Originally Posted by Zackbo
I understand the importance of cleaning and/or replacing the oil pump, oil cooler, etc. when rebuilding a motor with a spun rod bearing, but the fact is almost all spun rod bearings are due to incorrect clearance, heat expansion, or oil starvation; not a piece of debris in the oil getting in between the clearance area
. Flame suit on, but it's just a fact.
I've taken apart a many a spun rod bearing motor, ones that were ran a good while after the initial failure. The other surviving bearings did have scuff marks from the debris in the oil, but none ever spun due to the debris.
the VERY VAST MAJORITY of spun bearings comes from metal to metal contact due to the WRONG OIL BEING USED
this wrong oil shears piss thin and is consumed by the engine through the pcv system...THIS causes knock....the knock then pushes the metal parts together through the sheared oil film in the bearings..
and p0p goes the bearing
the MORAL of this story is this:
USE GOOD OIL THAT WONT SHEAR AND BE CONSUMED AND YOUR ENGINE WILL LAST A LOT LONGER