Originally Posted by DLSJ5
True, but how does one really tell if the excessive wear is oil starvation from a possible tight clearance issue or from too thick an oil?
Does it have to be restricted to just two options?
I can't see how either or both of these alone can account for the wear patterns that can be seen in quite a number of bearing sets from S65 (and S85) engines.
Low wear on the bottom bearing.
Excessive wear aligned with high combustion stroke load on the top bearing.
One or two rod bearing sets having far more wear than the rest.
What might be interesting: next time someone pulls apart their engine for a rod bearing change and finds one or two bearing sets with far more wear than the others, would be to check the ECU logs for reports of a much higher number of misfires in those cylinders compared to the rest.