P6 thrust bearing dodged a bullet…

[87cr250r]

An important characteristic of a plain bearing is galling resistance which aluminum does not have. Brass isn't so great either. Aluminum bronze would be a better choice. Plastics can work very well as they're able to be embedded with lubricants and are inherently resistant to galling. Plastics such as Nylon 4/6 can exhibit very long life as engine bearings. The Euros like Nylon 6/6 which is why their timing chain guides fail.

It doesn't have to be softer to make a good bearing.

This document is geared towards stainless steel bearings but the concepts are broadly applicable.

https://nickelinstitute.org/media/1780/reviewofwearandgallingcharacteristicsofstainlesssteel_9006_.pdf

 

[ckouba]

Yep, Aluminum… Whats it going to do, void the warranty the Allison part looks like a fiber re-enforced thermoplastic, probably popped out of a injection mold machine run by Chinese slave labor for .50 each…

...As for dimensions, well Allison was kind enough to provide the new bushing thickness, 8.5mm or .335”, in the second bulletin. Also that it is 4.9mm thicker than the original which was ~3.5m…. The roller bearing is 1.992ID and 2.862 OD, but I am machining the bush to a slightly larger OD as the races it sets upon appear to be 2.920.

So a donut 0.335" thick with an ID of 1.992" and OD of 2.920" of "soft-ish" alu or plastic is all that's needed?

 

[Ronmar]

If it were a constantly loaded application I would not do it this way, but with the abundance of lubrication flow and only casual contact that i can see, I think it will work well... the way the oil flows it may actually work to hydraulically push the carrier away from the bushing whenever they do come into contact as that is the only path for oil to exit the center tower against the rear face of the center clutch carrier...

 

[Ronmar]

So a donut 0.335" thick with an ID of 1.992" and OD of 2.920" of "soft-ish" alu or plastic is all that's needed?

in this case i think so, as long as the "plastic" is up to the chemical and thermal tasks, like I suspect the Allison component is...