Don't know enough about aircraft to advise, just like to play around with engines.

Motorcycles were originally my passion, but now I'm not able to throw a leg over one, and these things interest me a lot, and they still fit in with my engineering trade.

I'd say that your engine has needle rollers, and so will possibly need to be stripped and fitted with a thrust bearing of some sort. I keep saying that I will check out the engine I have tucked away, but didn't find the time this weekend, - maybe tomorrow! , then I'll have more of an idea just what I'm talking about!

Please bear with me, I've got some other pressing business to deal with, and get it out of the way.