Comment by zeusk
5 years ago
Any race or high power engine, especially those that rev quite high will need rebuild - not just in bottom end but often with piston rings and valves as well.
You don't really hear about those other engines much because their buyers understand that a race engine needs more maintenance than any other road car.
Also, not beating on the engine until oil has warmed up to temp will elongate the bearing lifespan quite a bit. I have a friend with E60 6mt S85 that has factory bearings at 110k mi and has perfect oil analysis results.
The S65 and S85 are road car engines, not racecar engines. They're also hardly BMW's highest performing motors. Even Dinan built engines don't suffer from that problem.
They're meant to be dual duty. There aren't any road car engines I'm aware of that use individual throttle bodies or 12+ compression without direct injection.
The S54 engine which came before the S65/85, was also high revving, had 11.5:1 compression ratio and didn't have any of the rod bearing issues. The 20v Toyota 4AGE also had them too with a high compression ratio.
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> Also, not beating on the engine until oil has warmed up to temp will elongate the bearing lifespan quite a bit.
I am curious if there is proof to this. I've always felt the same way. I know in the "old days" with iron pistons, if you you simply started up a cold motor and and drove it hard without a warm up period, the pistons would expand quicker than the block and would start to scour the walls and/or lock up.
But other than that, the only other "proof" I have is from people in high school that like clock work at 3:30 everyday, would smoke tires leaving the parking lot everyday. They seemed to go through motors every 6 months. I'm talking knocking bearings and lifters cracked in half. I've never gotten rough with anything I own until after a 20 minute "warm up" and all has been well (so far).
It wasn't so much locking up or anything but cast vs. forged.