Porsche 917 flat 12 engine

[Foketry]

Should be 'a piece of cake' compared to Normans....

Napier dagger , it's an amazing engine, they look like 2 Porsche 917 engines stacked on top of each other ...

 

[Foketry]

When assembling crank pin with flywheel under press, I discovered this error, the hardened material is too brittle, the pins break ! Diameter is 12mm (.43 inc)
This material is tool steel, used for reamers and taps: 115CrV3 ( European standard) , L2 Aisi/SAE standard (USA), easy to harden in water or oil, but after quenching at 790 degrees C , tempering at 250 degrees is required to reduce fragility.

this break is also favored by the sharp edge of the groove for oil distribution and the hole.
it would be appropriate to make a radius at the bottom of the groove, but now all the pieces are done

I'll do tempering at 250 C°

 

[Foketry]

I assembled the crankshaft : connecting rod , flywheels , internal bushings and gear.
To ensure perfect alignment of the flywheels I made a final turning on external diameter, I left an allowance of 0.5 mm
The space between one flywheel and the other has been filled with glued wood to avoid distortions between the tailstocks

The original Porsche crankshaft

 

[Alec Ryals]

When assembling crank pin with flywheel under press, I discovered this error, the hardened material is too brittle, the pins break ! Diameter is 12mm (.43 inc)
This material is tool steel, used for reamers and taps: 115CrV3 ( European standard) , L2 Aisi/SAE standard (USA), easy to harden in water or oil, but after quenching at 790 degrees C , tempering at 250 degrees is required to reduce fragility.

this break is also favored by the sharp edge of the groove for oil distribution and the hole.
it would be appropriate to make a radius at the bottom of the groove, but now all the pieces are done

I'll do tempering at 250 C°

View attachment 123887

Higher temper temp

 

[SPOTTER]

Fantastic work, it's a pleasure for the eyes

 

[Foketry]

Before final turning I checked if all the internal oil passages were open, the oil from a hole at the beginning of the crankshaft must flow to the last hole of the connecting rod and last flywheel.
I used WD40 for this test , a small gerotor pump and a cordless drill
before final turning

 

[Foketry]

Engine block from Porsche museum

 

[Foketry]

My 3D drawing of the engine block
they are 2 half crankcases almost equal, the difference is that the 6 cylinders on the right are displaced by 9 mm compared to the 6 cylinders on the left (the thickness of the connecting rod + 1 mm)
There are 2 slots for 2 distributors, one on one half crankcase, the other on the other half crankcase
The top transmission shaft drives 2 distributors and the fan, the bottom shaft drives the oil pumps and the large central seat houses the crankshaft.

 

[Foketry]

for a whole night the printer created the foundry mold , compared to the finished engine block I had to foresee the machining allowances and the 2% shrinkage of aluminum.
I had to print the 2 engine casings in 4 pieces (2 + 2) because the dimensions of my printer are small
Then I glued the pieces together

 

[The_reach]

Seriously impressive progress on this, looking forward to seeing how the castings turn out

 

[Alec Ryals]

I assembled the crankshaft : connecting rod , flywheels , internal bushings and gear.
To ensure perfect alignment of the flywheels I made a final turning on external diameter, I left an allowance of 0.5 mm
The space between one flywheel and the other has been filled with glued wood to avoid distortions between the tailstocks

View attachment 123991

View attachment 123992

View attachment 123993

The original Porsche crankshaft

View attachment 123994
[/QUOTE were did you get the shell bearings ?

 

[jetstuff]

T

Napier dagger , it's an amazing engine, they look like 2 Porsche 917 engines stacked on top of each other ...

Your work is looking great, hope you get to complete it. Normans Dagger was manually machined from solid, No castings /No CNC .

 

[Foketry]

Today the first aluminum casting, half engine block for 6 cylinders

the pattern in petrobond sand ,internal side

Front side

 

[FTX]

I

Great job.

Ftx

 

[michelko]

Today the first aluminum casting, half engine block for 6 cylinders

the pattern in petrobond sand ,internal side

View attachment 124200
View attachment 124203

Front side

View attachment 124204


View attachment 124205

All i can say is WOW ! I wish i could visit you in your shop and watch you doing that magic stuff.
Can you show a pic with an outside view of the case half?

 

[Foketry]

Today the other aluminum casting , the printer has worked all night for second mold

 

[Foketry]

All i can say is WOW ! I wish i could visit you in your shop and watch you doing that magic stuff.
Can you show a pic with an outside view of the case half?

Hi Michael , you can see the other side in this photo

 

[aarggh]

Fantastic work! The castings came out brilliantly!

Do you use any type of compounds to degas/flux when casting to get such a good result?

 

[Foketry]

Fantastic work! The castings came out brilliantly!

Do you use any type of compounds to degas/flux when casting to get such a good result?

I have used sodium carbonate in the past, I also tried degassing flux tablets with not always good results
Now I use quality aluminum of a single type (AlSi9Cu) without degassers or fluxes, no porosity, no internal defects
I'm not very experienced but I realized that using aluminum scraps of unknown quality does not always lead to good castings

 

[Foketry]

Outside milling of the engine block, cylinder housing and drilling
the rectangular window in the center is for the camshaft drive gears