#4 Bore for Main Bearing Pitting

[martianman1999]

Inspecting case for rebuild and all measurements check out within spec for .020 line bore and .040 thrust cut. On the bore for bearing #4 there is some pitting at about 10 o’clock. The measurements are within spec when checking the area. It doesn’t feel like anything is proud and in the pits it looks much darker than the rest of the area. Could this have been there from before the line bore?

This engine ran when I tore it down, it was new to me and condition was unknown. After disassembly other than this one issue with #4 the only other issue was some light oil burning from worn rings. I was planning on rebuilding as a 1800 but if this bore is questionable would putting it back as a 1600 be acceptable?

[modok]

If it measures good, then it is good.

[martianman1999]

Thank you very much