Porsche 917 flat 12 engine

[Foketry]

Transmission gears test

 

[michelko]

Transmission gears test

Thats realy impressive. You are doing magic.

 

[Foketry]

Dry sump oil pump and filter
This racing engine has 7 pumps, 4 scavenge and 3 for pressure ,I am trying to do everything with one pump, not sure if everything will work, but I would like to try it.
My crankshaft is internally drilled, a 4 mm hole goes through the whole shaft to lubricate all the bushings, 20 positions where oil comes out (i hope) , my 4 camshafts are grease lubricated

Original engine wiht External pump

3-stage internal pump, 2 scavenge 1 pressure

 

[Foketry]

The hydraulic circuit of a Porsche 917 dry sump engine , but I have simplified the scheme a lot, no oil tank , non oil cooler ,I don't have to do race.

 

[a41capt]

The hydraulic circuit of a Porsche 917 dry sump engine , but I have simplified the scheme a lot, no oil tank , non oil cooler ,I don't have to do race.

View attachment 130508

I’m thinking that you’re not going to run the 24 hours of LeMans, so redundancy on oil pumps (even though that may have been a secondary consideration/benefit of the original design) probably is unnecessary. Chances are you’ll see what the end of circuit oil pressure looks like before it becomes critical.

Beautiful work so far, looking forward to the first “pop”!

John W

 

[Foketry]

My first problem to solve was : what kind of pump ? gear pump or gerotor pump ?

The square pump is Volkswagen automatic transmission pump , more than 100 bar, up to 4000 rpm
the triangular pump is a gerotor pump for moped , the technical characteristics are unknown, cost : few euros

I did a bench test for both, the Wolkswagen gear pump only works with low viscosity hydraulic oil, the motor oil is too hard and the pump has cavitation due to inadequate flow. the oil inlet hole could be enlarged, but there is little space.

The gerotor pump has a low pressure, a sufficient flow rate and the oil passes through the entire crankshaft and also exits through the furthest bearing hole.
I therefore use this small pump.

 

[Foketry]

Oil filter: I looked for a small oil filter whose dimensions were compatible with my engine model , I found a very small filter in Italy, it is a Piaggio Vespa replacement

 

[Foketry]

I place pump in the side cover, the oil that comes out of the crankshaft holes falls into the crankcase, from here by gravity reaches the pump intake hole and is pumped under pressure through the filter and then on one side of the crankshaft.
Here an oil seal with a lip facing outwards allows the oil to exit only through the inlet hole of the crankshaft.

in this old design the pump was inside crankcase, but is now external

 

[Foketry]

Pump cover: drawing, 3D model pattern , aluminum casting

 

[ddmckee54]

I see very few layer lines on the casting. Do you just sand the patterns, sand and fill them, or something else? How big is the casting? Judging from the fingers in the picture, I'm guessing it's about 4 inches long?

Don

 

[Foketry]

I see very few layer lines on the casting. Do you just sand the patterns, sand and fill them, or something else? How big is the casting? Judging from the fingers in the picture, I'm guessing it's about 4 inches long?

Don

Pattern is painted with polyester filler and sanded , the length is 5.3 inches
Casting is not perfect, there was a shrinkage in the upper part where the thicknesses are large, due to the lack of aluminum supply during cooling, I should have placed vent or feeder in that area . It's a lesson learned for next time.

 

[ddmckee54]

So is this casting still usable, or will you re-cast it?

 

[Foketry]

So is this casting still usable, or will you re-cast it?

it is a cosmetic defect that can be solved, I can use it after a little file work

 

[Foketry]

covers with installed pump

 

[Foketry]

 

[Foketry]

some machining, cover and seal ring seat

 

[michelko]

Man thats a real clever design on the oiling system

 

[ddmckee54]

Foketry:

I get it that the oil seal stops leaks around the crankshaft as it's rotating, allowing the crank to be pressurized by the oil chamber. But what seals the oil chamber to the crankcase? Is there a gasket that is yet to be installed? Leaving it out for now would be understandable if you're just checking the fit of the parts.

Don

 

[michelko]

I used Curil with good results for this

 

[Foketry]

Foketry:

I get it that the oil seal stops leaks around the crankshaft as it's rotating, allowing the crank to be pressurized by the oil chamber. But what seals the oil chamber to the crankcase? Is there a gasket that is yet to be installed? Leaving it out for now would be understandable if you're just checking the fit of the parts.

Don

I normally use this Loctite product for all gaskets below 200 degrees centigrade :
Here you can see data sheet
LOCTITE SI 5940