Should I use/replace this main bearing?

[PhilBeans]

I ordered a single white main bearing pair for my E30. Upon inspection, I discovered one half has a very small nick in it - I can just feel it with my nail.

These will be going into my (semi) daily drive (when I get some spare time to put it back together).

What do you reckon? Safe to use, or should I just get another? The parts came from the US, so returning it is not really an option.



(Just to clarify, I will not be rebuilding my engine based solely on the yes/no responses I get to this post - just trying to get a sense of if it's a good idea or not )

[Rav335uk]

IS it stood proud or is it sunk into the bearing??

If the later, I would use it, as it won't scratch the crank.

[jimbom30cab]

I'd agree with Rav

The bearings work by building up a hydrodynamic oil wedge which actually seperates the bearing shell from the journal by a thin oil wedge. The shaft is acutally slightly undersize to promote this wedge. Therefore if you have a small nick in the surface which is not proud at all then i will not effect the wedge and the lubrication will be fine. Any raised part to the nick at all even a thousanth of an inch will lead to damage to the bearing, it might run ok but it will effect the lubrication and shorten the life of that bearing.

[DanThe]

Regardless of it being an indent or not I wouldnt be fitting that until its had a bearing scraper over it.
Most impact marks will have raised edges, even if you cant feel them