1/6 Porsche 917 Engine Full Detail

[Formulamike]

Yes that it is, the next level of modelkits, great to see it, many thanks for sharing this pics. ,
Yes we enjoy this.
Mike

[VR2]

Hi there and a merry christmas to all !

Thanks a lot for your interest in this "niche" project. At the beginning I was a bit hesitant to post this project on F1M as this is something different than building complete cars and bikes.

In the meantime, I could finish the lower shaft along with the gears, bearings and the flywheel. Except the gears (3D printed), all other parts have been machined according to original drawings. The shaft is running in three sleeves with roller bearings to minimize mechanical frictions.

Parts overview of lower shaft with flywheel:

Lower shaft assembled with flywheel mounting thread and thoothed inner sleeve:

Flywheel mounted on shaft and fixed by lock nut:

Lower shaft mounted in crankcase. Mounting studs installed on both halves of crankcase. What can be also seen are the two suction devices, which belong to the dry sump system:

Connoisseurs love the wonderful mechanical "rattling noises" of the 917 engine which originate from the gear-driven camshaft timing control. The model will get all gears according to the original:

And now to the real funny (hopefully not disappointing) part of the project. My goal is to make this model mechanically fully functional, meaning that all gears, shafts, valves, fan, distributor, etc. shall rotate/move like the original. The challenge is to manage the issue with tolerances (mainly with the 3D printed parts). A tenth of a millimeter deviation here and there can easily lead to frictions or totally block the movements. To not get hit by surprise with the final model, I've designed a experimental prototype with only four cylinders on which I can test all relevant mechanical functions and make adjustments (crankshaft, con rods, pistons running in cylinders and the timing gears for the camshafts).

On this picture, the experimental prototype can be seen on the right side. I've made a first test with the crankshaft and central gear (running in lubricated bering shells) successfully running at a speed of up to 22.000 rpm (driven by a handheld Proxxon micromot). A tiny step compared to the complex setup of the overall mechanical dependencies but at least a hint that this might be achievable.

As next step, I plan to add the con-rods, pistons and cylinders .. we'll see whether this setup still survives 22.000 rpm ???

BR, Uli

[CK]

Hu Uli,

Bravo! What a project. I admire your skill and courage to tackle a big project like this!

[sky1911]

Ach Uli,

this is going to be another master piece. As a funny side note. On seeing the title pop up again, I was reminded of the 1/4 Porsche 911 engine you can buy on Am@zon (and other places) and that basically is a toy, despite the opportunity to add even more detail due to the slightly larger size. This, however, is awesome. I am half expecting it to fire up once it is completed

[gp-models]

Pffffffff !!!
I bet you also created a scaled down torque spanner for the screws and the crankshaft is finely balanced!

Amazing Uli, absolutely amazing work! I think your working on a scaled down oil as well in a laboratory!

[Belugawrx]

So.. when are you going to start posting pictures of the model you are making..?

lol

Wow what a wonderful WIP to watch, beautiful model, photography and composition is exceptional.
I look forward to updates and will remain, inspired. Thank you
Cheers

[turboF1]

Beautiful work!
After 1/6 scale might as well just go 1:1 scale. Imagine it firing up ..,

[43rdMichael]

Superb!!! Thanks for posting this. I would say inspirational, but let’s be honest, i’m not up to anything this project would inspire me to try.
I’ll just sit back and enjoy the ride!!

[VR2]

Hi and thanks for your your nice comments

Design work on the engine continues and I've decided to build this engine (naturally aspirated version) in 3 different scales:

- 1:6 as one-off model
- 1:8 (can be placed next to a Amalgam 917 or to the announced 917 Pink-Pig of Minichamp)
- 1:12 (for MFH 917 models)

The most critical parts in 1:12 are the cylinders and the cylinder heads because of the extremely thin cooling fins. Especially when made with the right number of fins and the complex geometry of the cylinder head (combustion chamber, intake/exhaust channels, guidance of the valves and spark plugs, etc.). As for all parts, the cylinder and cylinder head was designed in 1:1 and scaled down before printing and here are the results, which has proven, that the cycinder parts can be produced in 1:12 with the same level of details as in 1:1 ! Key however was to find the right print settings along with the orientation on the platform and a print support structure, which doesn't negatively impact the crisp details.

First feasibility study of the cylinders - already very promising. Support structure however has been changed/further improved in the meantime:

Finished cylinder and cylinder head in different scales to prove that it can be done "down" to 1:12:

Comparison of MFH kit parts vs. 3D printed. The difference is obvious and also shows the process limitations of white metal casting:

Now it's time to design the con-rod and piston ...

Best regards,
Uli

[gp-models]

Incredible work! Another masterpiece on it`s way from you, like it!