912 Thrust main bearing broken
 

I pulled a customers 912 engine out yesterday to replace the flywheel seal and found that the rear main bearing behind the flywheel was broken. Have any of you ever seen this happen? I have seen spun rear mains and ones that have been pinched by the main bearing dowel pins but I have NEVER seen this. The crank is not broken either. The car came in running fine just leaking alot of oil.
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Dan

Looks like just the thrust flange broke off, Was there any shims under the flywheel? Maybe someone at one time cranked it down without shims and cracked it?

I have never seen this, Have seen bearings so loose they were chucking back and forth in the case which makes it hard to set the end play.

We used to abuse our VW engines ...a little.... LOL and @ high RPM they would break the crankshaft just behind the last main...always.. ! Now technically you have a P. Eng. but the characteristics might be the same,...?
You have a tougher crank and a tougher case but ??? just a guess

cgarr, There was a shim under the flywheel and the end play felt normal. If someone torqued the flywheel with "no" shims it would just make accessive end play. Possibly someone cranked it down with "too" many shims and crushed the bearing.

afterburn 549, The crank is NOT broken. I too have seen that many times in VW motors. All good ideas. Keep them coming.

I will know more I guess when the motor gets torn down. (that is if the customer wants us to go that far) He was talking about finding a good used motor instead.