Oil Failure or Something elase? 385HP 454
 

The prot engine was replaced about 200 hours ago for a different reason, and the same engine is being replaced now. The first replacement was a Merc repower. at least this is what we think it is. Was bought from a Merc dealer and Merc techs put it in according to previous owner. Initial inspection shows signs of what resembles oil failure, or incorrect oil gap on bearings due to all bearings are scored.

Engine has a Mrcruiser Repower plate on the side
Head and Rocker stud bolts have what appears to be white silicone on the ends.
Heads look good with no signs of preignition, only one cylinder shows slight sign of rich fuel mix
Piston tops all look good
Some of the push rods were installed upside down

Problem areas:
Oil pan splash guard shows copper bits all over it
All connecting rod bearings have no copper showing, all show scoring
Rod bearing number 7 was spun on to it self
Did not remove main caps

The engine had 200 hours and had used Merc 25W40 synthetic blend and Merc filters.
The engine was a Merc repower so why did the bearings fail so soon? Assuming that since this was a Merc repower, or at least this is what we think it is, the engine was rebuilt correctly. The engine which replaced it is also a 2008 Merc repower, which was sitting in a Florida Dealer. Concerns now is what could have cause this to happen? Starting to think this engine should not have used the synthetic blend oil and maybe use what I use in my engines, non-synthetic straight 40W.

Any ideas?

I’m sure others will chime in, but it sounds like it could be a multitude of problems, none of which has to do with the actual oil you were using. I would bet on incorrect tolerances, machining, and or engine assembly work. Or a reused contaminated oil cooler??

Well of course it can't be the oil, its Merc oil. There is no way that could be the problem....:lolhit:

Did you take an oil sample?

It is not the oil, unless of course it is lack of oil due a pump failure of blockage in an oil galley.

Ken

No, didn't take a sample, has copper all through it.

I'm thinking the engine is not a Merc rebuild, it's probably a knock off. Someone took a Quicksilver reman tag off a motor and put it on this one. Going to go get the tag number and see what I can find out about it.

I doubt it really has something to do with the build from the beginning, brearing failures normally happen within first hour, I am going with some kind of pump/flow failure, or running oil too hot for too long, clogged cooler?

if it was builder error you would have never gotten 200 hours on them bearings.....