We received an engine bare block in today for a crankshaft conversion/rebabbitt.
Since it was done by "others" I zealously inspected all portions of the engine block to see what the other shop did or didn't do;mostly didn't.
Other than missing many cracks and poor valve job I noticed the babbitt torn up on the mains.
After looking closely with my magnifier I came to conclusion it was glass bead contamination. pieces of "dirt" iron/brass embedded into the babbitt. The dirt also traveled to the cylinders where there're heavy scratches in the bottoms of all cylinders.
Which raises a flag for all you do it yourself'ers out there.
You can never be to clean this is the result of a dirty job.!
This engine has 1200 Miles on it.
Also happens when a 'fresh' short block is fitted with the old dirty tranny and crankcase.
That motor with 1200 miles should have had several oil changes to allow such 'dirt' to be expelled too .
But clean first and clean assembly may be a chore but one that is a must .
You know it says something about the times we live in when a supposedly reputable shop would leave that crap inside a block. What the hell did they think would happen?
Good info, thanks - also I have seen antique motorcycle engines with the same problem, After being rebuilt.