenge enough for me :-)

Agreed.     for the record though, it's a 2 valve per cylinder engine....which at least reduces the number of lobes....but to your point Gerrit, staying organized is key!
This "conversation" thread is about the preliminary work.   The engineering of the components and a plan for their execution.    So all valid points!

Steve and I have been having a conversation off line about ignition...or should I say...he's been "learnin" me!   The 917 had dual ignition, with what I suspect were dual magneto distributors.  That would give it lot's of spark power, and be very reliable.       No I'm not going to do a magneto distributor, but I'll post my intentions for dual distributor ignition system.     It's hard to justify taking one of them out, it was such a prominent feature of the engine.   

Challenges:
making a pair of reliable Distributors and plugs  ( Maybe go commercial there)
associated Electronics
right angle helical bevel gear drive for the distributors ( making the gears)
timing the valve train
timing the ignition system
triggering the ignition system.

The above list^^^ and many other challenges are why I've been doodling in this thread.     There's a lot of smart people here.....

This is all the preparatory work that goes into any engineering project.  The bigger the project, the more engineering and planning is required.

 :praise2: :praise2:

Dave


ps....there's always the old saying though......"Everyone has a plan until the first punch!"   8)
Title: Re: 917 180 degree V 12
Post by: steamer on July 31, 2016, 01:02:43 AM
A little doodling.....with my computer.....

It scales pretty close!....

1" bore x 0.812 stroke
40 tooth 32 DP crank and power take off gears.

Crank is about 10" long.....
Title: Re: 917 180 degree V 12
Post by: Mosey on July 31, 2016, 04:08:13 PM
Six double throat miniature Webers? No?
Mosey
Title: Re: 917 180 degree V 12
Post by: steamer on July 31, 2016, 04:33:51 PM
4 Howell carbs, with 8 dummies.......( 1 carb /3 cylinders)......at least that is the plan at the moment.....

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on July 31, 2016, 06:33:06 PM
Sounds like a good plan to me.    :thinking: :thinking: :thinking:

Mike     
Title: Re: 917 180 degree V 12
Post by: steamer on July 31, 2016, 06:35:25 PM
Mike, very preliminary, but nothing that is too difficult.    scaling the drawing has worked pretty well so far.

but it's WAY TOO EARLY...to declare a victory.....


Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on July 31, 2016, 06:38:34 PM
A little doodling.....with my computer.....

It scales pretty close!....

1" bore x 0.812 stroke
40 tooth 32 DP crank and power take off gears.

Crank is about 10" long.....

That looks to be a sound basis for the design. You can add more and more detail as the design progresses. A 3D model which you can rotate and view from any angle will allow you to spot any potential collisions before you commit to cutting metal. Nice work.

Remember it is all about the journey, so enjoy every step

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 31, 2016, 07:05:59 PM
Yes it is about the journey!    AND who you take with you on the trip!!!

The case thus far is a very simple piece...it'll get more complicated as I add detail, but as it's a "prismatic" part, I shouldn't need any super special fixtures....

That crank.....I'm still torn....what I'm going to do is make the Wallaby crank using the method I have in mind, and see how that goes before I decide to make the crank 1 piece or 2 piece.....
Any way you look at it, the oil passages will be ...nerve racking.....

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on July 31, 2016, 07:49:28 PM
Dave
Those oil passages are always nerve racking, even if you have done it many times.
My method is to do it all on the mill, start the oil passage with a 2 or three flute mill cutter of the required diameter and follow with a good quality (new) short stubby drill of exactly the same diameter. Then progress in stages with longer length drills all of the same diameter. I try not to have much unsupported drill exposed because that is where the bend wants to occur. I peck drill and remove the drill to clear the swarf every few mm. My record to date is four 120mm deep, 3mm oil passages which all hit a cross drilling within a few thou.
Yes I know, thous of an inch and mm but I am an engineer so trust me !!!!!!!  :thinking: :thinking: :thinking:

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 31, 2016, 08:32:36 PM
No doubt in my mind Mike!   

I'm going to try to mill the crank from solid ala the Duclos method...then perhaps give it a little lap.   I'll try that on the Wallaby...and see how it goes....

With the 917 crank...there are only 4 centers...so not too bad.

Dave
Title: Re: 917 180 degree V 12
Post by: Tennessee Whiskey on July 31, 2016, 09:17:23 PM
I'm reading this thread like the SI swimsuit edition: can't do anything with it,  but,  sure do enjoy it  :lolb:. Wonder if one of these would come in handy at build time
http://sherline.com/product/8650-cnc-cam-grinder/

Cletus
Title: Re: 917 180 degree V 12
Post by: steamer on July 31, 2016, 09:47:24 PM
Sure would!!!! so would the $3600 too!     I'll mill mine......

Dave
Title: Re: 917 180 degree V 12
Post by: b.lindsey on July 31, 2016, 09:53:43 PM
Sure would make a pretty cam though.  :stir:

Bill
Title: Re: 917 180 degree V 12
Post by: steamer on July 31, 2016, 10:58:42 PM
Sure would make a pretty cam though.  :stir:

Bill

Hey Bill!     That would make a great item as my stocking stuffer!   Christmas is coming!!! hint hint!
Title: Re: 917 180 degree V 12
Post by: stevehuckss396 on July 31, 2016, 11:19:06 PM
Steamer!

Have you looked into offset turning your cam on the lathe? The advantage would be cutting all the lobes at the same time in one 360 degree rotation. Save you a ton of time. Specially if you are doing 4 of them.
Title: Re: 917 180 degree V 12
Post by: steamer on July 31, 2016, 11:59:55 PM
I have , and probably will!    it's a good way to do it!

Dave
Title: Re: 917 180 degree V 12
Post by: b.lindsey on August 01, 2016, 12:40:49 AM
Do I look like Santa Clause  :old:  I may have the figure, but not the beard and my hair ain't white yet   :lolb:

Bill
Title: Re: 917 180 degree V 12
Post by: steamer on November 17, 2016, 12:32:02 AM
Great thread for reference.

4 carbs feeding 12 cylinders......this was described earlier in this thread, and this thread shows this concept working and in action.


http://www.modelenginemaker.com/index.php/topic,4241.60.html

Dave
Title: Re: 917 180 degree V 12
Post by: Mosey on November 20, 2016, 07:31:53 PM
Dave,
Have you seen the "How It's Made" tv show on Discovery where they make a Jaguar crank by cutting the blank from a solid bar with a large diameter toothed cutter in the lathe. The Camshaft is done similarly. One rotation of the blank and a nearly finished crank emerges.
could it be done in the home shop?
Mosey
Title: Re: 917 180 degree V 12
Post by: steamer on November 20, 2016, 07:52:02 PM
Dave,
Have you seen the "How It's Made" tv show on Discovery where they make a Jaguar crank by cutting the blank from a solid bar with a large diameter toothed cutter in the lathe. The Camshaft is done similarly. One rotation of the blank and a nearly finished crank emerges.
could it be done in the home shop?
Mosey


I think you could if your machine is stiff enough.   Additionally, the machine in the video had 2 chucks,  headstock and tailstock.    That would add a lot of stiffness to the system, something traditional centers don't have.

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on June 12, 2017, 08:51:44 PM
http://www.roadandtrack.com/car-culture/buying-maintenance/a9955041/watch-a-porsche-917-flat-12-get-rebuilt-in-three-minutes/


I'm working a lot of hours right now, but I saw this and thought of you guys.....I'll get to it


notice the shims on the cylinder heads to get the cam boxes all aligned?.....

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on June 12, 2017, 11:49:19 PM
A scale model 917..........a dream well worth waiting for.

You will get to start soon enough

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on June 13, 2017, 01:56:29 AM
Thanks for looking in Mike!

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on April 08, 2018, 11:01:28 PM
Hey Mike    what do you think about a slide valve throttle like the original?
Title: Re: 917 180 degree V 12
Post by: b.lindsey on April 09, 2018, 01:02:41 AM
Glad to see you haven't forgotten about this incredible project Dave. Hope your knee lets you gat back to the shop soon.

Bill
Title: Re: 917 180 degree V 12
Post by: Art K on April 09, 2018, 02:14:01 AM
Dave,
Looking at the video it has a standard hemispherical combustion chamber, how hard can that be. :mischief:
Art
Title: Re: 917 180 degree V 12
Post by: Vixen on April 09, 2018, 09:53:43 AM
Hey Mike    what do you think about a slide valve throttle like the original?

Hi Dave,
The twelve inlet stacks with the slide valve throttle block are as iconic as the central cooling fan. They are what makes the 917 road-race engine so exciting to look at. Unfortunately the full size engine had fuel injection and our model will require carbuterrors. Making twelve carbs will be difficult. Making four carbs, each feeding three cylinders may be a little easier.

(http://lister-engine.com/coppermine/albums/userpics/10013/twelve_stack.JPG)


As an alternative you could consider the twin turbo CanAm engine. You could fit a single carburettor in place of the twin turbos. That would be somewhat easier to achieve.

(http://lister-engine.com/coppermine/albums/userpics/10013/turbo.jpg)





But for me that would not have the excitement and visual appear as the Le Mans winning configuration

Design the engine first and worry about the fueling later.

Go on with it, get started. You hear!!

Mike    :zap: :zap: :zap:


Title: Re: 917 180 degree V 12
Post by: Jasonb on April 09, 2018, 10:29:05 AM
Would there be enough height to make round slide valves rather than flat, much like you get on high end RC Car engines? A lot easier to seal and you could have one rod with the six holes in it per side.
Title: Re: 917 180 degree V 12
Post by: Roger B on April 09, 2018, 10:30:41 AM
I think that fuel injection may be possible  :stir: Manifold injection requires a lot less pressure than cylinder injection.
Title: Re: 917 180 degree V 12
Post by: steamer on April 09, 2018, 12:29:32 PM
I think that fuel injection may be possible  :stir: Manifold injection requires a lot less pressure than cylinder injection.


Taking Mikes advice    get on with the design       but you're talking mechanical or electronic fuel injection?

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on April 09, 2018, 12:32:18 PM
Would there be enough height to make round slide valves rather than flat, much like you get on high end RC Car engines? A lot easier to seal and you could have one rod with the six holes in it per side.

That's a solution worth a layout    perhaps with 4 carbs and 8 dummy stacks......
Title: Re: 917 180 degree V 12
Post by: Roger B on April 09, 2018, 12:52:15 PM
Dave, I was thinking mechanical like the original.
I've run mechanical fuel injection into the inlet port of my 25cc engine with success. Now the weather has improved I can re-open my R&D department and carry out some more trials with the helix controlled injection pump. In the video the carb is just being used as a throttle.

http://www.modelenginemaker.com/index.php/topic,4906.0.html

https://www.youtube.com/watch?v=uXUiAfTQvHQ
Title: Re: 917 180 degree V 12
Post by: steamer on April 09, 2018, 01:52:30 PM
Perhaps...though I think getting it running with  carb at least initially would be less traumatizing.... :toilet_claw:

Hmmmm   getting on with the guts first

.812 more 1 stroke
Title: Re: 917 180 degree V 12
Post by: steamer on April 09, 2018, 02:08:08 PM
The 12 inlet stacks is the look I want....
Title: Re: 917 180 degree V 12
Post by: Vixen on April 09, 2018, 02:26:34 PM
Perhaps you could get one injection pump to squirt all 12 stacks simultaneously.

But first you need to get the engine designed.

Mike :noidea:
Title: Re: 917 180 degree V 12
Post by: steamer on April 09, 2018, 02:43:47 PM
 
Perhaps you could get one injection pump to squirt all 12 stacks simultaneously.

But first you need to get the engine designed.

Mike :noidea:


Absolutely.
Title: Re: 917 180 degree V 12
Post by: Roger B on April 09, 2018, 03:04:19 PM
It would be difficult to get even distribution with one pump and 12 nozzles. This chap managed working fuel injection in 1/4 scale for a turbo version.

https://www.classicdriver.com/en/collectible/porsche-type-917-miniature-engine
Title: Re: 917 180 degree V 12
Post by: Vixen on April 09, 2018, 03:08:25 PM
Here's to the rest of the world. I've got a Gulf Porsche 917


(http://i901.photobucket.com/albums/ac218/v8vixen1/steve-mcqueen-the-man-and-le-mans.jpg)

Yeh, way to go

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on April 09, 2018, 03:18:45 PM
I didn't know he was an archer!!!!     8)
Title: Re: 917 180 degree V 12
Post by: michelko on April 09, 2018, 04:26:22 PM
Hi,
have you heared abaout Hubert W. Schillings ? He wrote a book about modelengines in witch he described a mechanical Injektion System with a gear pump. The book is called Boxer-, Reihen- und V-Motoren als Modell.

Michael
Title: Re: 917 180 degree V 12
Post by: steamer on April 09, 2018, 04:53:11 PM
Hi,
have you heared abaout Hubert W. Schillings ? He wrote a book about modelengines in witch he described a mechanical Injektion System with a gear pump. The book is called Boxer-, Reihen- und V-Motoren als Modell.

Michael

Know where I can buy that book?

Dave
Title: Re: 917 180 degree V 12
Post by: gerritv on April 09, 2018, 05:37:37 PM
Publish date was 2001 and seems out of print. It is 62 pages. Abebooks doesn't have it so no used copies about either.
Title: Re: 917 180 degree V 12
Post by: michelko on April 09, 2018, 08:11:25 PM
I have it.
I can send you the pages with the injection, but it is in german. Not realy much information but an idea how to do.

Michael
Title: Re: 917 180 degree V 12
Post by: steamer on April 09, 2018, 08:59:38 PM
I can't do d it in print anywhere.  I'll send a pm.
Title: Re: 917 180 degree V 12
Post by: dieselpilot on April 10, 2018, 06:12:37 PM
VTH.de used to sell the book, they still have the plans.  http://shop.vth.de/einspritzanlage.html All of the photos I've ever seen of Schillings engines seem to have carbs.

Flat slide throttles were also used in RC cars. I have a Picco example.
Title: Re: 917 180 degree V 12
Post by: Jasonb on April 10, 2018, 07:12:14 PM
"this injection test was used to develop the injection system"

You can just see the individual injectors on the engine side of the 4 straight pipes

Second photo is a model of a Daimler Benz 603
Title: Re: 917 180 degree V 12
Post by: Vixen on April 10, 2018, 07:39:11 PM
Jason,

The injection system on that DB603 model is a very crude affair. A single, simple gear pump feeds a constant supply of fuel all the injector nozzles simultaneously via individual check valves. The fuel flow/ pressure is controlled by a by pass valve (needle valve?) which dumps the excess fuel back into the tank. It is all open loop with no throttle control, no speed control, no mass air flow control. It is simply a continuous spray of fuel from all injectors

(http://lister-engine.com/coppermine/albums/userpics/10013/FUEL-INJ.jpg)

It is the equivalent to the needle valve mixture control of a model aircraft engine, without the throttle control. So it is limited to mixture control at flat out running, remember the bladder tanks on racing Doolings

Mike
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on April 10, 2018, 09:51:00 PM
Yes Mike - but he did claim that the leaking of the pump, lowered the pressure enough at lower rpm's that it worked fine over a big range .... or to put it in another way - the pump pressure isn't linear with rpm, but almost linear with demand .... then again it took them some two years to perfect the result .....
Title: Re: 917 180 degree V 12
Post by: steamer on April 11, 2018, 12:03:18 AM
Jason,

The injection system on that DB603 model is a very crude affair. A single, simple gear pump feeds a constant supply of fuel all the injector nozzles simultaneously via individual check valves. The fuel flow/ pressure is controlled by a by pass valve (needle valve?) which dumps the excess fuel back into the tank. It is all open loop with no throttle control, no speed control, no mass air flow control. It is simply a continuous spray of fuel from all injectors

It is the equivalent to the needle valve mixture control of a model aircraft engine, without the throttle control. So it is limited to mixture control at flat out running, remember the bladder tanks on racing Doolings

Mike

Yes but the pump was engine driven, so as Admiral states....it worked...though I share your concern about the crudeness...if I dare call it that ..that must of been a right (@#*  to make and make work.
Title: Re: 917 180 degree V 12
Post by: gerritv on April 11, 2018, 03:09:15 AM
That diagram brings up memories of the Tecalumit Jackson injection system for Mini Cooper engines amongst others.
Title: Re: 917 180 degree V 12
Post by: Roger B on April 11, 2018, 08:38:48 AM
I have had a closer look at the pictures of the injection system used on the 1/4 scale model. It looks to be quite a reasonable solution. For manifold injection the pressures are quite low and the timing is not critical so a simple variable stroke pump can be used rather than the controlled spill system that is required for a diesel.
The pump has two gear driven cam shafts operating rockers that are mounted on a central (probably eccentric) pivot shaft to adjust the stroke. This shaft is coupled to the throttle slides by a bell crank. There are two fuel feed galleries on the outside of the pump with individual inlet valves for each plunger delivery valves are fitted on top of the pump.
At 4.5cc per cylinder a 2mm plunger may be too big. The stroke at full output would be 0.3-0.4mm (plus a bit for leakage past the plunger) so something smaller may have been used.
The design of the injectors is not obvious from the picture. A mushroom valve like Find Hansen uses (and was also used on the Lucas PI system) should work well for manifold injection.
The full size 917 fuel pump used a single camshaft although the plungers were offset. The metering system is not obvious but as the pump was developed from a diesel pump it is probably a helix controlled spill system.
Your 1/3 scale version will have larger cylinders so 2mm plungers should be ok and are not too bad to work with. It may be a challenge to fit all the parts into a prototype size fuel pump  :headscratch: but I think it can be done.
Title: Re: 917 180 degree V 12
Post by: steamer on April 11, 2018, 11:22:49 AM
Thanks for that Rodger!     It sounds wonderful!   I remember my Dad telling me a story about his trip to Detroit Diesel.    He was a Fire Department Master Mechanic with many years experience all the way back to WWII.    He told me that the technician at DD Brought out an injector assembly in a beaker of fuel.   Took it out and showed him how smooth it was, took the piston out put it in ect.   He then held the piston in the palm of his hand for about 5 seconds.   It would no longer fit in the barrel of the pump.    Put the whole thing back into the beaker, and a minute or 2 later,  It slipped right back in......33 millionths clearance or some such number....

OK   I'll keep my eye on it...though I don't mind saying....it terrorfies me to think of trying to tackle something like that...

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on April 11, 2018, 12:14:03 PM
Roger, Dave.

This thread has developed into a very interesting fuel injection sub topic.

As Roger will agree, direct diesel injection is hard enough, requiring precisely controlled squirts of diesel fuel at very high pressures.

Indirect petrol injection can be achieved at much lower pressures but adds yet another control dimension. That is the additional need to maintain precise control of the fuel air mixture. The explosive limits for a petrol (gasoline) air mixture are very narrow (typically  15:1 by weight). The Methanol/ air ratio is somewhat wider. Add some nitro methane and the limits are wider still, almost any mixture will burn.

The petrol injection system required for a road or race car needs to map and control the fuel flow to the mass air flow ratio for all conditions of engine load, engine speed, throttle setting, acceleration, over-run etc. etc. Clearly we are not going to be able to achieve this level of mapping and control at model scale.

It looks like the Schilling injection set up is both simple and actually quite cleaver. It only attempts to match the fuel flow to engine speed at one point on the map. It looks like they set the throttle position, run the engine up to speed with that huge electric motor, then they adjust the bypass valve, by hand, to give the correct fuel flow (pressure) for that one engine speed condition.  In much the same way as we adjust the needle valve on a big model aircraft engine, to set the mixture for wide open throttle running condition.

Et Voila, we demonstrate a running petrol injected model engine on the test bench.

We should therefore think of the Schilling injection system as a big pressurised carburetor (which is just what the translation tells us).

Well, that's my take

Mike   :noidea: :noidea: :noidea:
Title: Re: 917 180 degree V 12
Post by: Roger B on April 11, 2018, 12:23:56 PM
I was surprised at the rev range I was able to get with a fixed injection pump stroke. The speed dependent leakage past the plunger may have had an effect. I am currently refitting the helix controlled fuel injection system to my horizontal engine to repeat the trials from last year when, as I found later, there were other problems with the engine.

http://www.modelenginemaker.com/index.php/topic,7701.0.html
Title: Re: 917 180 degree V 12
Post by: steamer on April 20, 2018, 02:33:44 PM
A little inspiration.....

https://www.youtube.com/watch?v=0QzVs8IBn_E

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on April 28, 2018, 01:32:52 PM
That diagram brings up memories of the Tecalumit Jackson injection system for Mini Cooper engines amongst others.

Interesting read!...
Title: Re: 917 180 degree V 12
Post by: steamer on April 30, 2018, 12:34:37 AM
Actual progress in this area....found some new pictures, and have a lot of design done....nothing to show just yet....still getting the layout and specs but..

25.4 bore
20 stroke
ball bearing crank
split rods
DOHC 2 valve/cylinder   same size
2 rings   1 compression 1 oil....
dry sump
1 oil pump   6 scavenge.
Carbureted....and TBD.
Air cooled....
dual ignition with dual spark plugs...per original   ( 10-40 rimfire plugs)
Lemans era exhaust.....


Its going to be a while before I can start this.....that Wallaby needs to get done and before that happens, I need to heal up....but I'm on a better course...

Probably time to move this thread.....out of Chatterbox...

Title: Re: 917 180 degree V 12
Post by: 90LX_Notch on April 30, 2018, 12:38:32 AM
Don't you have a "Tiny" to finish also?

-Bob
Title: Re: 917 180 degree V 12
Post by: steamer on April 30, 2018, 12:39:12 AM
I need to model up the cam cover on the right side intake to include the injection mount....I found a picture of one..

And a couple of section views...
Title: Re: 917 180 degree V 12
Post by: steamer on April 30, 2018, 12:39:42 AM
Don't you have a "Tiny" to finish also?

-Bob

Yup....Its there for when I need a break from the other two..... 8-)

Title: Re: 917 180 degree V 12
Post by: b.lindsey on April 30, 2018, 12:46:00 AM
24 spark plugs  :o. You gonna make em Dave or go with bought ones?

Bill
Title: Re: 917 180 degree V 12
Post by: steamer on April 30, 2018, 12:49:33 AM
24 spark plugs  :o. You gonna make em Dave or go with bought ones?

Bill

The plan is the 10-40 rimfires    purchased
Title: Re: 917 180 degree V 12
Post by: crueby on April 30, 2018, 12:59:34 AM
Wow. Just, wow.

The 3D model alone is impressive, cannot wait to see it actually made!

 :popcorn:
Title: Re: 917 180 degree V 12
Post by: steamer on April 30, 2018, 01:14:18 AM
Wow. Just, wow.

The 3D model alone is impressive, cannot wait to see it actually made!

 :popcorn:

Well    don't hold your breath.   The last 3 years my life has not been my own   Two start ups, a daughter with cancer and being unable to walk for the last 3 months don't promote productive shop time.   I had a lot of time sitting on my butt...so I drew it up.   It needs to be detailed and some areas aren't designed yet...so it will be a while.     But   I don't care..and last time I checked I was the only one who mattered...so I'll get to it   and I'll publish it here
Title: Re: 917 180 degree V 12
Post by: b.lindsey on April 30, 2018, 01:17:27 AM
Not to mention crew chief for a budding RC racer :)  Let's hope the next three years go better Dave. Just glad things are getting back to normal even if slowly.

Bill
Title: Re: 917 180 degree V 12
Post by: steamer on April 30, 2018, 01:20:33 AM
And im not starting this till i have prints..
Title: Re: 917 180 degree V 12
Post by: steamer on April 30, 2018, 02:35:17 AM
Many thanks to Mike Tull  ( Vixen) for coaxing me to look at a ball bearing crank.   It's a Schilling technique and pretty damn brilliant.   I'll end up with a straight accurate crank with hardened bearing surfaces.   
Title: Re: 917 180 degree V 12
Post by: Vixen on April 30, 2018, 09:06:48 AM
And im not starting this till i have prints..

And I'm not starting mine until I have a copy of the prints.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on April 30, 2018, 05:28:17 PM
And im not starting this till i have prints..

And I'm not starting mine until I have a copy of the prints.

Mike

Ya Damn Skippy you're not!    8-)
Title: Re: 917 180 degree V 12
Post by: steamer on April 30, 2018, 05:34:52 PM
And im not starting this till i have prints..

And I'm not starting mine until I have a copy of the prints.

Mike

And you my friend will be the first to get them!

Title: Re: 917 180 degree V 12
Post by: b.lindsey on May 01, 2018, 01:05:28 AM
Good move Dave, this design/build is in its proper place now  ;) Looking forward to the continuing adventures of your 917 V12.

Bill
Title: Re: 917 180 degree V 12
Post by: steamer on May 01, 2018, 01:37:41 PM
Good move Dave, this design/build is in its proper place now  ;) Looking forward to the continuing adventures of your 917 V12.

Bill

Me too!

Title: Re: 917 180 degree V 12
Post by: Jo on May 01, 2018, 01:43:18 PM
It might be worth adding a link to the first posting to where the actual build begins  ::)

Jo
Title: Re: 917 180 degree V 12
Post by: steamer on May 01, 2018, 03:05:08 PM
Hey Jo
When the build starts I'll start a build thread    this will remain a design/research thread.   
Title: Re: 917 180 degree V 12
Post by: steamer on October 31, 2018, 11:56:35 PM
OK....had to add this one.....WOW!

https://www.facebook.com/melvyn.wankenobi/videos/10157789467265828/

Dave
Title: Re: 917 180 degree V 12
Post by: b.lindsey on November 01, 2018, 12:49:44 AM
Looks like it requires Facebook log in. Bummer, I don't do Facebook .

Bill
Title: Re: 917 180 degree V 12
Post by: ozzie46 on November 01, 2018, 01:30:46 AM
Looks like it requires Facebook log in. Bummer, I don't do Facebook .

Bill

Me neither.

Ron
Title: Re: 917 180 degree V 12
Post by: steamer on November 01, 2018, 10:28:25 AM
Unfortunately, not my video, and It's embedded in FB.      It's a 917 without the body on, on the road dynomometer....with his foot in it
Title: Re: 917 180 degree V 12
Post by: Jasonb on November 03, 2018, 01:52:03 PM
This link came up on ME forum while talking about flat 4 VW engine models, not looked back through the thread to see if it has been posted before

https://www.hemmings.com/blog/2015/10/30/kinetic-sculpture-internal-combustion-style-modeling-the-porsche-904-and-917-engines/
Title: Re: 917 180 degree V 12
Post by: steamer on November 03, 2018, 02:06:02 PM
It's a flat 12....made to kinda look like a 917...but its not.   No cooling fan, and in other photo's   the output is taken off the crank...which is not prototypical for that engine..

but its a nice model!...

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on November 03, 2018, 02:39:06 PM
It's a flat 12....made to kinda look like a 917...but its not. 

but its a nice model!...

Dave

And Sotherbys made a lot of easy commission money (20%?) just for selling them.

Mike
Title: Re: 917 180 degree V 12
Post by: gerritv on November 03, 2018, 02:43:42 PM
I saw/heard that engine run. My father was a member at TSME at the time. Quite an amazing sound.

http://pics.tsme.ca/viewarchive.aspx, enter 917 as a Search criteria will show 5 photos, one of which include Herb.
Title: Re: 917 180 degree V 12
Post by: steamer on December 16, 2018, 05:36:20 PM
Just a little motivation.....for me .....

THIS is the sound of my people!

https://www.youtube.com/watch?v=FkP5Svl16Qg

Dave
Title: Re: 917 180 degree V 12
Post by: Niels Abildgaard on January 09, 2019, 09:46:41 AM
  It's a Schilling technique and pretty damn brilliant.   I'll end up with a straight accurate crank with hardened bearing surfaces.

Where can one see and read how to do it?
I have his book but it is not very informative how to actually machine parts.
Title: Re: 917 180 degree V 12
Post by: michelko on January 09, 2019, 10:00:07 AM

Hi
in my Bugatti build thread you can see some Information About Building a crankshaft

http://www.modelenginemaker.com/index.php/topic,6848.30.html Starting with post # 35

Michael
Title: Re: 917 180 degree V 12
Post by: Niels Abildgaard on January 10, 2019, 09:28:14 AM

Hi
in my Bugatti build thread you can see some Information About Building a crankshaft

http://www.modelenginemaker.com/index.php/topic,6848.30.html Starting with post # 35

Michael

Thank You for the link that made me not the least wiser.
I still do not understand how You get undivided connecting rods on the crankpins.
I want to make a side-by-side two stroke crankshaft with undivided lower conrods.

https://i.imgur.com/kgeUWsJ.jpg
Title: Re: 917 180 degree V 12
Post by: michelko on January 10, 2019, 09:50:52 AM
Thats easy, you have to put the conrods on the Pins before you press the parts together(or whatever conection method you Chose).


On my Bugatti build i have split conrod but the needle bearing are mountet before Pressing the parts together.

Michael
Title: Re: 917 180 degree V 12
Post by: steamer on February 06, 2019, 01:55:47 AM
A little more inspiration.   A mazda rotary roaring down the Mulsanne straight.....It's LOUD!....but its pretty music

https://www.facebook.com/FYRacecars/videos/1948824995216403/?t=6

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on February 06, 2019, 08:25:36 AM
Hi Dave,

Been there, seen it, done it, felt the pain

The Mazda four rotor engine was very fast, reliable and incredibly loud, At trackside, the banshee howl far exceeded the threshold of pain. You could follow that howl all the way round the 13 mile, three and a half mnuit lap.

Mazda won the race outright in 1995, the first and only win by a non reciprocating engine. It was also undoubtably the loudest engine ever to have participated there. With the speed and noise came an appetite for fuel. The Mazda's and the Kudzu derivative, needed to pit stop to refuel more frequently than their competitors and gradually lost ground.

Give me a 917 anyday.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on February 06, 2019, 12:03:26 PM
It's the roar.....the two cars play a different tune, but it's still sweet music!

Dave
Title: Re: 917 180 degree V 12
Post by: sco on February 06, 2019, 12:41:22 PM
I have the BRM V16 as the ringtone on my phone as the sweetest music, the Honda RA271 runs it a close second though :-)

Simon.
Title: Re: 917 180 degree V 12
Post by: steamer on March 30, 2019, 02:23:46 PM
A bit more motivation.....

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

Damn that thing is small!

Dave
Title: Re: 917 180 degree V 12
Post by: michelko on July 15, 2019, 02:26:42 PM
Hi,
yesterday i visited the Porsche Museum in Stuttgart.
There was an cut open 917 engine an some other parts displayed.

maybee you can use the info from the attached pics.

 
Title: Re: 917 180 degree V 12
Post by: michelko on July 15, 2019, 02:27:44 PM
Did you know they made a crank from Titanium?
Title: Re: 917 180 degree V 12
Post by: michelko on July 15, 2019, 02:29:03 PM
 :cartwheel:
Title: Re: 917 180 degree V 12
Post by: michelko on July 15, 2019, 02:30:23 PM
my Little one test driving a GT2 RS
Title: Re: 917 180 degree V 12
Post by: steamer on July 15, 2019, 02:50:28 PM
I do know that.......but my model will not have that
Title: Re: 917 180 degree V 12
Post by: Vixen on July 15, 2019, 03:24:39 PM
Did you notice the two cutouts in each of the crank webs which provide access to the big end journals? This suggests the titanium crankshaft was made as a bolted assembly, probably with Hirth couplings and big end sleeves over the joint.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 15, 2019, 05:44:06 PM
Ive not seen a crank f uo ll size that was built that way but your comments seem sound
Title: Re: 917 180 degree V 12
Post by: Vixen on July 15, 2019, 06:00:09 PM
Hi Dave,

Go back to posts 138 and 139 and you can clearly see the difference between the one piece steel crankshaft and the eight ??? piece bolted titanium crankshaft. I believe the steel crank was for the Le Mans cars and the titanium crankshaft was developed specially for the overpowered CanAm monsters. Porsche aren't telling.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 15, 2019, 08:54:26 PM
You are correct sir!
Title: Re: 917 180 degree V 12
Post by: steamer on August 27, 2019, 03:28:58 AM
Hey Mike......and Rodger B :o

https://www.facebook.com/quarterscalerc/videos/2330614827212838/?t=3


https://www.boulandmotors.com/

Dave


Title: Re: 917 180 degree V 12
Post by: Vixen on August 27, 2019, 12:07:06 PM
What an incredible engine, it sounds perfect.

Not been able to find any more information about Bouland Motors. They appear to be offering the Cosworth for sale but don't give a price or delivery forecast.

If you need to ask the price..... you cannot afford one.

I hope JonC sees this Cosworth engine, it will encourage him with his build of the same engine

Mike.
Title: Re: 917 180 degree V 12
Post by: Roger B on August 27, 2019, 01:57:28 PM
Very nice indeed  8)  8)  8) I am trying to work out from the Cyclon 2V accumulator if it is a glowplug engine  :thinking:
Title: Re: 917 180 degree V 12
Post by: Vixen on August 27, 2019, 02:19:43 PM
You could be right about glow plugs.

The Cosworth DFV distributor is horizontal and located in the bottom of the 'V' at the rear, just above the clutch It was driven from the pulleys at the front of the engine

There is no obvious sign of a distributor in that location on the model

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on August 27, 2019, 05:05:23 PM
Sliding plate induction.....so at first I was wondering about fuel injection, but I don't see a injection pump, and it appears that the fuel barbs are dummies.....but the induction is what got my attention...for the 917 project

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on August 27, 2019, 05:48:05 PM
Yes, those throttle slides and the Lucas injection trumpets are very prominent on both the Cosworth and the Porsche engines. Thay are also big enough to let you hide conventional model carburetors underneath without them being too noticeable. Full fuel injection and dual spark ignition would be nice but glow plugs and simple carbs delivering methanol are  so much more practical.

Keep it simple.............

Mike
Title: Re: 917 180 degree V 12
Post by: Floating around on December 24, 2019, 10:56:23 AM
Hi All,

Just a heads up, over on the PM forum their is a guy (Alfagta) who currently has some parts of this engine, possibly the whole engine he is working on. I have always found him to be very helpful. He may be able to help with specific pictures or measurements.
Title: Re: 917 180 degree V 12
Post by: steamer on December 24, 2019, 12:34:06 PM
Hey Floating!

Thanks for the heads up!.....

 :praise2: :praise2: :praise2: :praise2: :praise2:

Dave
Title: Re: 917 180 degree V 12
Post by: Floating around on December 24, 2019, 01:30:55 PM
Welcome  :)
Title: Re: 917 180 degree V 12
Post by: steamer on July 31, 2020, 11:05:05 PM
As I'm limited on the expenditures at the moment....design work continues....
con
the 917 is progressing.....I've got the gear train nailed down, and the multipiece crank.   I'm considering 12L14 cylinders.....but I'm not convinced yet   split connecting rods with bronze bush running on hardened bushings with ball bearing mains.   I've sorted out the cam lubrication, and I'll have some jets on the con rod big ends which should provide more than enough splash for the pistons and cylinders/ wrist pins. 

Just pretty pictures for now till I'm working again....

Fusion 360...

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on July 31, 2020, 11:09:54 PM
Some more sections
Title: Re: 917 180 degree V 12
Post by: steamer on September 08, 2020, 07:50:05 PM
Going a bit smaller, to fit the mill better, so 1/4 scale instead of 1/3.   This also allows for a full ball bearing crank.....progress!

Working on the timing gear towers ...then the cylinder head

Block is 7.55" long now

Dave
Title: Re: 917 180 degree V 12
Post by: stevehuckss396 on September 08, 2020, 09:46:41 PM
Thats still pretty long. This will be an awesome thread once the chips start flying.
Title: Re: 917 180 degree V 12
Post by: steamer on September 08, 2020, 10:56:25 PM
Thats still pretty long. This will be an awesome thread once the chips start flying.

Yes it will!    I start a new job tomorrow.   It's contract for 4 months.   But it's work!   and it will bring some money in, 90 percent of which will be putting back to replenish the bank account.    But soon.     I'll be creating a plan set for this engine that I can supply to others   That way others can go down the road I did, kinda like your little demon Steve.    I'm trying to make a good looking and prototypical engine, that will be a "runnah".    I'm trying to keep the machining simple, so that others can do it without a lot of 3D carving, or forcing CNC.   

I'll share the rest of the development on this engine here.   When the build starts I'll start a build thread.

Current specification
1/4 scale Porsche 912 engine of 4.9 liter displacement  ( this engine and a couple of variants were used in the Porsche 917K at Lemans in the early 70's)
0.85 bore
0.69  stroke
12 cylinder with a 120 degree crank but dispositioned 180 degrees.
Air cooled via engine driven fan ( like the prototype)
Ball bearing crank and connecting rod bearings
Ball bearing cam bearings
Electronic spark ignition with dual distributors,   Layout TBD.
Modular cam shaft, which makes long cams a lot easier to make.
7.5 to 1 compression with 2 compression rings.   No oil control rings.
True center gear drive to a separate drive shaft out rear of the engine which is keeping with the prototype.
I'll be using DP gears   ( 32 DP and 48 DP).    IF that is a problem, I'll offer an alternative design using MOD gears.
I'll probably detail the parts with dual dimensions  ( English and metric).

Stay tuned.....


Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on September 09, 2020, 12:01:31 AM

..........
I'll share the rest of the development on this engine here.   When the build starts I'll start a build thread.
..........

Stay tuned.....

Dave


Dave

You cannot believe how much I am waiting for you to start making chips.

Good luck for tomorrow and again when the build starts

All tuned in and waiting

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on September 09, 2020, 12:35:37 AM
Lol   Well Mike     me too   for the last couple of years.    Priorities are a changing all the time with my daughter and now recovery, for her and US.     Things will come together....
Title: Re: 917 180 degree V 12
Post by: fumopuc on September 09, 2020, 06:29:11 AM
Hi Dave,
a very interesting project.
Just looking into the catalog of my favorite piston ring supplier, 22x2 mm are available of the shelf.
Looking into you first draft, it look´s like another project for the fast coming time after retirement end of this year.
It is good to know, that you have in mind already, that metric guys like me are able to modify bearings, shaft, bolts and may be the gear train.
On the other side, I have learned with the Snow Engine and Bruce Macbeth Engine also, that to redraw a design in Fusion 360 and to modify there all necessary metric design it not a big issue too.
Gear train will not be a big issue also, because 32 DP and 48 DP should be available in the UK of the shelf and standard Boston Gears gears are available for low freight rate by Amazon.
So I am waiting for your new thread.
Title: Re: 917 180 degree V 12
Post by: Johnmcc69 on September 09, 2020, 05:15:12 PM
 :ThumbsUp:
 Pretty cool Dave! Looking forward to seeing this develop.

 Congrats on the new job!!

 John
Title: Re: 917 180 degree V 12
Post by: b.lindsey on September 09, 2020, 10:13:43 PM
Dave, congrats on the new job as well. Maybe it will turn into more than just a contract, who knows.

Bill
Title: Re: 917 180 degree V 12
Post by: steamer on September 09, 2020, 11:34:44 PM
Fumopuc

I'm trying to use simple design where ever possible.   The gears are primarily spur, though there are some small bevel and crossed helical like the prototype.

I'm still working the lubrication system.  It doesn't need the 5 scavenge pumps that the original had, as the crank will need very little lubrication.   However the cams will need some lubrication, so I'm keeping that in mind as I go.    I think grease packing the cam will be just fine.  Trying to keep it simple.... 

Keeping the prototypical cam drive boxes is proving to not be that hard, and they will be split down the middle like the original.   

Stay tuned!    And thanks for the support!   I start my new contract job today, and my consulting efforts are starting to pay off with more work!!!    Things are going to get crazy...but that's alright.

Dave
 
Title: Re: 917 180 degree V 12
Post by: Art K on September 10, 2020, 03:15:09 AM
Dave,
It is great to see movement on this project. Good luck with the new job!
Art
Title: Re: 917 180 degree V 12
Post by: steamer on September 11, 2020, 01:57:20 AM
Thanks Art!

Good progress tonight!!    Got the cam gears in and sorted out, and I've got the distributor holes sorted out relative to the drive shaft.   Need to source some gears for the distributors.     48DP or so I think will do just fine....

Fine tune both of these features, and then rods and pistons....from there I'll have everything I need to do the cylinder heads and valves, and then oil pump drive...won't be long now I hope....We'll see how crazy work gets.

Dave


Title: Re: 917 180 degree V 12
Post by: steamer on September 11, 2020, 02:13:26 AM
Honing in on it.

Title: Re: 917 180 degree V 12
Post by: crueby on September 11, 2020, 03:31:02 AM
Wow.  That sums it up!    :popcorn: :popcorn: :popcorn:
Title: Re: 917 180 degree V 12
Post by: sco on September 11, 2020, 07:36:09 AM
Wow.  That sums it up!    :popcorn: :popcorn: :popcorn:

Agreed!  Keep at it Dave - enjoying seeing the design come together.

Simon
Title: Re: 917 180 degree V 12
Post by: Jasonb on September 11, 2020, 08:13:40 AM
  Need to source some gears for the distributors.     48DP or so I think will do just fine....

What, DP gears on what would have been a metric engine, that will never do :LittleDevil:

Would MOD0.5 give a good representation at 1/4scale of probably MOD2 gears on the full size thus keeping PCD and tooth count the same? It's also close to 48DP.

Drawings are looking good, just awaiting some swarf production now to be able to see the parts in the flesh.
Title: Re: 917 180 degree V 12
Post by: Jo on September 11, 2020, 09:26:16 AM
What, DP gears on what would have been a metric engine, that will never do :LittleDevil:

Maybe I should mention that the Diametric Pitch of a 0.5 MOD Gear is 2", 1 MOD gear is 1" and a 2 MOD gear is 1/2". So MOD gears are based on fractional imperial measurements but quoted as metric measurements  ::)

Jo
Title: Re: 917 180 degree V 12
Post by: steamer on September 11, 2020, 11:49:23 AM
  Need to source some gears for the distributors.     48DP or so I think will do just fine....

What, DP gears on what would have been a metric engine, that will never do :LittleDevil:

Would MOD0.5 give a good representation at 1/4scale of probably MOD2 gears on the full size thus keeping PCD and tooth count the same? It's also close to 48DP.

Drawings are looking good, just awaiting some swarf production now to be able to see the parts in the flesh.

I understand Jason,   So I brought this glaring omission to the attention of the CEO or Piper Engine works, as obviously that will never do!    He patiently listened to the objection....and then his lip curled, and that familiar throbbing vein in his forehead started to bulge, ......As I extricated myself from his office with haste, I could vividly see some office supplies being hurled, and something about telling that Bloke to kick in the cash for MOD cutters!!!.....I wasn't going to hang around ....if being Friday and all...

Dave
Title: Re: 917 180 degree V 12
Post by: john mills on September 12, 2020, 03:27:46 AM
if the no of teeth fit and the what is the difference in the actual shape of the teeth other than for calculations in
metric or imperial  Dp   OR module  .
              john
Title: Re: 917 180 degree V 12
Post by: Jasonb on September 12, 2020, 07:19:16 AM
if the no of teeth fit and the what is the difference in the actual shape of the teeth other than for calculations in
metric or imperial  Dp   OR module  .
              john

Well this is where Jo's Diametric pitch comes a cropper if you want tooth count and PCD to be the scale.

Assuming the original used MOD gears and lets take an easy 50/100 gear train then at full size of MOD2 we get the following

50T has 100mm PCD, 100T has 200mm PCD. (100+200)/2 gives PCD or Ctr to CTR distance of 150mm. at 1/4 scale we get MOD0.5 and 37.5mm PCD

Now if you use 48DP gears as they are whats easily available locally or you have the cutters on full size of 12DP

50T has 4.167, 100T has PCD of 8.333 ( 4.167+8.333)/2 = 6.250" at 1/4 scale 1.5625"

Now if we convert the 1.5625 to metric we have the gear ctrs at 39.688mm rather than 37.5 so the whole layout of the engine will need to be adjusted or tooth counts altered which you would probably not have to do if MOD gears were used.

That is why I raised the question about what would "give a good representation at 1/4 scale" staying with scale Ctr to Ctr and number of teeth would be a better representation.

As Dave has said he will do a set of drawings with metric gears I thought it may save him some time if MOD were used from the start as it's not just a sheet or two with some different gears but many many parts of the engine that are likely to need altering. having done it with single cylinder engines with just two gears I know how much has to be altered let along on an engine like this. Unless Dave is thinking of making custom cutters to MOD0.5292 ;)
Title: Re: 917 180 degree V 12
Post by: Jo on September 12, 2020, 09:10:24 AM
if the no of teeth fit and the what is the difference in the actual shape of the teeth other than for calculations in
metric or imperial  Dp   OR module  .
              john

John I have attached a comparison of MOD profile and DP for the same "size gear" .

Jo
Title: Re: 917 180 degree V 12
Post by: Jasonb on September 12, 2020, 11:01:37 AM
But where does one buy a 25.4 DP cutter for the option on the right?

Try doing it with the nearest standard DP which is 24. From Dave's mention of 48DP I assume he is sticking with common DP sizes.
Title: Re: 917 180 degree V 12
Post by: steamer on September 12, 2020, 11:11:15 AM
 ::)

I'm sure Cherry will leave a comment soon....

Anyway

DP for now,  MOD later....as I've already stated.

Gears are in,   Next is the cam trays, and the upper and lower drives.     The 917 had a very peculiar layout in that regard.   Power was taken off the center of the crank via a large gear.   It drives two parallel shafts.   A upper shaft, which , through a pair of crossed helical gears, drove a pair of distributors/ magneto's as well as the fuel injection pump.      I've read there was a magneto set up as well, but all the photo's I have found thus far show a separate ignition coil. 

The crank also drove an output shaft to a conventional flywheel clutch arrangement.    This was done to reduce the amplitude of the torsional vibration .   I've found evidence that some of the 917 cranks were made in two pieces and ebeam welded together, and I've also found inconclusive evidence of multi piece cranks with Hirth joints.     That said, the crank on this engine is all ball bearing following the Schilling approach.   

Output shaft will be 3/8"  steel, although the original was titanium, and only 1" (25.4 mm ) in diameter!!    I'm still amazed that they got 620 HP through that shaft....let alone the 917/30  rated engine with twin turbo's that got 1800 HP in qualifying tune!!!

Mentioning that,   The engine I'm working to will be the Lemans version with velocity stacks and probably individual carburation. 

The original engine had dual ignition   (2 spark plugs per cylinder) using the 2 distributors as two separate ignition systems for reliability.   I'll have the 2 distributors, but for the sake of making a reliable runner, I'll leave it as single ignition, and make each distributor fire 6 plugs.

I've finally figured out the ducting for cooling, and it's very simple, and quite clever, and I suspect will be a 3d printed ABS part on the model if I can find the right color plastic to match the fiberglass they used. 

Stay tuned.....I've got some work work to do today...but more CAD tonight and tomorrow I'm sure.

Dave


Title: Re: 917 180 degree V 12
Post by: steamer on September 12, 2020, 11:33:55 AM
if the no of teeth fit and the what is the difference in the actual shape of the teeth other than for calculations in
metric or imperial  Dp   OR module  .
              john

John I have attached a comparison of MOD profile and DP for the same "size gear" (Diametric pitch), the metric teeth are deeper..

Jo

Thanks for that Jo,
Also note that it doesn't affect the OD of the gears.  That's important with the cam drive boxes as there is very little room from gear tip to the shaft..    That said, the Pitch diameter is a good point, but with common cutters, there are going to be differences.

Yes...if I wanted to get the last bit of detail, I'd be making my own cutters to scale DP, what ever that is...and cut the teeth accordingly.   I've not found any good technical references on the subject...so I have to go fish.      but I need to stay will common DP's   32 and 48 are definitely available on the regular market.   32DP can make a "hela strong" gear, even in plastic, so I'm confident we'll have a runner.

The crank is below....

Dave





Title: Re: 917 180 degree V 12
Post by: steamer on September 12, 2020, 11:38:49 AM
if the no of teeth fit and the what is the difference in the actual shape of the teeth other than for calculations in
metric or imperial  Dp   OR module  .
              john

John I have attached a comparison of MOD profile and DP for the same "size gear" (Diametric pitch), the metric teeth are deeper..

Jo

Thanks for that Jo,
Also note that it doesn't affect the OD of the gears.  That's important with the cam drive boxes as there is very little room from gear tip to the shaft..    That said, the Pitch diameter is a good point, but with common cutters, there are going to be differences.

Yes...if I wanted to get the last bit of detail, I'd be making my own cutters to scale DP, what ever that is...and cut the teeth accordingly.   I've not found any good technical references on the subject...so I have to go fish.      but I need to stay will common DP's   32 and 48 are definitely available on the regular market.   32DP can make a "hela strong" gear, even in plastic, so I'm confident we'll have a runner.

The crank is below....

Dave


Actually, the first thing I would do is grab a camera and tape measure and get a ticket to Stuttgart to the Porsche museum so I could count teeth!.....
Title: Re: 917 180 degree V 12
Post by: steamer on September 12, 2020, 11:44:38 AM
Here's a picture of the engine split, showing the shaft layouts.   Output shaft is on the bottom, distributor and cooling fan shaft is above the crank, all driven from the center.

Dave

Title: Re: 917 180 degree V 12
Post by: john mills on September 12, 2020, 12:41:01 PM
interesting  replies  gears are interesting

its good to stick to the standard sizes if you can .if.you can use standard stock sizes that can be the most economical   and if you are cutting which standard cutters in a diving head  they are the standards to use .

if you have hobbing  machine or shopping machine then these sizes can be manipulated to suit the hob will cut a rang of sizes the 25 .4 dp  would be cut with the cutter that covers that size  if  the centre to centre needs to be adjusted you can change the sizes and the hob will generate the correct teeth size to  suit . 
Most of the gears i cut where american stub form  DP   shallower teeth  most were  increased sizes for small numbers  of teeth 5 often with no undercut .stub form gives more compact gears.only cut a few modul form .they were mainly done on a gear shapper .Ionly had one st DP hob a 5DP only used it to do one pair of gears for a machine  the machine drawings specified module form  but only had a 5 DP hob so just altered the sizes and used
that.the shaft centres were fixed.    John   
Title: Re: 917 180 degree V 12
Post by: Dan Rowe on September 12, 2020, 02:03:14 PM
John I have attached a comparison of MOD profile and DP for the same "size gear" (Diametric pitch), the metric teeth are deeper..

Jo, the ONLY thing that is different in the two gears is the clearence, of course this affects the whole depth and the dedendum. The clearance rules vary with different country classification rules.

If you need a 25.4 DP gear use a Mod 1 cutter it has the very same form simply change the clearance.

Cheers Dan
Title: Re: 917 180 degree V 12
Post by: steamer on September 13, 2020, 03:18:04 AM
More progress.....that's enough for today.

3/8 exhaust valve   0.4375 Intake valve, and the prototypical angles...and good thing....you need those angles to make it fit!

Still have some work to do on the heads..in the area of the cooling fins

The gear tower needs a flange all around or it will leak oil.....working it

The gear layout looks really good

I've started to shape the outside and inside of the block....

We have a robust model now.

Dave


Title: Re: 917 180 degree V 12
Post by: stevehuckss396 on September 13, 2020, 10:35:27 AM
Looking good! I read that you changed scale from 1/3 to 1/4. If you think the #10's look too big in the model send me a note and you can return the 10's and I'll send you some 8's.
Title: Re: 917 180 degree V 12
Post by: steamer on September 13, 2020, 01:08:53 PM
Looking good! I read that you changed scale from 1/3 to 1/4. If you think the #10's look too big in the model send me a note and you can return the 10's and I'll send you some 8's.

Thanks Steve.   That's a kind offer!!!     I don't think so....at least not yet.    I need to get the cam drive housing sorted out, and then the cam boxes, which is a redesign from the 1/3 scale...so a bit of work still.   Stay tuned!.....we will see.


Dave
Title: Re: 917 180 degree V 12
Post by: steamer on September 13, 2020, 01:35:16 PM
OK....maybe I answered it already.

Here's a picture of the cylinder head without the valves in.   The upper spark plug hole is .190 or #10 thread OD, while the bottom one is #10 tap drill.

You will notice I'll need to do a small amount of massaging at the corner, this is due to the valve inclination being different for the intake and the exhaust.   However its very small, and will amount to a few swipes with a file...  If I can do a revolve cut on that edge to round the edge over, I can machine it in....I'll look at that a little later.

That said, it looks to me like #10 will work fine.     #8 might be better OUTWARD appearance, but then again...I'm building this as a runner, not shelf queen....I have plenty of time to think about it I suppose..... ::)


Title: Re: 917 180 degree V 12
Post by: steamer on September 13, 2020, 01:42:02 PM
A de featured model of your spark plugs , without the internal proprietary detail, in a step file, would prove invaluable Steve.....Just sayin.... 8)

I need to look at valve lift, and make sure there aren't any collisions, or that I don't set it too deep/shallow....placement is tight...


Here's the real cylinder head...Bore is about 85mm ( 3.34") on the 4.5L...

Dave
Title: Re: 917 180 degree V 12
Post by: stevehuckss396 on September 13, 2020, 02:45:13 PM
I can send an stl file as soon as I get home from work if that will help.
Title: Re: 917 180 degree V 12
Post by: steamer on September 13, 2020, 03:17:41 PM
t
I can send an stl file as soon as I get home from work if that will help.

That'll work!!!

Thanks!!!

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on September 16, 2020, 11:19:09 AM
The grind for this evening will be reducing the bolt circle for the cylinders
Change the bolt pattern in both block halves.
That will let me narrow the cylinders slightly  ( 0.030")
That will let me narrow the cam gear box.
That will let me narrow the gears in the cam gear box.
That will let me add a flange to the cam gear box so it won't leak oil
Then I can start on the Cam box, cams and covers......


........That will be a full evening of work I think......glad, for the moment,   that I'm only cutting pixels!!!....

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on September 19, 2020, 01:34:34 AM
Working from the center out.     Cam profiles....check.   Cam follower.....check.   Valve springs chosen.    check

Lee spring # LC 030D 07 M.

2.5 pounds closed, and approximately 4.4 pounds open.    This compares nicely with a couple of other engine designs I've looked at, and natural frequency is high enough for 9000 rpm operation.    ( sized at 1/13 the natural frequency of the spring)
Valves are .375 exhaust, and .4375 on intake.   Lift is 0.1 for both valves currently. 

Cam shafts are located accurately, and the gear train gear centers are now accurate, and follow fairly closely to prototype. 

I was able to narrow the cylinders, and reduce the bolt circle diameter of the cylinder bolts and that did give me more room.   I'll need to finish that flange effort next, and then I can go all out on the cam boxes.     I am seriously considering a built up cam with hard lobes, and ball bearings in between...but I can be convinced otherwise, but building 24 identical cams and locating them on a main shaft with a fixture seems a good way to go, and I can CNC them to shape easily.

The girl is going to breath...of that I have no doubt.   The intake valve is nearly half the diameter of the cylinder bore!....

Again.....Where ever possible I've tried to keep it to scale.



Title: Re: 917 180 degree V 12
Post by: steamer on September 19, 2020, 01:51:33 AM
and a family portrait....thus far

Title: Re: 917 180 degree V 12
Post by: steamer on September 20, 2020, 03:14:56 AM
A lot of effort today.  Several hours at the PC....but I did crank out a bunch of design on this engine

Here's some shots   I got the cam gear towers finished and split, and a subassembly built.  I have a photo of a real one split as well

I was able to get a good start on the cam box.   There's a lot going on with this part on this engine!..  The model has some obvious manufacturing issues like sharp inside corners.   they'll go away as I refine the model, and cast a weather eye for tool path issues.... but the biggest thing is It will need a tilt fixture for the two valve bank angles.  One is 60, and the intake is 55 If I recall, that's to get that big intake valve in.   so I'll need a fixture to mount this part and the cylinder heads at these angles for machining.    I'll sort that out as I go.   

I've put together a cam shaft assembly.  The intent is to loctite the lobes on a common shaft.  I have 2 bearings on each side of the box for the cams.   Cams are driven from the center, those gears are not on the shafts just yet....They will be though.

I still need to design the valve keepers, and refine the length of the valve stems.   The cam buckets are 7/16" in diameter    There appears to be plenty of room there and that design risk I think is mitigated at the moment.   I intend to use the same keeper design as Ron Colonna used on his Offy.   The valves are about the same size, with the Intake being bigger!.....and the offy is a 1.031" bore...while this engine is 0.846"....

I couldn't resist "Molyhawking" a fan for the engine....it's not what I want, but I wanted the look..... :lolb:  It's about the right size though.

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on September 20, 2020, 03:28:07 AM
Cam drive tower split.

Title: Re: 917 180 degree V 12
Post by: steamer on September 20, 2020, 03:55:41 AM
And a  section....work in progress...but it is progressing!

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on September 20, 2020, 08:07:42 PM
Cylinder head assembly.   I have the follower cups sitting on the stems, though in real life they only located by the cam box.   Copper or Teflon head gasket ring shown, with those big valves.     30 degree valve angle on the Exhaust, and 35 on the Intake.

Title: Re: 917 180 degree V 12
Post by: AlexS on September 21, 2020, 02:21:45 PM
Great designing work Dave!

May I ask how are you assemble or fixing the part build crankshaft and fit the roller bearings?

And I have some "music" to listen for designing some parts in CAD software.

https://www.youtube.com/watch?v=PFUlMUo3h10

Greets Alex
Title: Re: 917 180 degree V 12
Post by: steamer on September 21, 2020, 05:02:40 PM
Hi Alex,    Assembly starts at the middle at the gear, goes out like a string of beads.   It needs an assembly fixture to orient the main bearings in line, but the engine blocks can perform that task.    Individual joints are shaft in socket held with a cap screw and loctite.   ....basically like the shilling V8
Title: Re: 917 180 degree V 12
Post by: steamer on September 22, 2020, 02:02:13 AM
Crank assembly
Title: Re: 917 180 degree V 12
Post by: JonC on September 22, 2020, 09:06:28 AM
Dave,

Some great initial layout drawings and watching this with great interest for my DFV project.

Can I ask what bearing to have based the crank on?

thanks

Jon
Title: Re: 917 180 degree V 12
Post by: steamer on September 22, 2020, 11:09:27 AM
Thanks for the interest Jon,  the crank main bearings are 25 x 32 x 4's 


Dave
Title: Re: 917 180 degree V 12
Post by: JonC on September 22, 2020, 12:37:41 PM
Thanks Dave, keep up the good work.

Just my era this sort of thing.

Jon
Title: Re: 917 180 degree V 12
Post by: steamer on September 22, 2020, 12:48:50 PM
Thanks Dave, keep up the good work.

Just my era this sort of thing.

Jon


Me too!
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on September 22, 2020, 09:38:14 PM
Nice work on the drawings / models Dave  :ThumbsUp:

Do you plan to make the crank webs as one big piece, with all the holes for the pins etc. before you part them into the individual webs, it is assembled from, or make a jig that will ensure that they all are exactly identical ?

Per
Title: Re: 917 180 degree V 12
Post by: steamer on September 22, 2020, 10:50:14 PM
Hi Admiral,

Machine the disks flat and parallel, and then turn the bearing registers.

Actually turn the bearing register, and shoulder, then flip them and mount them in a POT chuck in the lathe and face the opposite side parallel

The center disks are slightly different because they have to bolt to the central gear....that detail isn't there yet, but it will be.

Then take the disks  ( Disk A's  and Disk B's ) and machine the journal pockets and tapped holes all on the mill, and hopefully as exactly alike as I an get them.    The crank throws are machined separate, and loctited and screwed together, in an assembly jig that forces adjacent main bearing diameters to be concentric.   Once its all bolted together and in the engine....it's not going to twist.
Title: Re: 917 180 degree V 12
Post by: steamer on September 22, 2020, 11:00:52 PM
Cam box is starting to come together.   It's amazing how relatively small details really make the model look the part.   If you had told me before that the "egg crate" ribbing on the box would make or break the look,  I wouldn't have believed it.    But it really does make this feature POP...and although I won't be using the through hole acorn nuts, The socket head cap screws  ( M1.6) are going to work holding the cam box to the heads.

I've backed down on spring rates to 1.2 closed, and 2.1 open under advice from Mike Tull  "Vixen".  Thanks for the assist Mike!..

Dave
Title: Re: 917 180 degree V 12
Post by: crueby on September 22, 2020, 11:58:51 PM
Fantastic CAD work - cant wait to see it in metal!
Title: Re: 917 180 degree V 12
Post by: Johnmcc69 on September 23, 2020, 12:32:36 AM
Geez..that's going to be a lot of work. Definitely long term.

 I have the time. :popcorn:

 Real nice work Dave!
 (Hope the new job is going well!)
 :ThumbsUp:
 John
Title: Re: 917 180 degree V 12
Post by: steamer on September 23, 2020, 12:40:24 AM
Thanks Jon,

It's a living!....better than the alternative lifestyle. ::)

My daughter had her last surgery today, to remove her "broviac" which is the plumbing surgically implanted for the infusion of chemotherapy.    She beat it!!   and to prove it, she doesn't need that thing anymore...so she's back to all original equipment specification!   Her physical Therapist is pushing her and she's getting stronger every day......beating cancer twice before you 18 demonstrates how much of a bad ass you are....tough kid.


Here's a family shot up to today.....    Yup needs that egg crate for sure.....

 Dave
Title: Re: 917 180 degree V 12
Post by: steamer on September 23, 2020, 12:47:01 AM
Fantastic CAD work - cant wait to see it in metal!

Well....don't cancel your weekend plans son....it's gonna be a while I think...
Title: Re: 917 180 degree V 12
Post by: Johnmcc69 on September 23, 2020, 01:04:48 AM
Great to hear some good news!
 Of course she's doing well! She's a tough little "Steamer"!
 Keep at it Dave! & blessings to you & the family!

 John
Title: Re: 917 180 degree V 12
Post by: steamer on September 23, 2020, 02:04:17 AM
Well that oughta keep my 440 CNC out of the bars for a few nights.... :lolb:

Roughing passes simulated out to 2.5 hours....there'll be more to finish it....

But I go tool paths!!!....so there's some hope

Title: Re: 917 180 degree V 12
Post by: Art K on September 23, 2020, 03:34:00 AM
Dave,
The 917 flat 12 looks great! I have to say that I've been working on Ron's Offy and have most of it drawn up in Alibre, but you'll have chips before I get to the point of having it shifted to Sprutcam and have machining profiles. I do have a new toy though and will post some photos when I have it set up. Yeah I know that's called the teaser in advertising.
Art
Title: Re: 917 180 degree V 12
Post by: steamer on September 23, 2020, 07:06:11 AM
Looking forward to seeing it Art.....  Always like new toys!

Dave
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on September 23, 2020, 12:27:36 PM
Hi Dave

Thank you for your reply. I should have mentioned that I have Schillings Book, so I know how it's assembled - but great drawing to show all who hasn't seen it.
I hadn't thought of a pot chuck, but it makes very good sense as a 'fixture' that ensures parallelnes. It still doesn't explain the holes that you must 'drill' - will that then be a job for the Rotary Table and the mill, in order to be excatly 120 degrees apart and perfect 90 degrees to the disks ...?

Great CAD work  :ThumbsUp:  and even better news about Ava  :cheers:

Best wishes

Per
Title: Re: 917 180 degree V 12
Post by: Vixen on September 23, 2020, 01:03:54 PM
Hi Dave

 I should have mentioned that I have Schillings Book,

Best wishes

Per

Per,

You are lucky. I've been trying to obtain a copy of that book for years. It's out of print and I have not been able to find a used copy or even find a download.

Mike
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on September 23, 2020, 07:36:34 PM
Mike - I bought it second hand in German 10-15 years ago on eBay.de - a good read with great examples.
Title: Re: 917 180 degree V 12
Post by: Vixen on September 23, 2020, 08:03:54 PM
Per,

A very kind and helpful person sent me a PDF copy. It will be a slow read, I wish I had paid more attention during my German language lessons way back when I was at school. The the drawings need less translation and as you say many great examples.

Mike
Title: Re: 917 180 degree V 12
Post by: JonC on September 24, 2020, 12:46:53 PM
Dave,

I notice that your crank drawing shows the needle rollers for the big end bearing are a pretty snug fit on the width. Did you alter the cylinder stagger to match this or just get lucky with the bearings that were available?

Jon
Title: Re: 917 180 degree V 12
Post by: steamer on September 24, 2020, 01:16:10 PM
I just got lucky on spacing    im not convinced on the needle roller con rod bearing yet either.   
Title: Re: 917 180 degree V 12
Post by: AlexS on September 24, 2020, 06:55:13 PM
Thanks for the explaining and Cad views Dave!
Title: Re: 917 180 degree V 12
Post by: steamer on October 06, 2020, 07:00:43 PM
Much going on with the 917...

Going to set up and run with methanol. or even E85  Easier all around

Wanted to go with 1/4 -32 plugs so I could also do glow plug...but really there just isnt room for them...In their place I am working the 10-40 plug solution.

It's crowded in there......

See below.

Valves are to scale.... 7/16 intake, and 3/8 exhaust on a 0.846 bore........they are manhole cover size!!!!!!...Im going to reduce them a bit, to improve response of the engine

Ignition systems
Spoke with Roy Sholl at CNC engines and I'll be purchasing 2 of his magnum CDI kits    I'll set this up as two 6 cylinder engines using both distributors....

Roy and I had a great conversation and I learned a lot!!!   

For instance, he recommends running the hall switch off the crank if possible, and it keeps it away from the high voltage.    Plenty of opportunity for me to do that so I'll probably go that way with 3 magnets and 2 hall switches....

Dave
Title: Re: 917 180 degree V 12
Post by: Roger B on October 06, 2020, 07:58:31 PM
Unless you are planning to run at a scale Le Mans I suggest that you reduce the valves to around 60-70% of the original size. The bigger the plug you can get in the better the reliability.
Title: Re: 917 180 degree V 12
Post by: Vixen on October 06, 2020, 08:15:54 PM
Echo, echo

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on October 06, 2020, 08:59:43 PM
8mm valves

10-40 plugs

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on October 06, 2020, 09:08:56 PM
Getting better, now you need to find room for a bigger 1/4 x 32 plug, you only need one to run the engine.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on October 06, 2020, 10:10:31 PM
......MAYBE.....


open wide........
Title: Re: 917 180 degree V 12
Post by: steamer on October 12, 2020, 02:11:05 AM
Some progress today....1/4 plugs are in, I have a pair of distributor gears in as well as the hardware to mount the cam boxes. 

Looking for some smaller helical gears....looking for a source.    These are from PIC Design

64 DP   20 and 40 tooth

 A 15 and a 30 would be great!

Dave
Title: Re: 917 180 degree V 12
Post by: crueby on October 12, 2020, 03:40:48 AM
Holey swarf, this an intricate design!  What size are you planning to build it at?  Wow.
Title: Re: 917 180 degree V 12
Post by: steamer on October 12, 2020, 06:02:17 AM
1/4 scale   .846 bore  x .65 stroke
Title: Re: 917 180 degree V 12
Post by: Roger B on October 12, 2020, 05:06:04 PM
Those 1/4" plugs look very deeply recessed. How will you screw them up and connect the HT leads? My Triumph Dolomite Sprint required a special thinwall socket for plug changing and some strange long reach plug caps.
Title: Re: 917 180 degree V 12
Post by: steamer on October 12, 2020, 05:24:28 PM
Thanks for looking in Rodger,  There is enough room.....JUST!!!...... to get a reduced OD socket in...5/16 hex  (8 mm) with a 7/16 socket counter bore...  ( 11.1 mm)   I won't be putting the plugs in with a breaker bar I can assure you!!!....

That is why I was looking at 10-40 plugs so hard....but the value of 1/4-32 is I can get it started on glow plugs as a phase 1 effort, and then mount up sparkplugs later.  Thanks Vixen for staying on my backside and making sure I could do this.   It will help with debug later.

I'll be running it regardless on E85 with a small amount of oil added...as it will run well with either glow plugs or spark plugs and RC carbs in the .15 cu in range don't mind running the E85.


Dave
Title: Re: 917 180 degree V 12
Post by: steamer on October 12, 2020, 06:08:20 PM
A 120 degree connector and a silicone boot should be good for a connection....
Title: Re: 917 180 degree V 12
Post by: steamer on October 21, 2020, 02:20:45 AM
Distributors are done....based on Steve's Demon V8 design....I've added a mesh adjustment bushing and a separate timing clamp.   This way I can remove the distributor without affecting the timing

I'll be finalizing the cam boxes, and cleaning up the block internal design next.   I'll be purchasing a carb to model next  It's starting to come together now....

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on October 21, 2020, 02:34:42 AM
and a bit of inspiration.....
Title: Re: 917 180 degree V 12
Post by: steamer on October 21, 2020, 02:56:54 AM
and maybe a bit of color.....

Title: Re: 917 180 degree V 12
Post by: Johnmcc69 on October 21, 2020, 03:38:47 AM
 :ThumbsUp:
Excellent work Dave!
  :popcorn:
 John
Title: Re: 917 180 degree V 12
Post by: Vixen on October 21, 2020, 11:00:53 AM
Dave,

This is going to be a very interesting and exciting engine build.  :ThumbsUp: :ThumbsUp: :ThumbsUp:

Will be a welcome change from all the other steam engines.

Keep safe

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on October 21, 2020, 02:35:00 PM
Thanks for looking in Mike and John...not quite ready to start yet. But getting close.    Like I said at the beginning    I want prints in front of me first.....patience....
Title: Re: 917 180 degree V 12
Post by: steamer on October 23, 2020, 04:09:50 PM
Not anywhere near done with the design but its coming along nicely
Title: Re: 917 180 degree V 12
Post by: propforward on October 23, 2020, 04:15:11 PM
Exciting - what an engine! I will enjoy watching that get built for sure!
Title: Re: 917 180 degree V 12
Post by: Hugh Currin on October 23, 2020, 04:41:17 PM
I've found that there are enough problems in a project even with good prints at hand. Without good prints those problems become overwhelming. So, good choice.

Does look like a very ambitious project. I hope to look in now and again. Thanks.

Thanks for looking in Mike and John...not quite ready to start yet. But getting close.    Like I said at the beginning    I want prints in front of me first.....patience....
Title: Re: 917 180 degree V 12
Post by: steamer on October 23, 2020, 05:29:57 PM
I've found that there are enough problems in a project even with good prints at hand. Without good prints those problems become overwhelming. So, good choice.

Does look like a very ambitious project. I hope to look in now and again. Thanks.

Thanks for looking in Mike and John...not quite ready to start yet. But getting close.    Like I said at the beginning    I want prints in front of me first.....patience....

YES.....When I'm making parts...I don't like doing the engineering on the fly....I just want a print...with dimensions I need to hit.....

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on October 23, 2020, 07:33:29 PM
Exciting - what an engine! I will enjoy watching that get built for sure!
Isnt it?    Thanks for looking in Stuart...I ordered a pair of carbs that I think will work out well for what I'm doing   

https://www.justengines.co.uk/shop/carburettors/series-3-twin-needle-carburettor-for-10-21-size-engines/?v=7516fd43adaa

I think it's a good start....

Dave
Title: Re: 917 180 degree V 12
Post by: scc on October 24, 2020, 10:45:55 AM
 :popcorn: :popcorn: :popcorn:
Title: Re: 917 180 degree V 12
Post by: steamer on November 18, 2020, 02:50:02 AM
 8)
Title: Re: 917 180 degree V 12
Post by: Vixen on November 18, 2020, 07:21:22 AM
 8)  8) 8) 8) 8) 8) 8) 8)
Title: Re: 917 180 degree V 12
Post by: JonC on November 18, 2020, 10:23:02 AM
Watching with great interest.
Title: Re: 917 180 degree V 12
Post by: AlexS on November 18, 2020, 05:04:54 PM
 :ThumbsUp: :ThumbsUp:
Title: Re: 917 180 degree V 12
Post by: steamer on November 19, 2020, 04:03:45 PM
Watching with great interest.

ME TOO!    ;D
Title: Re: 917 180 degree V 12
Post by: Jo on November 19, 2020, 04:11:12 PM
I hope your CNC isn't an Artist Dave: Mike T has told me all about his and their unique features they like to add   ::)

Keeping my fingers and toes crossed everything comes out right.

Jo

P.S. Are you going to weigh the before and after machining weight?
Title: Re: 917 180 degree V 12
Post by: steamer on November 19, 2020, 04:39:04 PM
The block is coming along   i still have the pumps to do, and the engine end caps.   The blocks wont be too bad, but the cam boxes are 3 hours each of spindle time..   CAM is your friend here Jo.    That big door stop of aliminum is my motivation to GET IT DONE!.   i may be back out of work with the covid lockdown coming so a good thing to keep me out of trouble.    The 32 x 24 x 4 bearings are on order too.
I may weigh before and after to see how accurate the CAM is
Dave
Title: Re: 917 180 degree V 12
Post by: steamer on November 20, 2020, 01:30:48 AM
I hope your CNC isn't an Artist Dave: Mike T has told me all about his and their unique features they like to add   ::)

Keeping my fingers and toes crossed everything comes out right.

Jo

P.S. Are you going to weigh the before and after machining weight?

My machine is a Tormach running pathpilot....not familiar with Artist.
Title: Re: 917 180 degree V 12
Post by: steamer on July 25, 2021, 08:06:18 PM
Camboxes are good....still some area's to clean up...but getting there.
Title: Re: 917 180 degree V 12
Post by: Vixen on July 25, 2021, 09:07:24 PM
Looking good.    :ThumbsUp: :ThumbsUp:

It's always best to sort out the niggley little details before you cut metal, otherwise you can paint yourself into corner.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 25, 2021, 09:07:36 PM
first test piece....
Title: Re: 917 180 degree V 12
Post by: steamer on July 27, 2021, 02:19:25 AM
Nice 24" piece of 1 7/16" 1144SP on the way
Title: Re: 917 180 degree V 12
Post by: crueby on July 27, 2021, 02:21:42 AM
The shop elves and I have our popcorn and our seats....

 :popcornsmall:
Title: Re: 917 180 degree V 12
Post by: steamer on July 27, 2021, 02:27:36 AM
The shop elves and I have our popcorn and our seats....

 :popcornsmall:
Don't get too excited!   I'm making one.....to prove out the process and tooling....I printed a cylinder at work....Beefy!

Dave
Title: Re: 917 180 degree V 12
Post by: petertha on July 27, 2021, 04:01:01 AM
Can't wait to see the prototype. So no liner, just the cylinder barrel, yes?

Maybe you already have the fin groove cutter of choice nailed down, but just an FYI, I had to do a bit of last minute re-design grooving my cylinders with a Nikcole cutter. The cutter system itself is awesome but the insert depth they show is actually to the end of the relief, actually just a bit shy of what I interpreted as DOC. Also because my cylinder is tapered its possible that the tool shank end can get in the way along the fat end of taper, which can further dictate reduced DOC depending on the taper & part orientation. I tried to chamfer a bit off the shank underside in the mill but holy cow, that steel is tough stuff.
http://niko-nikcole.com/wp-content/uploads/sites/6398/2018/03/Minisystems_web_v1d.pdf

Title: Re: 917 180 degree V 12
Post by: Vixen on July 27, 2021, 06:56:59 AM
Although the Nikcole cutter system is excellent, there are other ways to groove cylinder fins, which are not so nail biting, with the added advantage of a greater depth capability than the Nikcole grooving tool.

The cylinders and cylinder heads for my Bristol Mercury engines required several hundreds of fins to be cut. I used a gang of 0.035" slitting saws with 0.030" spacer washers made from shim stock. Dont mess about, plunge the cutters to full depth then slowly rotate the RT. Keep your tool speed on the low side, likewise the feedrate.

You are cutting into solid metal and leaving the delicate fins behind so everything is less nail bitingly tense than with a single point grooving tool.

Perhaps the most important thing is a deluge of coolant to wash away the chips. If you dribble on some coolant it makes a grinding paste from the chips and everything gets very hot very quickly. The only downside to using so much coolant is it sprays everywhere. 'She who must be obeyed' insisted I change cloths in the workshop before coming indoors and then straight into the shower.

I made a total of 20 cylinders for the two Mercury engines all on my first (home made) manual mill.... 19 were usable, As each Mercury engine needed 9, I now have a complete spare cylinder available..

(https://lister-engine.com/coppermine/albums/userpics/10013/CYLINDR1.jpg)

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

(https://lister-engine.com/coppermine/albums/userpics/10013/Head-46small.JPG)


Mike
Title: Re: 917 180 degree V 12
Post by: petertha on July 27, 2021, 07:16:39 AM
Good stuff Mike! With the Nikcole I was pretty much at the limit of what I could achieve for groove/fin thickness. I had the tool on hand for other purposes & that is mostly what dictated their use. Those ganged saws you show look like a much better approach. The end result is much closer to scale look & aside from show they serve a purpose obviously. I'm never sure when I see jewelers saws & slitting saws & maybe there is one more cousin... is there a number of teeth rule of thumb you can suggest relative to a cylinder OD?
Title: Re: 917 180 degree V 12
Post by: Vixen on July 27, 2021, 09:38:15 AM
It was also a case of using what is readily available.

Slitting saws are designed for deep cuts and are relieved (thinner) towards the centre to prevent rubbing. Fewer teeth will give a bigger gullet which may help with chip removal. But lots of coolant is the real answer to chip removal.

Nothing beats a Nikcole insert for cutting piston ring grooves.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on July 27, 2021, 01:17:39 PM
Correct  the cylinder will not have a liner.   I chose the material based on Ron Colonna's Offy which Uses 1144sp.   What you see is the whole thing.   1144spmachines well with sharp tooling, and it had really good strength.
Title: Re: 917 180 degree V 12
Post by: steamer on July 27, 2021, 05:56:34 PM
I can promise you this   ol Samantha Bell is going to get a workout!!

Title: Re: 917 180 degree V 12
Post by: steamer on August 02, 2021, 12:41:10 AM
First prototype cylinder today     DEFINITELY GOING TO NEED THE SAW!.    That is all
Title: Re: 917 180 degree V 12
Post by: steamer on August 02, 2021, 12:49:36 AM
Parting blade didn't like it...but the rest of the process was pretty good.
Title: Re: 917 180 degree V 12
Post by: Vixen on August 02, 2021, 01:20:55 PM
Oh dear, Dave,   :ThumbsDown: :ThumbsDown:

Thats not what you wanted. Parting/ deep grooving free cutting steel is difficult enough, your medium carbon 1144 was always going to be a challenge. The biggest problem comes when the tool starts rubbing instead of cutting and things overheat. Have you tried a razor sharp HSS parting tool?

Mike

Title: Re: 917 180 degree V 12
Post by: steamer on August 03, 2021, 12:51:45 AM
That was a razor sharp hss tool!..   it did not like the two flats at all!  Saw time!
Title: Re: 917 180 degree V 12
Post by: crueby on August 03, 2021, 12:53:49 AM
Interrupted cuts with a parting tool are tough, needs small overhang, a low speed and really close check of tool height.  Or a saw!!
Title: Re: 917 180 degree V 12
Post by: gadabout on August 03, 2021, 01:15:45 AM
Can you machine the flats on after cutting the fins?
Mark
Title: Re: 917 180 degree V 12
Post by: steamer on August 03, 2021, 01:26:49 AM
Can you machine the flats on after cutting the fins?
Mark

MAYBE.   But I don't want to    1.0 mm tool 5mm deep in 1144 doesn't make me.feel all warm and fuzzy....X7....x12....
Title: Re: 917 180 degree V 12
Post by: steamer on August 03, 2021, 01:42:49 AM
Interrupted cuts with a parting tool are tough, needs small overhang, a low speed and really close check of tool height.  Or a saw!!

BARE minimum overhang, and slow.....at 5mm....it was getting sketchy....NOPE....   I'll do some programing.....
Title: Re: 917 180 degree V 12
Post by: crueby on August 03, 2021, 03:00:20 AM
Dang, just looked closer at the plan picture, I didn't realize that it was that small! 
Title: Re: 917 180 degree V 12
Post by: steamer on August 03, 2021, 03:24:45 AM
iF you wanted to make some funky barrel cam....this was the tool to do it!.....Samantha bell has cut all kinds of slots, cut off 2 inch stock...ect....that sharp little parting tool was doing the hula!.....no matter...just ordered 3 carbide slitting saws.   I'll make up an arbor and we'll keep moving.     Now the good news is....the bore was cut .002" undersize.....per my discretion, and will clean up with a lap nicely.

I need to make a fixture for final boring, and some soft jaws for the mill, but we're moving.
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on August 03, 2021, 11:14:21 AM
No matter what - I'm sure you will end up with a nice runner - but no bets on how long it will take you ....

Pulling up a chair and  :popcorn:   :cheers:

Per
Title: Re: 917 180 degree V 12
Post by: steamer on August 04, 2021, 12:04:25 AM
Thanks admiral!
Title: Re: 917 180 degree V 12
Post by: steamer on August 14, 2021, 11:33:23 PM
Ok great progress today.  I'm still waiting on my saws...so no machining, but I'm nearly done with drive line.   New improved crank, resized bearings ( much more appropriately sized)    and a compression ratio check showing we're at 8.48 to 1 currently

8mm crank pin journals
5 mm wrist pin

Now we're moving here

Dave

Title: Re: 917 180 degree V 12
Post by: steamer on August 14, 2021, 11:45:24 PM
A few other items I was working on today...and perhaps into tonight...  Con rod and bearings   and crankshaft assembly

the Crankshaft is ball bearing mains with plain bearing rod bearings.   Crank case pressure spray lubed with dry sump  Oil pumps off the front.

Con rods are 7075 T6 with a bronze split big end with oil grooves and reamed big end bearing on the aluminum.

Big end bronze has oil groove design from a 240 cc splash lubed 2 cylinder 4 stroke , so should be a good one.
Title: Re: 917 180 degree V 12
Post by: Kim on August 14, 2021, 11:57:31 PM
You're making a lot of progress on this Dave.

In that last picture of the rod - what are the diagonal lines cut in the bearing for?  Are they for oil distribution?

Thanks,
Kim
Title: Re: 917 180 degree V 12
Post by: steamer on August 15, 2021, 12:15:40 AM
Yes.    I've been doing some research on con rods used in the RC industry.    A large portion of even the most extreme application engines  ( 3.3 HP at 41000 rpm out of a 0.21 buggy engine for instance) are bronze bearing with mixed fuel/oil.   Either 2 cycle or 4 cycle.   On the OS 240  ( 24cc....BIG twin) 33mm bore 27 mm stoke.    "Mist lubed"   or fuel blow by lubed one with a bronze con rod.   The big end has this grooving with a cross groove to spread the oil coming in from the bottom hole.   Mid span it has axial grooves for lubing the sides of the bearing, and The top end just has the central groove .    CNC makes this really easy.....

I am considering putting these features directly into the rod, and dispense with a bearing shell, but as this is an experimental, I'll keep the bearing.    Journals are dead hard dowel pins  ( 52 Rc) so they should outlive me.

Dave
Title: Re: 917 180 degree V 12
Post by: dieselpilot on August 15, 2021, 01:02:11 AM
What is the angled groove for? This isn't in the OS rod. I never understood the hole in the high pressure area.
Title: Re: 917 180 degree V 12
Post by: Johnmcc69 on August 15, 2021, 01:05:31 AM
 :ThumbsUp:
 Pretty cool stuff Dave! Looks like you've done a lot of research.
 You really have to appreciate 3D CAD for projects like this. (Not that there's anything wrong with any other way...)

  :popcorn:

 John
Title: Re: 917 180 degree V 12
Post by: steamer on August 15, 2021, 01:17:57 AM
What is the angled groove for? This isn't in the OS rod. I never understood the hole in the high pressure area.

Actually   It is.  I left a picture of the os rod in the post  The hole at the bottom of the rod  , On the cap....is actually the low pressure area.

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 15, 2021, 01:47:42 AM
Angled oil grooves are put in bearings to spread the oil over the width of the bearing.   You will find them in engines, machine tools and many other places...

Here's some examples
Title: Re: 917 180 degree V 12
Post by: Kim on August 15, 2021, 05:31:59 AM
That's fascinating...
And that last picture makes my eyes go crossed!  :insane:

Kim
Title: Re: 917 180 degree V 12
Post by: stevehuckss396 on August 15, 2021, 11:52:20 AM
you have done a mountain of work already. Are you about ready to move forward and start making machined parts?
Title: Re: 917 180 degree V 12
Post by: steamer on August 15, 2021, 01:54:53 PM
Thanks for looking in Steve. Kim, Crueby and diesel!   

Well Bubba...what do you think...would you start?   8)   

My answer....well   Nearly
Still open issues

Taking one plug out of the heads.   It creates a great deal of variation in the compression ratio....so with 1/4-28's   1 plug per cylinder it is instead of the prototypical 2 per cylinder like it has now.   I'm going to take out the exhaust side plug so that I can put in more cooling fins and open the air flow up.  It looks constricted to me....I'd rather have an engine that I need to reduce the cooling than go looking for it!

The oil pump.  I want one.  I don't want one buried in the case such that I have to split the case to get to it like the real one.   So I'll have an oil pump and perhaps a scavenge pump, but down low, external and driven off the front of the engine.     Oil pumps job on this engine is to create a mist in the crank case.  Lube tank is external, and i'll probably recirculate with one or both pumps.   But for me, burying the pumps in the case and driving them with ity bity spur gears at 8000 rpm sounds like a bad idea....at least at 1/4 scale.

I also want to take what I've learned thus far and do a redesign on the cases.   I can simplify them and make them more straight forward to make.   Currently they are suffering a lot of CAD fixes, and the models are somewhat of a mess.   Actually, this should be pretty straight forward, as I think I know what I want.

.....Close?.....whatchathink Bubba?

Dave






 
Title: Re: 917 180 degree V 12
Post by: stevehuckss396 on August 15, 2021, 03:21:13 PM
I think you sound unsure so I think you should wait. If you havent decided on the crankcase yet then you cant even start. That is my first part when I build. Then I typically make the heads and oil pan. Being unsure of the head design and oil pump drive you cant do heads or crankshaft. I think you should wait until you have the entire engine in cad and you are happy with it. 
Title: Re: 917 180 degree V 12
Post by: dieselpilot on August 15, 2021, 03:39:06 PM
In the photo you have that is not a groove, but some optical artifact. You can see the axial groove meeting the chamfer, but not the artifact. Here's a better photo.

I'm aware of these sorts of grooves. In all cases the grooves do not break through to the side of the bearing. You want to keep oil within the bearing surface.

The hole in the cap is normal. The one I question is the hole where it meets the beam, that is visible in the stock photo. Most hobby engines don't have a hole there, but some do. I have a hard time with the concept, but maybe the dynamics of the loads means it does help one way or another. I've never seen much talk about it.

In any case, I doubt the rod bearing will be critical. Are you still planning fasteners for crank rod journals?
Title: Re: 917 180 degree V 12
Post by: steamer on August 16, 2021, 02:30:09 AM
The most critical surface on a 4 stroke is the top surface closest to the piston.    I'll leave the grooves in including the spiral one as a way to spread the oil on the bearing from the bottom and feeding towards the top during rotation.   The conrod has 2 M3 screws, and that should be sufficient with hard journals.     The latest RC 1/8 scale buggy engines use just a simple unadorned busing 1 hole..at .21 cu in, producing 3.3 HP at 44000 rpm on nitro fuel getting the ever loving snot beat out of them for literally over an hour at a time.  I think my little journals fed by a fog of oil from a pump....something the commercial units don't do...should be just fine....

Dave
Title: Re: 917 180 degree V 12
Post by: Roger B on August 16, 2021, 05:07:21 PM
Looking good  :)  :)  :wine1: I'm looking forward to the cutting of the fins  :ThumbsUp:  :ThumbsUp:

My 12cc twin has 8mm mains and 5mm little ends. The little ends have bronze bushes and the big ends split bearings. I have used 4 off M2 fastenings due to my packaging requirements. I haven't used any oil grooves. I ran the engine for a while with the 180° crankshaft including a series of load tests and when I stripped it down to fit the 360° crank everything looked OK. It is semi splash lubricated (at least that is the theory  ::) ) It revs out to around 9000rpm. I have attached my electronic back of an envelope sketch of the conrods.
Title: Re: 917 180 degree V 12
Post by: steamer on August 17, 2021, 02:43:02 AM
Thank you Roger!  Much appreciated!

What is/was the compression ratio of this engine?
What fuel does it run on?

Dave
Title: Re: 917 180 degree V 12
Post by: Roger B on August 17, 2021, 11:08:06 AM
The compression ratio is around 8-1. At this size the volume of the sparkplug and the valve heads is significant. It runs on Alkylate (Coleman?) fuel as that smells less than normal petrol (gasoline).
Currently I am using it to develop a petrol injection and slide throttle system ready for when your 917 is finished  :) :stir: :wine1:
Title: Re: 917 180 degree V 12
Post by: steamer on August 17, 2021, 02:40:45 PM
 :lolb:...Race ya!
Title: Re: 917 180 degree V 12
Post by: AlexS on August 18, 2021, 05:44:26 PM
Lovely engineering!

How can one make that cross oil grooves on the bigend bearings in a conventional way not cnc?

May I ask what kind of cnc do you have to brew this engine?!
Title: Re: 917 180 degree V 12
Post by: Dave Otto on August 18, 2021, 06:04:50 PM
How can one make that cross oil grooves on the bigend bearings in a conventional way not cnc?

Here is one way.

https://www.youtube.com/watch?v=lHBX-aboZsU

Title: Re: 917 180 degree V 12
Post by: crueby on August 18, 2021, 06:48:27 PM
Now that is clever! Just love a purely mechanical linkage for making something.
Title: Re: 917 180 degree V 12
Post by: Kim on August 19, 2021, 12:09:42 AM
Wow... that's mesmerizing!
It's a lot like cutting a VERY corse internal thread, isn't it?  It's like 1-TPI or something?  With a different thread shape, of course.

Kim
Title: Re: 917 180 degree V 12
Post by: dieselpilot on August 19, 2021, 03:04:13 AM
Youtube has some videos of dedicated lathes for this process. Some people would just do it at 20 RPM hand feeding in one pass. Even CNC lathes can have a hard time if the spindle speed can't be set low enough or the feed rates aren't high enough.
Title: Re: 917 180 degree V 12
Post by: steamer on August 19, 2021, 05:34:37 PM
Lovely engineering!

How can one make that cross oil grooves on the bigend bearings in a conventional way not cnc?

May I ask what kind of cnc do you have to brew this engine?!

Tormach 440pcnc
Title: Re: 917 180 degree V 12
Post by: steamer on August 19, 2021, 05:38:47 PM
1 tpi is what is modeled.
Title: Re: 917 180 degree V 12
Post by: steamer on August 19, 2021, 05:40:29 PM
In reality...you could just carve it in with a mototool
Title: Re: 917 180 degree V 12
Post by: steamer on August 20, 2021, 12:57:17 AM
Actually there is a very straight forward, albeit tedious, method to cut that groove without a cnc mill, or a funky lathe fixture...though that is a cool fixture.

Just plot points!!!

It would be in the x, the y and the z ...BUT completely doable.   Spool up a ball end mill and keep the spacing small, and it could be done...yes Tedious...but doable.

Honestly,  I would just use the dremel...

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 20, 2021, 01:08:18 AM
The next method, of slightly more complication, but doable for most, is to mount the bearing in a indexing head, and plot points in the XY only, with a angular offset between each point.  It would require a fixture to hang on to the bearing, but again...no magic....just work.

Title: Re: 917 180 degree V 12
Post by: Vixen on August 21, 2021, 01:46:18 PM
Yes.    I've been doing some research on con rods used in the RC industry.    A large portion of even the most extreme application engines  ( 3.3 HP at 41000 rpm out of a 0.21 buggy engine for instance) are bronze bearing with mixed fuel/oil.   Either 2 cycle or 4 cycle.   On the OS 240  ( 24cc....BIG twin) 33mm bore 27 mm stoke.    "Mist lubed"   or fuel blow by lubed one with a bronze con rod.   The big end has this grooving with a cross groove to spread the oil coming in from the bottom hole.   Mid span it has axial grooves for lubing the sides of the bearing, and The top end just has the central groove .    CNC makes this really easy.....

I am considering putting these features directly into the rod, and dispense with a bearing shell, but as this is an experimental, I'll keep the bearing.    Journals are dead hard dowel pins  ( 52 Rc) so they should outlive me.

Dave

There are other ways to ensure a good spread of oil across the full width of the big end (and little end) con rod bearing.

Bristol's machined  full width slots on the big end, little end and cam ring bearings on the 850 HP at 2,300 RPM Bristol Mercury engine, These bearings were pressure fed.

Below you can see one of the two oil grooves machined either side of the big end journal for the master conrod There is a similar groove for lubricating the cam ring just ahead of the front main bearing.
(https://lister-engine.com/coppermine/albums/userpics/10013/P1040024small.JPG)


This shows the oil groove in the slave rod big end bearing. In the foreground is the 'floating' bronze bush for the master conrod.
(https://lister-engine.com/coppermine/albums/userpics/10013/P026small~0.JPG)


In my collection, I have this conrod from a 3 cylinder, two-stroke Kenny Roberts KR3 500cc Grand Prix race bike. 180HP at 12,200 RPM; Oil mist lubricated.

You will notice there are five groves on either side of the big end bearing as well the two saw cut slits, all to encourage the oil mist to enter the bearings.
(https://lister-engine.com/coppermine/albums/userpics/10013/IMG_0363small.JPG)

(https://lister-engine.com/coppermine/albums/userpics/10013/P1080370small~0.JPG)


There are more than one ways to skin a cat

Mike

Title: Re: 917 180 degree V 12
Post by: steamer on August 21, 2021, 01:57:15 PM
The groove in the crank pin is a new one on me!   I've seen most of the 2 stroke techniques....including the half holes on the "cheeks"

I've tried very hard to get the roller bearings in for the crankpins....but to no avail....there's just not enough room, unless I reduce the crankpin diameter...and I don't want to go there.....so plain bearing crankpins it is

Oil Pumps....Now we've spoke about the desire to NOT bury an oil pump into the block where the only way in was a complete disassembly of the engine!....so I'll be "blending" the pressure and scavenge pumps into the front of the engine driven either off the front of the crank, or the front of the output shaft brought all the way forward, but OUTSIDE the engine...where I can get to it.

Have I mentioned I love talking about this with you all?....   8)

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 21, 2021, 04:57:44 PM
Some counter weights added....I'll need to size them...so they'll probably get smaller

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on August 21, 2021, 05:51:28 PM
Ah!! Another built-up crankshaft according to the teachings of Schilling.   :ThumbsUp: :ThumbsUp: :ThumbsUp:

Sure makes for a long, thin, whippy crankshaft having six throws and twelve cylinders.

You can see the logic of taking the power out by those gears in the centre, to minimise the whip.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on August 21, 2021, 06:21:00 PM
And the wisdom of  friend who suggested it was a good idea!.
I will spend some time with the good book of schilling regarding balance weight.   From what I can figure   he balanced each throw independently.    100% of the rotating and 60% of the reciprocating..   I should be at least close...I'll let the cad do the math.

Title: Re: 917 180 degree V 12
Post by: Rick Doane on August 21, 2021, 07:09:16 PM
Hello Mike.  That is an interesting rod shape for the Grand Prix cycles.  Below is one of the rods we use in .45 cubic inch (7.5 cc) two-stroke engines that have an RPM range of 25,000 to 28,000.  The similarities are astonishing.  These engines use full complement, uncaged needle bearings (17 for this rod) that are held in by the crankshaft on one side and by the drum rotor on the other.  It is extremely important that the rod runs in the center of the bore.  First photo.
 
The second photograph below shows a small file mark added to both sides to the upper rod bearing, that prevents what we call a meniscus oil ring forming thus preventing oil from circulating well through the top of the rod bearing.
 
In the third photo, I tried to show these two rods that are different, in that the top one is not chromed inside the large end but the bottom one is.  It may not show very well in this shot.  Also, the crank pin is chromed.  This rod design is used in engines from the .21 cubic inch (3.5 cc) to the 1.01 cubic inch (16.5 cc) engines.  If you would like, I can post photographs of rods/needles that were misaligned by only .010 inch (.254 mm) front to back.  The needles actually welded to the rod.

Mr. Steamer, this type of rod may be an option for you.  The 1.0 cubic inch engines also run at ~23,000 RPM range.

Regards…Rick
Title: Re: 917 180 degree V 12
Post by: Vixen on August 21, 2021, 07:41:21 PM
Hello Rick,

I guess the two file marks encourages the oil mist to migrate across the whole bearing width, rather than being 'stuck' to the edges by the meniscus. Funny stuff is oil.

Mike
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on August 21, 2021, 09:01:28 PM
Very interesting rods, bearings and cranks  :ThumbsUp:

Dave, my first thought was quite a bit off counterweight .... followed by - hmm, it might be a very good thing to have more threads for (I know that it's one one per bolt - but) each bolt to hold onto, in order to keep the halves together.

Mike - wherever did you get your hands on one of those rarities ?   :o I would have thought it as 'Pure UnopTainium' ....  :headscratch:

Rick - how come the needles aren't caged - isn't that a major problem area ?... as in more friction and risk of destroying the bearing ...?...  :thinking:

Per
Title: Re: 917 180 degree V 12
Post by: Vixen on August 21, 2021, 10:03:19 PM
Hello Per,

The Kenny Roberts KR3 three cylinder two stroke Grand Prix engine was manufactured for TWR by my friends at Crosthwaite and Gardner. C+G are better know for their historic replica Bugatti, Auto Union and Mercedes Benz engines and cars. They also have an excellent reputation for the manufacture modern race engines and gearboxes.

A few years ago, C+G ran a Christmas Quiz over the internet. Many of the quiz questions were about their historic machines, which suited my knowledge perfectly. I won the top prize, which was an unused KR3 conrod; which had laid in a shelf in their stores for years. I think the quiz was meant to be won by one of their very wealthy customers rather than by an impoverished enthusiast.

Want to make me an offer?

Mike
Title: Re: 917 180 degree V 12
Post by: Rick Doane on August 21, 2021, 11:00:29 PM
Hello Mike and Per:

Mike…..Yes is the short answer.  The only way I can tell is the tale-tale marks on the wrist pin and wear on the bushing.  Prior to this “notch”, I use to get some undesirable markings.  After the release on the edge, there have been no marks at all unless the bottom end was misaligned.  The upper end of the rod gets oiled by the downward stroke of the piston to pressurize the crankcase. It is a fuel rich environment.

Per…..The cages are not important. The photos below show the arrangement of the needles and are held in by the crankshaft and the intake rotor.  If you picture how the rod rotates the crankshaft, there is only a small area on the crank pin that actually contacts the inside of the rod through the rotation.  The needle bearings spread that load over a larger area, reducing friction.  Now, if the crankshaft was not exactly in the center of the bore of the liner/cylinder, you would be able to see striations on the crank pin.  By this, I mean a wear pattern on the crank pin that is at an angle to the rotation.

Regards.....Rick
Title: Re: 917 180 degree V 12
Post by: steamer on August 21, 2021, 11:03:59 PM
Very interesting rods, bearings and cranks  :ThumbsUp:

Dave, my first thought was quite a bit off counterweight .... followed by - hmm, it might be a very good thing to have more threads for (I know that it's one one per bolt - but) each bolt to hold onto, in order to keep the halves together.



Per
Hey Per
There are 3 m3 cap screws in each cheek half, with integral counterweights.  Thus far they are as large as I could make them...I'm hoping they are too large at this point, and I'll need to cut them back a bit...but we'll see!

Thanks for the photo's Rick!  I'll look at those carefully!

I'm in car with the Corvettes.....lovely sound....


Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 21, 2021, 11:09:42 PM
Rick...What is the rod material?  and is it hardened?

Dave
Title: Re: 917 180 degree V 12
Post by: Rick Doane on August 21, 2021, 11:15:58 PM
Hello Dave:

The rod is steel and has been copper washed or coated due to the fact that the fuel has methanol in it.  I do not know if it has been hardened.

Regards.....Rick
Title: Re: 917 180 degree V 12
Post by: Rick Doane on August 21, 2021, 11:22:32 PM
Dave...Thinking a little more, I do not believe the rods have been hardened.  They tend to bend rather than break when introduced to water..... depending on the volume introduced. :ShakeHead:

 
Title: Re: 917 180 degree V 12
Post by: Johnmcc69 on August 22, 2021, 12:14:15 AM
 Great thread & input. Sorry I'm slow catching up, but couldn't the helical slot in the bearings be thread milled? (CNC, using a single point radius tool...)??

 John
Title: Re: 917 180 degree V 12
Post by: steamer on August 22, 2021, 12:29:54 AM
Great thread & input. Sorry I'm slow catching up, but couldn't the helical slot in the bearings be thread milled? (CNC, using a single point radius tool...)??

 John

Yuuuup!
Title: Re: 917 180 degree V 12
Post by: steamer on August 22, 2021, 01:05:17 AM
Looking it over.   Im going to stay with bronze shells ...just as they are.    I can machine those.  Not so sure about the needle bearing solution.    So Im going to go with what I know.

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 22, 2021, 08:21:54 PM
OK it's starting to pull together!    one half of the block, I've sorted out the oil system.   Pumps on the end, feed pump to at tube down that long hole with spray nozzles aimed at the conrod big ends, and drain from the second scavenge pump back out, probably with a large internal tube, or big drilled hole and strainers in the  sumps....like the prototype...
I'll need to put in some more block bolts top and bottom to seal the two halves together.    I'm actually thinking of pulling a aero solution and putting a single thread of silk at the block joint set in shellac as a block seal.   Works on full size planes!

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on August 22, 2021, 08:56:28 PM
Well the two halves will need to go metal to metal because of the bearings. So any kind of gasket, even thin PTFE is out of the question. A single silk thread sounds like a good plan but these days I think they wet the silk with RTV silicone rather than shellac.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on August 22, 2021, 09:54:09 PM
Well the two halves will need to go metal to metal because of the bearings. So any kind of gasket, even thin PTFE is out of the question. A single silk thread sounds like a good plan but these days I think they wet the silk with RTV silicone rather than shellac.

Mike

I am sure there will be some experimentation...but I am serious....that is how the Lycoming's are put together during a rebuild

Skip to 4:37....
 https://www.youtube.com/watch?v=n-26eqLc4pQ
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on August 22, 2021, 10:26:37 PM
Quote
Want to make me an offer?

Nah - I can't afford, nor do I have the rest of the engine .... a 'Racing Collector' in New Zealand do - Kenny Roberts sold him all he had - in exchange for the option of being allowed to race it whenever he wants to.
It is now back into running condition and has been 'raced' down under  :cartwheel:  ohh and by the way - it was raced by Jeremy McWilliams back in 2001. He sat a track record on Phillip Island => it will always be the fastest Two-Stroke 500cc.

Thank you for the explanation and pictures Rick  :cheers:

Looking forward to follow this build Dave  :popcorn:    :cheers:
Title: Re: 917 180 degree V 12
Post by: Dave Otto on August 22, 2021, 11:51:31 PM
We used to assemble air cooled VWs with silk thread and Gasgacinch, but the later ones that I did before getting out of building engines I use the Loctite 518 which always worked great.
Still have that spool of thread in my tool box. :lolb:

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 23, 2021, 12:03:39 AM
518 heh?     Thanks Dave!   Duly noted!     518 with the silk thread or without?

Dave
Title: Re: 917 180 degree V 12
Post by: Dave Otto on August 23, 2021, 12:29:29 AM
Without, the silk thread is an old aircraft thing, not sure it even does any good?

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 23, 2021, 01:23:04 AM
Then that's the way we're doing it!   Thanks Dave!!!

Dave
Title: Re: 917 180 degree V 12
Post by: Rick Doane on August 23, 2021, 02:50:46 AM
You are welcome Per.
Title: Re: 917 180 degree V 12
Post by: steamer on August 25, 2021, 04:57:25 PM
OK    NOT keeping with the prototype, I DID add a pair of pumps on the front of the engine, they are going to be modular, and are back ups going forward....under the heading  "Id rather be looking at it, than looking for it"

As they are modular, I can remove one, or both, and not have to take the engine apart to do so.   The prototype had 3 stacked pumps in the sump, 1 pressure pump, and 2 scavenge, and the only access to them was a full disassembly and split the case.   This one is going to be driven by an Oldham coupling from the output shaft, and can be removed in its entirety if blow by proves adequate...

Now to begin!......The first section is.     Rotating assembly!     I'll build the crank first....and then I can get over being a scardy cat with that saw for the cylinders  ( programing that has got me nervous)

The crank/conrods should be fairly straight forward, albeit requiring careful work.    But thats floating my boat at the moment.

I'll get going and then start the build thread.  The rest we'll figure out as we go.

You can leave the stop watches in your pocket....I'll be building this for the fun of it...it gets done when it's done

Dave
Title: Re: 917 180 degree V 12
Post by: Johnmcc69 on August 25, 2021, 09:52:12 PM
'Letter rip Dave. I got time. (...I hope)

 John
Title: Re: 917 180 degree V 12
Post by: steamer on August 25, 2021, 10:29:27 PM
Just dropped dime at Mcmaster Carr.

Material for the crank and the rods is on the way.....I'll need a #2 and #4 32DP gear cutter  ( 14 1/2 degree) gear cutters....but I have a lot to do before I need those.

It begins!!!
Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 26, 2021, 01:10:32 PM
Thanks John....
Title: Re: 917 180 degree V 12
Post by: steamer on August 26, 2021, 05:31:13 PM
Most of my stock is here!   Way to go Mcmaster!
Title: Re: 917 180 degree V 12
Post by: Vixen on August 26, 2021, 06:02:50 PM
Hi Dave,

 :Director: Let go the breaks and let her rip  :Director:

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on August 26, 2021, 06:07:59 PM
Who needs brakes?.....
Title: Re: 917 180 degree V 12
Post by: Vixen on August 26, 2021, 06:19:33 PM
Who needs brakes?.....

(https://lister-engine.com/coppermine/albums/userpics/10013/how_were_the_brakessmall.JPG)

Way to go Dave.

Mike

Title: Re: 917 180 degree V 12
Post by: Vixen on August 26, 2021, 06:40:35 PM
Hello Dave,

What are you doing about the balance weights for the crankshaft?

I follow the Bristol crankshaft balancing strategy of the balance weights being equal to half (50%) the reciprocating mass plus the whole of the rotating mass. Fairly straightforward, measure some weights, do some maths, determine the size of the balance weights. The effective weight of either end of the connecting rod was measured accurately by suspending a rod horizontally between two precision scales. In this way, the effective weight of the big and little ends could be determined. The weight of the little end is added to the piston plus rings etc, to determine the reciprocating mass. The weight of the big end would be added to crankpin etc to determine the rotating mass.

What have you got in mind?

MIke
Title: Re: 917 180 degree V 12
Post by: steamer on August 26, 2021, 06:52:20 PM
Yes that was from my PM to you.  I am going by the same formula.    There's a lot of weight moving around.   I'll get close anyway.

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 28, 2021, 01:11:18 AM
"A" Crank web "A" side   6 plus 2 set ups, first lathe op.

It's a start

Title: Re: 917 180 degree V 12
Post by: Roger B on August 28, 2021, 11:46:28 AM
There are some quite nice pictures of the insides of a couple of 917 engines on here and the linked page:

https://canepa.com/porsche-917-30-engine-build-up/
Title: Re: 917 180 degree V 12
Post by: steamer on August 28, 2021, 12:52:10 PM
There are some quite nice pictures of the insides of a couple of 917 engines on here and the linked page:

https://canepa.com/porsche-917-30-engine-build-up/

You can see the 3 pumps in the first photo

Dave
Title: Re: 917 180 degree V 12
Post by: Roger B on August 28, 2021, 05:53:40 PM
I was looking for more information on the 917 fuel injection pump and came across those.

I was wondering how the two sets of pump elements were offset. It seems there is one fuel rack in the middle so you need elements with left and right hand helixes and the cams are adjusted to allow for the offset. I found an exploded diagram of a 911 6 cylinder pump. Looks fun  ::)  :headscratch:  :wine1:
Title: Re: 917 180 degree V 12
Post by: stevehuckss396 on August 28, 2021, 07:15:48 PM
Most of my stock is here!   Way to go Mcmaster!

McMaster Carr has some rediculas delivery times. I actually ordered something at 9AM and got it the next day about 5PM. I have never waited more than 3 or so days for anything. They have very reasonable shipping charges. Only problem is you don't know what the shipping will be until they ship it. Not really a problem, I have never felt like I have been overcharged.
Title: Re: 917 180 degree V 12
Post by: steamer on August 28, 2021, 08:03:51 PM
Most of my stock is here!   Way to go Mcmaster!

McMaster Carr has some rediculas delivery times. I actually ordered something at 9AM and got it the next day about 5PM. I have never waited more than 3 or so days for anything. They have very reasonable shipping charges. Only problem is you don't know what the shipping will be until they ship it. Not really a problem, I have never felt like I have been overcharged.
When you look at deliveryandprice they always have the best deal...not always the cheapest, but the best.
Title: Re: 917 180 degree V 12
Post by: steamer on August 28, 2021, 08:32:50 PM
So what am I up to.

I'm making the crank sections via the Shilling method,   so here they are....in CAD and Finished

The A1 and B1  sides are machined complete while the A2 and B2 sides have some stock left on them at the bearing mount locations

The two halves are machined and assembled on the crank pins, then the sections are located on the A1 B1 side and the A2 B2 bearing features are machined in-situ.

I have all the A1 B1 sides done, as the only difference is the M3 clearance hole/countersink vs a M3 tapped holes

Now I'll be machining the A2 and B2 sides.

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on August 28, 2021, 09:31:02 PM
Hello Dave,

Your off to a flying start. Good idea to get this very difficult crankshaft done and our of the way.

I am assuming the B sides bolt to the A sides, but rotated by 120 degrees, with the main roller bearing sandwiched between the two sides. It may be an idea to mark up the overall crankshaft drawings to identify the A1, A2 ,B1, B2 parts, to make it easier for us, the readers, to follow.

Are the counterweights 'bolt on' additions or are they to be machined as an integral part of each side part (disc)?

There appear to be two counterweights, one on either side of the A1 + A2 sides (discs)?  Are they not also needed on the B1 + B2 sides as well?

I am sure it will become clearer to the readers as you progress

Keep the swarf flying

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on August 28, 2021, 09:40:06 PM
Hello Dave,

Your off to a flying start. Good idea to get this very difficult crankshaft done and our of the way.

I am assuming the B sides bolt to the A sides, but rotated by 120 degrees, with the main roller bearing sandwiched between the two sides. It may be an idea to mark up the overall crankshaft drawings to identify the A1, A2 ,B1, B2 parts, to make it easier for us, the readers, to follow.

Are the counterweights 'bolt on' additions or are they to be machined as an integral part of each side part (disc)?

There appear to be two counterweights, one on either side of the A1 + A2 sides (discs)?  Are they not also needed on the B1 + B2 sides as well?

I am sure it will become clearer to the readers as you progress

Keep the swarf flying

Mike

All counterweights are integral to the crank, and both sides of the web....or more precisely, I'm removing some metal opposite the counterweight and under the bearings.    That'll be some set up for sure....should be fun!   A fairly simple fixture plate on the mill will do fine.
That is what it takes with 2 conrods and 2 pistons at 180 on a common crank pin.

Dave
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on August 28, 2021, 09:42:18 PM
I assume (always dangerous) that the circular part on the end of the last picture/print is the bearing - or ?
Title: Re: 917 180 degree V 12
Post by: steamer on August 28, 2021, 09:46:19 PM
Assembly will be thus

An A section assembly is bolted to the center spur gear. with a bearing

A B assembly is then connected to the OTHER side of the A section. with a bearing

Then another A section is bolted on the B section with a bearing

Then an "End cap" with just the bearing features and no counterweights goes on the very end. with a bearing

A identical Assembly is bolted to the OTHER side of the center gear.....and there you will have a 6 throw 120 degree crankshaft

Title: Re: 917 180 degree V 12
Post by: steamer on August 28, 2021, 09:55:49 PM
Here is the center gear.    with bearing mounting features on either side as well as the tapped holes

Title: Re: 917 180 degree V 12
Post by: steamer on August 28, 2021, 10:05:27 PM
I got my letter designations backwards, so here it is another way

Items with a * are the bearings....which are ultra thin ball bearings which are 25mm ID x 32mm OD x 4mm wide
Title: Re: 917 180 degree V 12
Post by: steamer on August 28, 2021, 10:07:48 PM
So Per....there are 8 main bearings on this crank....

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on August 28, 2021, 10:11:37 PM
I got my letter designations backwards, so here it is another way

Items with a * are the bearings....which are ultra thin ball bearings which are 25mm ID x 32mm OD x 4mm wide

Thanks Dave,

Now that makes more sense.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on August 29, 2021, 02:51:10 AM
And just like that, the other sides are thru first OP.  All together that was 12 inches of 1.25" 1144sp bar.
Title: Re: 917 180 degree V 12
Post by: RReid on August 29, 2021, 02:44:38 PM
I'm looking forward to following your progress on this project! :ThumbsUp: :popcorn:
Title: Re: 917 180 degree V 12
Post by: steamer on August 29, 2021, 03:22:48 PM
Thanks Ron...   Mama is sick, and needs my help today...so hard to say how much of my last vacation day will be in the shop...but I'm hoping...

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 29, 2021, 04:22:13 PM
First mill op Ron...pretty much regardless of type.

Its all in the sequence as I'll be transferring the clamp from the back to the front so I can do all the surfaces in one set up.

Then it's a flip with a fixture pocket, and a tight dowel pin and a clamp for the second side.   


It will be a bit tedious because of the tool changes...but it'll get there

Dave


Title: Re: 917 180 degree V 12
Post by: Vixen on August 29, 2021, 06:36:49 PM
Hello Dave,

Hope Mama is feeling better.

I am following closely and watching just how you set about making your Schillings crankshaft, because it is directly relevant to the one I need to construct for my W165 crankshaft. I have two prime candidate design options under consideration, one of which could use a press fit for the crank pin.

Therefore, I trying to understand the potential problems of achieving a press fits and overall accuracy in the crank discs. Then access, if I can achieve similar precision in my shop; with my machinary.

I see you are proposing to machine both sides and the crank pin bore on the mill. Will the milling alone give sufficient accuracy for the press fit? Or do you have you some additional process in mind; a boring head? a reamer? a hone? some thick glue? or whatever?

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on August 29, 2021, 07:03:49 PM
HI Mike,

Plan A is a shrink/press fit.   .0015 interference.    I will do a circular interpolation bore for the hardened A2 tool steel pin.'

Ive considered a relief groove either on the pin or in the bore, as a loctite back up.

I think that this will result in the most accurate assembly.....

Plan B is a .0015 clearance fit, and some high temp Loctite green retaining compound because "I know that will work!"...but I think it's the least accurate method.
 Loctite both cheeks on, and then with what amounts to a V block fixture, grab the crank by  the crank pin, and turn one side to size, square and parallel, then mount on that diameter and cut the other side concentric.


I'm hoping plan A works......

As far as circular interpolation being accurate?  Not a problem at all.  It'll repeat very well.    If I get nervous, I have a undersize reamer as a back up, but I think interpolating is a better way to go.    Rough with 1 tool and leave the finish bore for a fresh dedicated endmill.

Dave


Title: Re: 917 180 degree V 12
Post by: Vixen on August 29, 2021, 07:54:30 PM
Hello Dave,

It's interesting to hear you feel that circular interpolation on your Tormach will be accurate enough. I guess a few test bore would confirm that and would also help refine the G-code values.

For the built up W165 crankshaft; I have been thinking along the lines of your Plan B. Slight clearance and Loctite 638 green.

My concern is that with a tight clearance, the Loctite will set off too quickly, perhaps before you have time to get the parts all aligned and square. Once the Loctite sets off, your more or less stuffed. Refrigerating the Loctite and the crankshaft parts will buy you a little more time, but will it be enough?

Is there an alternative retainer? Would a high strength Epoxy, such as JB Weld, be a viable alternative? It would certainly give more working time. There is already a good bonding area, a relief grove may be in order to ensure adequate coverage in the joint. It may be possible to maximise the bond strength with additional heating

What does the panel think? Has anyone got comparative bond strength figures?

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on August 29, 2021, 08:14:09 PM
So here is the process in photo form.     Area's in blue being machined

Lathe  Op 1

Mill   Op 2

Mill Op 3

Lathe  Op 4

As to loctite.   It will kick off quicker with a very tight fit than it will with a looser fit.  With Loctite 680, with a  .001 to .0015 fit will give you probably 30 sec to 1 minute to mess with it.   To deal with that, you need an assembly fixture, which Shilling describes.  My second side could be and probably will be a loctite fit as the bearing lands need finishing anyway  ( lathe Op 4 below).    Stay tuned.   

I once put a 16 HP frameless motor for the main spindle drive on a diamond turning lathe, with the stator mounted in the stator housing with nothing by 680.      My calculations at the time showed it would take 85 tons to press it out.  So there was no need to "re enforce" the joint.....it worked fine.     The key is to have very clean joints.   Henkel, in typical German efficiency, publish tech documents on the used of all their products.    If you follow the instructions, you can predict the response.    They are that good.   The documents are all free, and freely available as PDF's online.   

Dave
 
Title: Re: 917 180 degree V 12
Post by: Vixen on August 29, 2021, 10:31:18 PM
Hello Dave,

The strength of a well executed Loctite joint is never in doubt. It could be too strong, too quickly, leading to assembly problems.

I have the relevant Loctite data sheets, that's where I found about the effect of a tight fit in reducing the set off time  and the advice to extend the set off time by refrigeration. 30 seconds to 1 minute is not much time to get everything together and correctly aligned. To do the assembly in less than that time will need a very effective assembly fixture, sliding 'V' blocks or whatever.

Thats why I was looking to see if there were an alternative retainer which could give a longer time for alignment.

Your option A, a press fit, may be the better answer. You can always bump the crank parts into alignment, if necessary. Thats how they do it on many Moto racing two stroke engines. A controlled press fit (lots of them) will be more difficult to machine.

This could be fun

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on August 29, 2021, 10:40:41 PM
Hey Mike,

Yeah....it's not easy....but should be better than trying to turn one from solid.

I think I'm going to try a shrink fit/press fit on the first side.  ( Shrink fit if I can get me hands on some LN2 and a  heat gun)

The second side might be loctite though..    I am thinking a V block with a squared piece of round stock to bank the first side into.   Then slide the second one down directly on the loctite.    The idea being that the press fit will get the pin square to the bearing on the first side, and machining the second side will correct any error in the second from the looser fit.

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 29, 2021, 10:45:24 PM
Oh and I suspect we'll both get lots of practice machining "not so close tolerance" press fits....by several means.....did I mention I have a .0015" under reamer?......if you trust the spindle run out of the spindle/holder....ect.


Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 29, 2021, 11:00:59 PM
Crank pins are A2 precision ground stock sized at -0/ +8 microns.   Plan is part and face to length, and bore to reduce weight.   ( 17/64 or 0.265" which is 0.010" under 7mm) .  Then harden them full hard and draw to 400F  some where around 45-50 Rc.           I have  3C collets for this size so I'm half way there for the joint.

the bore is going to be the tough part.    I'm going to set up to cut these parts in one go, and like I said, the bore is done with a fresh end mill and a circular interpolation boring strategy as found in Fusion.   I've had very good luck with that in the past....so I'll give it a shot.   If I have trouble, I'll try the reamer....failing that, we go loctite.

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on August 30, 2021, 12:55:32 AM
First mill op setup
Title: Re: 917 180 degree V 12
Post by: steamer on August 31, 2021, 03:19:02 PM
Ok Mike.  I think I've come up with a suitable, realistic and repeatable solution.   Stay tuned....at work now..doin work things
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on August 31, 2021, 04:50:56 PM
Dave - it might not be helpful .... but going to bed last night, my mind suddenly voiced concern with the torsional forces on the M3 bolts in your crank assembly .... and kind of had a possible solution ....  :thinking:

Imagine the circle divided by 6 into 60 degree sections and milling out every second one. This should give you a spacing of 120 degrees (or multiply of) and torsional locking. Of course the M3s should still clamp "sideways" onto the bearings and not onto the millied out portions I mention.

I know that this is not what you and Mike are debating right now .... but if my idea is useful - it should be implemented before you assemble the parts, as the two of you debate.

Per
Title: Re: 917 180 degree V 12
Post by: steamer on August 31, 2021, 05:27:31 PM
Thanks Per.   I will review that, but Schilling got away with just bolts  ,M4's on a much larger engine....I think it will be alright, but failing that I could just pin them together.

Mike   attached is the loctite fixture I was thinking about

Think about it

Dave   
Title: Re: 917 180 degree V 12
Post by: Vixen on August 31, 2021, 07:03:54 PM
Dave,

You/we are certainly going to need an assembly fixture something like that, to hold the two halves square while they are pushed together with the Loctite in the bore.

I am still worried about the speed with which the Loctite sets-off. 30 seconds to a minute ain't much time, even refrigeration will only buy a small amount of extra time. It's a pity there was not a "slow" Loctite or a retarder of some type.

I am still considering a high strength Epoxy as opposed to Loctite to increase the working time. It may need to be a liquid rather than a paste.

Per,

Dave could also consider 6 off high tensile M3 bolts or three bolts and three pins, if torque becomes an issue.

Mike  :DrinkPint:
Title: Re: 917 180 degree V 12
Post by: Roger B on August 31, 2021, 07:26:25 PM
Shillings book can be found on the internet but is obviously in German.
Title: Re: 917 180 degree V 12
Post by: Vixen on August 31, 2021, 07:32:14 PM
Hello Roger,

Jason posted a link to the Schillings book. You can find a PDF at

https://www.dropbox.com/sh/r9vwan9g65hgoau/AACw63yvd7BQJGJUpW6M11DUa?dl=0&preview=Schillings-Buch.pdf

The pictures and drawings speak for themselves.

Mike
Title: Re: 917 180 degree V 12
Post by: Roger B on August 31, 2021, 07:55:49 PM
Hello Mike,

Yes I have the book and have enjoyed it. I downloaded it for his fuel injection system however it is a continuous flow system not timed injection.
Title: Re: 917 180 degree V 12
Post by: steamer on August 31, 2021, 09:39:12 PM
These secod cheek gets its bearing surface machined after assembly with loctite.  Getting the pin square to the first one is the key.  That gets the fixture above.


Dave
Title: Re: 917 180 degree V 12
Post by: steamer on September 03, 2021, 01:32:59 AM
Per
Here we go.    M4 x 0.7 and twin 7mm drive pins ...

Now lets get on with it!    8)
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on September 03, 2021, 07:50:15 PM
Looks really good Dave  :ThumbsUp:    I like it    :cheers:

Come to think of it (my bad memory - it comes and goes) .... I kind of thought (when I read the book first time) that all the web had 3 holes 120 apart that would take a long pin, that was both the conrod bearing + locked the neighbours in place on the other side of the bearings + the holes for the bolts to keep them together.

I see that you can do something similar - though locked in place sideways.

Per
Title: Re: 917 180 degree V 12
Post by: steamer on September 04, 2021, 08:56:03 PM
Looks really good Dave  :ThumbsUp:    I like it    :cheers:

Come to think of it (my bad memory - it comes and goes) .... I kind of thought (when I read the book first time) that all the web had 3 holes 120 apart that would take a long pin, that was both the conrod bearing + locked the neighbours in place on the other side of the bearings + the holes for the bolts to keep them together.

I see that you can do something similar - though locked in place sideways.

Per

The problem you run into is    I have to balance 2 rods, 2 pistons and 2 wristpins on one crank throw.   This is a 180 degree V12....which means the crank throws are at 120 degrees and two rods per throw....which is completely different than say a "boxer" engine with 180 degree throws and diametrically opposed.  They tend to self balance......

There's a reason Porsche used Ti con rods.....

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on September 04, 2021, 09:02:36 PM
And heres a view with 1 half of the crankcase removed.     

Title: Re: 917 180 degree V 12
Post by: crueby on September 04, 2021, 09:07:37 PM
Sorry if this has been covered earlier - but I am a little confused by the title - a 180 degree V 12. If the pistons are 180 degrees opposed, which it looks like from the pictures, why is it called a V 12? I must be missing something in the layout?   :headscratch:
Title: Re: 917 180 degree V 12
Post by: steamer on September 04, 2021, 10:06:58 PM
Sorry if this has been covered earlier - but I am a little confused by the title - a 180 degree V 12. If the pistons are 180 degrees opposed, which it looks like from the pictures, why is it called a V 12? I must be missing something in the layout?   :headscratch:

180 degrees is the bank angle....the most common V12 bank angle is 60 degrees, but there are others.

It's considered a V12 because a boxer 12 would have 1 pin per cylinder and be 180 opposed to it's neighbor where a V 12 has two pistons on one pin with even divided firing angles.

https://www.youtube.com/watch?v=IEgXUt1PSgg

Title: Re: 917 180 degree V 12
Post by: crueby on September 04, 2021, 10:16:28 PM
Sorry if this has been covered earlier - but I am a little confused by the title - a 180 degree V 12. If the pistons are 180 degrees opposed, which it looks like from the pictures, why is it called a V 12? I must be missing something in the layout?   :headscratch:

180 degrees is the bank angle....the most common V12 bank angle is 60 degrees, but there are others.

It's considered a V12 because a boxer 12 would have 1 pin per cylinder and be 180 opposed to it's neighbor where a V 12 has two pistons on one pin with even divided firing angles.

[youtube1]https://youtu.be/IEgXUt1PSgg[/youtube1]
Okay. I always thought that a V engine would be something other than 180, like a, well, Vee shape. I'd have called this a flat 12, but I'm not a car expert.


Thanks!
Title: Re: 917 180 degree V 12
Post by: steamer on September 04, 2021, 10:19:01 PM
Here's a boxer layout

https://www.bing.com/videos/search?q=Diagram+of+a+Boxer+Engine&&view=detail&mid=F64282AE1A1BD95597ADF64282AE1A1BD95597AD&&FORM=VRDGAR&ru=%2Fvideos%2Fsearch%3Fq%3DDiagram%2Bof%2Ba%2BBoxer%2BEngine%26FORM%3DVDMHRS

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on September 04, 2021, 10:22:05 PM
It is a flat 12....but not a boxer.....which is why it's called a 180 degree V12

Dave
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on September 05, 2021, 12:29:19 AM
Quote
which is completely different than say a "boxer" engine with 180 degree throws and diametrically opposed.  They tend to self balance......

Ops - once again I jump into the Ass-U-Me trap  :embarassed:  of always think of Porches as Boxers ....
Just because they originally started that way - way back in time ..... doesn't mean that they always did .... again Ups .... my bad.
And to make it worse - I have looked at your nice pictures and drawings, and still not connected the dots correctly ....

In the end I kind of expect it to balance like a Straight Six (or somewhat close) - some of the upper harmonics might be a bit different. The boxer might have a slightly better balance as a twelve and much better with other cylinder numbers.

I can see their reason - smaller length, lighter crank, better torsional stiffness of crank => higher Max RPM. => higher Power.
But as you mention - it does make it harder to get the balance right. I hope that the CAD will help you here.
Title: Re: 917 180 degree V 12
Post by: steamer on September 05, 2021, 01:26:22 AM
And remember Per....Porsche took all the power from the middle of the crank, not the end

That makes for a much less crank torsional deflection.

Dave
Title: Re: 917 180 degree V 12
Post by: Vixen on September 05, 2021, 09:21:17 AM

Ops - once again I jump into the Ass-U-Me trap  :embarassed:  of always think of Porches as Boxers ....
Just because they originally started that way - way back in time ..... doesn't mean that they always did .... again Ups .... my bad.
And to make it worse - I have looked at your nice pictures and drawings, and still not connected the dots correctly ....


Per, it's quite reasonable to assume that all Porsche engines, both road and track are boxer engines. Almost all were.

The long succession Porsche sports/ racing cars began in 1948 with the 365 powered by a 4 cylinder air cooled boxer engine.

The 911 started life in 1963 with a 6 cylinder air cooled boxer engine which changed to liquid cooling in 1998 but still retained the 6 cylinder boxer configuration. The 911 is still being raced today, it's been motor racing for nearly 60 years, an unequaled achievement. No wonder they are called 'Roach Racers" not just for their shape. Like the Cockroach, they have evolved over many generations to become very fast and near indestructible.

The 917 (1969 to 1973) was the odd one out, being a 180* V12 but still retained the flat air cooled layout. It was unbeatable at Le Mans and CanAm

For the 1980's Porsche returned to the 6 cylinder air cooled boxer configuration for the 956. The 956 went on to dominate  Group C sports car racing and Le mans for another ten years.

There are many other boxer engined Porsche's. The ones above are the most notable and successful.

Mike



Title: Re: 917 180 degree V 12
Post by: steamer on September 05, 2021, 09:10:20 PM
Mama's honey do game is strong this weekend......but I'm making progress
Lots of ops on these crank cheeks....


Title: Re: 917 180 degree V 12
Post by: steamer on September 06, 2021, 12:03:04 AM
Ok    first part off the machine.  I have the wrong clearance drill but the crank pin hole was exactly to size   .001 press fit.
It begins!
Title: Re: 917 180 degree V 12
Post by: stevehuckss396 on September 06, 2021, 10:35:58 AM
Boom!  And so it begins! 
Title: Re: 917 180 degree V 12
Post by: Vixen on September 06, 2021, 10:49:47 AM
Hello Dave,

This is the start of something big.  :ThumbsUp: :ThumbsUp: :ThumbsUp:

It's pay back time for all the effort you have put into the design and drawings.

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on September 06, 2021, 11:20:31 AM
Thank you Mike and Steve ( Bubba)
 8)

I've got a good feeling about this, and it's nice not having to Engineer on the fly.   I know what needs to be made.....so get on with it!

That said....More Honey dos today.   My daughter, whos been in isolation for the duration of her cancer treatments can finally have some of her friends come see her.   it wont be for a couple of weeks I think, but I'm trying to get the back yard patio into some semblance of presentable, a tent and tables sourced and erected, ect.

I'll probably get back into the shop later this afternoon.   

I have 3 more of the "Side B's" and then 2 "Side A's".. 

These disks have the bearing diameter on the far side complete.    The other 6 parts will be machined complete, but have the bearing surfaces only roughed to plus .020".   The reason for this, is to finish the bearing diameter after assembly, which dials out some of the stack errors in the parts   This is in keeping with Shilling's precepts.        I had planned to do this final machining in the lathe.....but I'm not so sure!....The Tormach might be pressed into service!    I'm very pleased with that auction buy that's for sure!!!

I'm going to finish the parts for this set up, and evaluate.   Then I'll either make a fixture for the lathe, or the mill to hold the assemblies for machining.

Dave


Title: Re: 917 180 degree V 12
Post by: Vixen on September 06, 2021, 12:01:10 PM

That said....More Honey dos today.   My daughter, whos been in isolation for the duration of her cancer treatments can finally have some of her friends come see her.   it wont be for a couple of weeks I think, but I'm trying to get the back yard patio into some semblance of presentable, a tent and tables sourced and erected, ect.

Dave

Hey Dave,

Thats even better news about Ava, than hearing you have made a start on the 917     :cartwheel: :cartwheel:

Mike
Title: Re: 917 180 degree V 12
Post by: steamer on September 06, 2021, 12:06:10 PM

That said....More Honey dos today.   My daughter, whos been in isolation for the duration of her cancer treatments can finally have some of her friends come see her.   it wont be for a couple of weeks I think, but I'm trying to get the back yard patio into some semblance of presentable, a tent and tables sourced and erected, ect.

Dave

Hey Dave,

Thats even better news about Ava, than hearing you have made a start on the 917     :cartwheel: :cartwheel:

Mike

Isn't it though?!     Tough kid!!!

Title: Re: 917 180 degree V 12
Post by: steamer on September 06, 2021, 04:18:12 PM
Ok  so later today I'll start a build thread   
 1/4 scale Porsche 917 180 degree V12

And I'll refer this thread to there and vise versa.  The design thread is done.      8)
Title: Re: 917 180 degree V 12
Post by: Admiral_dk on September 06, 2021, 07:11:49 PM
I will have to agree with Mike - Very good news about Ava  :cartwheel:
I hope that she will have a very good time with friends  :cheers:

Nice parts Dave - see you on the build thread  :D
Title: Re: 917 180 degree V 12
Post by: steamer on September 06, 2021, 10:26:15 PM
Link to build thread

https://www.modelenginemaker.com/index.php?topic=10504.msg240595#msg240595
Title: Re: 917 180 degree V 12
Post by: Dave Otto on September 07, 2021, 01:21:56 AM
I thought this was the build thread? I'm so confused.

Dave
Title: Re: 917 180 degree V 12
Post by: steamer on September 07, 2021, 01:37:23 AM
I thought this was the build thread? I'm so confused.

Dave

I'm sorry for the confusion Dave.....Actually this is the design and discussion thread.    Now that it's 53 pages long, and I'm cutting metal,   I'm kinda done with the design.......so to make it easy for the members who may be just tuning in,  (we're at 50 pages now...)  I started a build thread.

Dave
SimplePortal 2.3.5 © 2008-2012, SimplePortal