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

[kvom]

I've been away traveling for 3 weeks.  Great update to come back to.   

[Vixen]

Welcome back kvom

Dave  I drew up at least six alternatives before I settled on option 3.
Several of the rejected options used a hardened steel sleeve: can you recall any of "the usual industrial hardware outlets" for the  'off the shelf roller bearing inner race'?



Cheers

Mike

[steamer]

Welcome back kvom

Dave  I drew up at least six alternatives before I settled on option 3.
Several of the rejected options used a hardened steel sleeve: can you recall any of "the usual industrial hardware outlets" for the  'off the shelf roller bearing inner race'?



Cheers

Mike

Yes    McMaster Carr   Here's the link    They are known as shaft liners

https://www.mcmaster.com/roller-bearings/shaft-liners-for-precision-needle-roller-bearings/

Dave

[steamer]

As I recall, and I've had a few variations on a theme for my crank, that these liners were a bit long, and that it might have been a requirement to shorten them for either of us to use them,     

Dave

[Vixen]

Thanks Dave,

When you know how they are described, it's easier to find a supplier.

For those of us over this side of the pond; try 'Simplybearings.co.uk' and search for 'needle roller inner rings' Plenty of sizes and lengths to choose from; at affordable prices.

These inner rings will allow you to do a Schilling style, built up crankshaft, and use plain bearing/bushes in the conrods, when there is insufficient room for a roller bearing.

Alternatively, you could use a pressed in, hardened, solid pin, As Steamer did so successfully, with his superb Porsche 917

Cheers

Mike

[steamer]

Thanks Dave,

When you know how they are described, it's easier to find a supplier.

For those of us over this side of the pond; try 'Simplybearings.co.uk' and search for 'needle roller inner rings' Plenty of sizes and lengths to choose from; at affordable prices.

These inner rings will allow you to do a Schilling style, built up crankshaft, and use plain bearing/bushes in the conrods, when there is insufficient room for a roller bearing.

Cheers

Mike

I went with hardened crank pins made from ground A2 steel rod, cut to length and then heat treated and tempered..   I did this because the available room on the 917 crankcase was quite narrow, and prototypical rods were requred with plain bearings.    Those of you who want to know how mine was constructed can head over to that thread, I won't sully this fine one with that!   Love the explaination drawing Mike! 

[cnr6400]

Just an FYI - One other possible source for hollow cylinders for crank pins in this type of built up crank - the humble drill bushing, as used in production machining fixtures to guide twist drills. The bsuhings are very hard steel usually and are made very accurately inside and out, and are available in a huge variety of sizes. McMaster Carr link to a page of metric ones is below. Inch sizes also available in a huge variety. Some are available in stainless steel should you need that.

https://www.mcmaster.com/drill-bushings/metric-press-fit-drill-bushings-9/

 

[Vixen]

Thanks for the additional info cnr6400, it may help someone else following down the Schillings built up crankshaft route.

I just wish we had access to McMaster Carr from this side of the pond

Cheers

Mike

[cnr6400]

Yep, McMaster Carr is a great resource. There may be a UK based drill bushing supplier, might be worth a Google search for jig and fixture components, toolroom supplies, or just drill bushings UK. 

[wirralcnc]

https://www.boneham.co.uk/drill-bushes/
Try these. Used these several times for work. Fast delivery reasonably priced.

[Vixen]

Some details of my Schilling, built-up, Crankshaft

Thank you all, Steamer, cnr6400 and wirralcnc for the information on drill bushes and shaft liners. This information may be use to someone else who may be considering the Schilling built-up crankshaft route.

For my W165 engine, I am using roller mains and roller big-ends just like the original engine. So I do not actually need drill bushes or shaft liners, (although I did once consider a different crankshaft construction which could have used them). However the information you kindly provided may be of use to other multi cylinder engine builders.

This is the crankshaft construction I used for the W165



Thanks again

Mike

[Vixen]

We got a bit sidetracked there with drill bushes and shaft liners as neither Steamer or I use them.

So back to the plot. I have completed a trial assembly of the second crankshaft to ensure everything fits. It does, so the second crankshaft can be set asside for a while. I will take it apart again over the winter, when it's too cold to go outside to the shed, give it a final polish and then assemble it into the second engine.

Here is the crankshaft laid out with all it's individual parts flying in close formation. There are 44 parts laid out on that table.






Then, ten minutes later, the whole crankshaft has been all bolted together.








And of course, Crash wanted to get in there for a closer look




The Mercedes Benz W165, was in 1939, very much a 'state of the art' racing engine. Most racing engines of the 1930's era used roller bearings for both the main and conrod bearings. The were expensive to produce. The big end bearings tended to be quite large and bulky, therefore needed larger counterweights, which in turn needed a larger, bulkier, crankcase to contain the rotating parts.

'Thin wall' shell bearing came of age during the 1940/1950's and have have since become the norm for both domestic road and racing cars. The use of these high performance plain bearings allows for more compact bottom end design. You can see from the excellent Porsche 917 (1968) being built by Steamer, just how much the 'state of the art'  developed over the intervening 30 years.


Now the two crankshafts are done, I need to think about whats next.

Cheers

Mike

[cnr6400]

Great work Mike! 

[crueby]

Thats a great view with all the parts laid out like that!   

[RReid]

Thanks for that series of photos, Mike. Seeing the parts all laid out like that, following by the assembled shots, makes the whole deal so much easier to understand than staring at drawings, no matter how well done. Besides, the finished assembly is just so pretty! I also very much enjoy the bits of background history and context.