Mercedes-Benz W165 Grand Prix engine in 1:3 scale

[crueby]

More wow's - I was really impressed reading through that post, then I got to the statement about repeating it all for the OTHER crankshaft! Wow.   

[cnr6400]

 

I just hope Crash wasn't stuffing a scale sized apple core up an oilway while he had his mitts in the crankcase! 

[Kim]

That is really impressive, Mike!  Just amazing planning and craftsmanship! 

Kim

[RReid]

Great to see you making real progress again, Mike. I always look forward to your updates.

[petertha]

That's just beautiful, Mike. You are making me increasingly interested in a 'straight' engine once this 'round' engine of mine is complete. I stared at the Schillings drawings & could visualize the parts, but not really the subtleties of assembly.

I want to make sure I understand your mating contact areas during bolt up. Where you have the red X (my red arrow), are those crankpin bosses slightly counterbored so the face to face contact is kind of like an annular ring? Because I also see a flush faces on the blue circles. Or maybe that is just CAD making the dimensions exact?

Is there any Loctite type retainer involved in this process along the way, or all step by step mechanical fastening?

[Vixen]

Thanks to everyone who has looked in and especially to those who made the effort to post a reply. Your feedback is my reward for creating these progress reports.

Petertha,

 Sorry to distract you from radial engines. Remember always "Real engines are round".

The Schillings built up crankshaft illustration ( created by Steamer, relating to his Porsche 917 built up crankshaft) is a generic illustration of the principal. My crankshaft design is slightly different and is shown below.






In my design the crank pins ( marked by the blue circles) are a tight fit into the precision ground ball bearings inners; which provides the crankshaft alignment. There are two radial alignment/ drive pins in each of the main and con rod crankpins. one side of the alignment /drive pins are a tight fit in it's crankpin, the other side is a non interference fit; to ease fitting and dismantling.

In my design, there is a 20 thou gap between the crankpin ends (marked by the red crosses) NOT as shown in the illustration. This gap ensures the two crankpin end faces do not touch and so do not interfere with the alignment provided by the precision ground ball bearing inners.

At the moment I have used no Loctite retainer. I am uncomfortable about this and intend to use a light threadlock to prevent any of the clamping bolts from vibrating loose.

Cheers

Mike

[Roger B]

Magnificent as ever  I'm glad you are over the worst of the Covid problem.

I have often looked at the Schillings crankshaft design in his book/articles and it is good to see yours and Steamers builds 

[Vixen]

Crankshaft and Camshaft gear train

Thank you Roger, for your kind comments and good wishes.

Both Dave (Steamer) and I have now successfully built Schilling style built-up crankshafts. The Porsche 917 being a flat V12 and the MB W165 being a 90* V8. We talked together a lot, while we were working out the two individual designs. The alignment accuracy seems to be totally dependent on the accuracy of the lathe work, in particular, the accuracy and repeatability of the crankpin offset fixture for turning the big end journals.

I could not resist bolting on the camshaft drive train and the two cylinder blocks. The whole lot turned over as smooth and sweet as you could wish; no bumps or lumps in the drive train. Another big step forward.

I wish I knew of a simple way to add a video to these posts. Still photos have their place but sometimes a video adds so much more.







Crash, don't come crying to me if you get your finger nipped in the gear mesh.

Cheers

Mike

[Admiral_dk]

I haven't had time to enter this site for two days .... and what an update while I'm away 

The final pictures shows a piece of art       (I suppose that some of the praise must got to Mercedes-Benz too - as your build is a very faithful Replica)  Mike

Some of my Suzuki Motorcycles had buildup crankshafts and the Original Service Manuals always shows those thin shims (available in a number of thiknesses) - but your build is the first time I hear about anybody I know, having to deal with this issue.
So while you have learned much assembling the first Crank - I don't think you will completely avoid having to assemble parts - just to measure and disassemble for a different thinkness shim a number of times here too 

Great to see that you're back to being in the Sheed and Enjoying your time there     

Per

[steamer]

I haven't had time to enter this site for two days .... and what an update while I'm away 

The final pictures shows a piece of art       (I suppose that some of the praise must got to Mercedes-Benz too - as your build is a very faithful Replica)  Mike

Some of my Suzuki Motorcycles had buildup crankshafts and the Original Service Manuals always shows those thin shims (available in a number of thiknesses) - but your build is the first time I hear about anybody I know, having to deal with this issue.
So while you have learned much assembling the first Crank - I don't think you will completely avoid having to assemble parts - just to measure and disassemble for a different thinkness shim a number of times here too 

Great to see that you're back to being in the Sheed and Enjoying your time there     

Per

Yup.  Mike and I have certainly been jawing over this, and thus far I find this method of crank build to be a great way to get it done.   My 917 crank is very similar to Mikes....and I had the comfort of knowing that if each operation was carried out well, it would be successful.... unlike the unknown distortion you get from a billet crank, or brazed/welded crank.

[steamer]

Mike,

This build is stunning!!!   and I am so excited and thankful to watch this grow!....

Dave

[petertha]

In my design, there is a 20 thou gap between the crankpin ends (marked by the red crosses) NOT as shown in the illustration. This gap ensures the two crankpin end faces do not touch and so do not interfere with the alignment provided by the precision ground ball bearing inners.
Mike

Thanks for your patience with all my dumb questions.
- so the resultant squareness & length of each progressive CS throw segment is entirely controlled by the (I'll call them) flush crankpin rings like so?
- what material did you choose for rings? Hardened?
- maybe you mentioned grinding them or otherwise tweaking them if required? If so was that done on surface grinder or could this be done by lapping? I guess I'm wondering out loud what sort of alteration amount would be expected
- your connecting rods have bearings which is really the magic of this assembly, but do you see any reason why this CS buildup method could not be used for plain bearing/bushing style of rod?

[steamer]

In my design, there is a 20 thou gap between the crankpin ends (marked by the red crosses) NOT as shown in the illustration. This gap ensures the two crankpin end faces do not touch and so do not interfere with the alignment provided by the precision ground ball bearing inners.
Mike

Thanks for your patience with all my dumb questions.
- so the resultant squareness & length of each progressive CS throw segment is entirely controlled by the (I'll call them) flush crankpin rings like so?
- what material did you choose for rings? Hardened?
- maybe you mentioned grinding them or otherwise tweaking them if required? If so was that done on surface grinder or could this be done by lapping? I guess I'm wondering out loud what sort of alteration amount would be expected
- your connecting rods have bearings which is really the magic of this assembly, but do you see any reason why this CS buildup method could not be used for plain bearing/bushing style of rod?

As I recall from our discussions and the concept models like the one shown, that is an off the shelf roller bearing inner race that was available from the usual industrial hardware outlets.

[Vixen]

In my design, there is a 20 thou gap between the crankpin ends (marked by the red crosses) NOT as shown in the illustration. This gap ensures the two crankpin end faces do not touch and so do not interfere with the alignment provided by the precision ground ball bearing inners.
Mike

Thanks for your patience with all my dumb questions.
- so the resultant squareness & length of each progressive CS throw segment is entirely controlled by the (I'll call them) flush crankpin rings like so?
- what material did you choose for rings? Hardened?
- maybe you mentioned grinding them or otherwise tweaking them if required? If so was that done on surface grinder or could this be done by lapping? I guess I'm wondering out loud what sort of alteration amount would be expected
- your connecting rods have bearings which is really the magic of this assembly, but do you see any reason why this CS buildup method could not be used for plain bearing/bushing style of rod?

As I recall from our discussions and the concept models like the one shown, that is an off the shelf roller bearing inner race that was available from the usual industrial hardware outlets.

That's correct Dave. The illustration petertha keeps referring to is only one of many concepts we looked at, unfortunately it was the only one I could find. The hardened roller bearing inner, shown in the illustration, would be ideal for use with a plain bearing/bushing solid conrod.

The design I used for the W165 looks more like this. You can see how the crankshaft segments fit tightly into the ball races and the gaps between them. You can also see the shim washer between the two conrod bearings.
Only the locking bolts are shown, the dowel pins have been omitted for clarity (I think?)



Hope this helps

Mike

[steamer]

Yup   as I recall we had several concept layouts going back and forth.     I really like where you ended up!

Dave