I tore apart my engine over the weekend because cylinder 8 had eaten the air cleaner stud. https://www.thirdgen.org/forums/tech...r-stud-vs.html It appears that a few small particles from the bolt were able to make their way into a main and a rod bearing. All of the journals mic out to within spec but they both have a score around them. It does not catch your finger nail but you can feel it with your finger nail. You cannot feel it with your finger, well I can't. You can see it. The entire rotating assembly and block had 2,000 miles on the clock. Am I OK with simply replacing the bearings or do I need the crank ground on those journals?

Hi Tibo ,

Standard wisdom is that both sides of any "wearing pair" must be renewed together . I know of no instance where it would be considered acceptable practice to change the bearing shells without providing them a likewise brand new surface to break in to and with .

Not quite sure we are on the same page, I would be replacing all of the bearings on the crank, not just half of a main and half of a rod. Would it be acceptable to polish the journal with Emery cloth if it just needs a "fresh" surface?

Take the crank to a shop, and see if polishing it is an option

I would have a shop look at it and possibly clean the block. Could have more particles in the oil passages and have this happen again.

Its probably gonna need reground or polished. It may live without it but not the best way to deal with this problem. Atleast get a machine shops opinion

Hi Tibo , Sorry for not explaining myself better , but I was meaning "both sides of a wearing pair" to mean the crankshaft journal as one side and both bearing shells as the other side , the two surfaces riding together as being 2 shells = 1 bearing , riding on 1 journal .

And yes , I most certainly would have the surface of any journal renewed or at least inspected and dressed by a competent automotive machinist that I was replacing shells on . You gotta figure that by 2000 miles the wearing surfaces have fairly well "bedded in" and it could be considered fully "broken in" . The unique wear patterns of the breaking in process have been established on both the crank and shells by then , and this is the basis for my answer .

I took the crank to a machine shop, the owner felt confident that that journal and main bearing throw would clean up well enough without a grinding. Also took the block in the be sleeved and hot tanked with new cam bearings as I wasn't sure they were worth using again with everything already apart and in the shop.