Hello. My 1974 sailboat has a Volvo Pent MD11C that bit the biscuit after I bought her. (Against reasonable advice), I decided to have her rebuilt. Upon dis assembly they discovered that the connecting rod bolts had broken and twisted one of the connecting rods. Bought replacements & cylinder liners etc..) only to have the same problem occur again within 50 hours. Anyone have any advice as to what could be going on. had the mechanic check the crankshaft with a micrometer to check wear and was told it was OK. Any advice/insight would be greatly welcome.