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.......

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
http://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?

p1wpi2o1Q2o
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

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.....

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!

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.....

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