Porsche 917 flat 12 engine

[Foketry]

Hoop fan housing and bellmouth mounts

I made the cones by deforming an aluminum tube with a conical mold, the first one I made is cracked, I solved the problem by annealing the tube and keeping the flame even during pressing.
Of course cones are fake, there will be a carburetor every 6 cylinders, instead of injection.

The colored pieces in the photos are 3D printed, painted with primer and yellow final top coat.

 

[Basil]

That does look awesome. Amazing build!! Cant wait to see it run. I have an interested to see how the large diameter mains work. I have previously thought many times on this approach but never had the courage to try it. Theory of course says that drag will be on the high side but these engines we build are for the most part not being used for any power producing purposes. I very much hope too see it run brilliantly.

 

[a41capt]

Truly beautiful engineering Foketry! I too cannot wait to hear it come to life, it’ll be an amazing event!

John W

 

[propclock]

Fantastic. Thanks for all your posts.

 

[Thommo]

Hoop fan housing and bellmouth mounts

I made the cones by deforming an aluminum tube with a conical mold, the first one I made is cracked, I solved the problem by annealing the tube and keeping the flame even during pressing.
Of course cones are fake, there will be a carburetor every 6 cylinders, instead of injection.

The colored pieces in the photos are 3D printed, painted with primer and yellow final top coat.



View attachment 131698View attachment 131699


I have just seen the scale of this engine and I’m even more impressed. I thought it was around 400mm long and I see that it’s more like 250. Wow, wow and wow. Mr Foketry you truly are an amazing craftsman. Can’t wait to hear it roar.


View attachment 131700

 

[Foketry]

Fan conveyor

In original engine, a system of aluminum sheets conveys the air flow from fan towards cylinders and heads.
This ensures proper cooling of the engine, remember that this engine won the Le Mans 24 hours race for many years.
In order not to hide all the work done, I preferred to use a Makrolon sheet (similar to Plexiglass) to make this conveyor.
MaKrolon can resist temperatures up to 160 degrees C

my draw

milling, end mill 4 mm, 9000 rpm

 

[Foketry]

After milling, the 4 edges had to be bent , I used this method seen on Youtube recovering the resistance from an old hair dryer

 

[Foketry]

 

[Foketry]

Exhaust pipes and gearbox

After countless attempts and scraps , I assembled the exhaust pipes
I used 12 pipes with external diameter of 12 mm (about half an inch), internal 10 mm and 4 pipes with 20 mm external diameter. I filled the pipes with sand , I screwed 2 caps at the ends, heated the pipes until they reached red color and bent. The internal sand does not allow the pipe to get crushed.
All the tubes were silver brazing with a welding jig to keep them in correct position. I painted everything with 800 C paint for mufflers.

Porsche engine

My Engine
The original Porsche exhausts have a strange shape, 6 in one, I was willing to copy this geometry but then I decided to make 4 main exhaust pipes instead of just 2.

 

[Foketry]

To connect the 3 pipes together I made a brass casting , each tube is fixed to the head with a brass flange, 3 screws and a Viton oring.

some scraps

 

[michelko]

Sweet.
Greetings from italy.

 

[Basil]

Very impressive!

 

[a41capt]

Nice bit of “plumbing”! Did you use your heads as the target block, or make a special form?

John W

 

[ddmckee54]

At the job I had many years ago - I used to have to bend up replacement hydraulic lines for machine tools. We also had plenty of "rejects" in the scrap barrel, and we always checked the scrap barrel first to see if we could make a reject work for the line we wanted.

It doesn't take much of a boo-boo to turn a good part into a bad part does it? Not a problem for you with the exhaust headers, but putting the nut on backwards before you make the final flare in a tube is SOOOO easy to do.

Don

 

[Foketry]

Nice bit of “plumbing”! Did you use your heads as the target block, or make a special form?

John W

As you can see in the second to last photo, I clamped in a vice a rectangular aluminum tube with center distance of holes equal to the distance between heads.
On this tool I also fixed the brass flanges with 3 screws during silver brazing.

 

[Foketry]

Sweet.
Greetings from italy.

Are you in Italy now ?

 

[michelko]

Are you in Italy now ?

Yes we are skiing in obereggen/predazo/pampeago.

 

[Steamchick]

I think that is an expert job! When it looks so simple - and right - there is an expert at work. Thanks for the insights into your work. It sets a standard I (or "many of us"?) don't even dream of achieving!
Well done!
K2

 

[Thommo]

I just cannot wait to hear this beast run!!!

 

[a41capt]

As you can see in the second to last photo, I clamped in a vice a rectangular aluminum tube with center distance of holes equal to the distance between heads.
On this tool I also fixed the brass flanges with 3 screws during silver brazing.

View attachment 132305

Sorry, I completely overlooked the picture you mention! While in the US Navy, my rating was Shipfitter which included all different forms of ship’s repair duties. From heavy plate, sheetmetal, high pressure hull and pipe welding, and fitting new pipes. As you can imagine, removing formed pipes that were damaged back to my Tender ship to rebuild, we would be faced with alignment issues with flanges, and also need to replicate obstructions and precise bends. That is where the “Target Deck” came in handy as we were able to bolt the original piping to flanges welded to stands, and additional marker pieces as obstructions/bend points.

Your aluminum plate in a vise approximates our old target deck perfectly. Thanks for the clarification.

John W