I had a motor do the tighten-up, and it seems the rod bearings are "scorched". No culprit identified so far, only a list of suspects including a warped oil-pump shaft.The motor is off for repair, but I don't want one event to lead to a repeat performance. I have pulled the access panels off the bellhousing / sump tank of the DB-1, and didn't find any trash, like Mike Allison's famous motor-killing oil can cap-liner. It was recommended I flush the sump tank with gas or brake clean. Any thoughts or recommendations? Anything else that needs doing?