4G63 DEEP SCRATCHES ON ROD BEARING SHELLS

Hello.

Below i have attached pictures of my rod bearing shells with some scratches on them, i can feel them when i run my fingers across the shells. I installed the rods to the crankshaft to see if they are moving freely without hesitation before i go ahead and assemble the shortblock. I cleaned all the surfaces thoroughly and applied a generous coating of oil on the bearing shells. After i checked that the rods were spinning freely, i removed the rods and found these scratches on the bearing shells. I have polished them with the backside of emery cloth and some oil but this is the best i can get them to. Is this normal or do i have a problem here? Just to add, my oil clearances are fine, between 2.1-2.4 thou. Kindly advice,

Thank you

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I've never seen anything like that before. it looks like either the oil was very badly contaminated, it was assembled in the middle of a sand-storm (remember, you're working with clearances of little more than a thousandth of an inch, so ANY dust is going to be a problem), or the machinist 'polished' the journals with 60 grit emery tape. Absolute cleanliness is ESSENTIAL during engine builds, even dummy assemblies! Sorry, man, those are just fit for the recycling bin!

Can you post the shells as pairs and the crank jourmals?

Don't have access to the bearing shells right now but i will post them later. Here are the journals.

There does seem to be light scratching, especially #3, but most likely as a result, rather than cause, of the problem.

Hopefully others will give their thoughts, but to me it looks like either contaminated oil, or fine sand/grit from the atmosphere, introducing debris which has chewed the bearing surfaces up and marred the journals.