I'd like to hear some knowledgable opinions. I just know enough to be dangerous, and on that basis... sounds like a bad idea? There is supposed to be some embedibility on a bearing to the best of my knowledge, so any small particle that gets in there can get buried and doesn't scratch the crank. And having a bearing polishing the crank while the car is running? Also sounds like a bad plan to me... I want to keep wear to a minimum! Keep those clearances where they were originally set if at all possible! Plus polishing implies that there is metal to metal to contact, and there should not be any (between the crank and the bearings) in a running engine unless something is wrong. But that's my uneducated opinion.