Quote:
Originally Posted by XMetal
Finn,
Good call on the bearings. I'm very surprise to see how bad our bearings are compared to E46M3s with similar miles. Our engines are supposed to be the latest and greatest iterations, but data show otherwise. What bearings did you end up going with?
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WPC treated. There's no definitive answer on those vs. BE and so many variables that it's rather moot IMO. The true fix is to regrind the crank and expand the journals. But if I recall the cost of that it's the equivalent of three bearing replacements.
Your point is well taken on ours vs. the E46. These are out of my Z3M (new acquisition) with 84k miles. (Did this and the subframe upon purchase.) Worn, but, there's 2x the miles of the Z4M bearings in the post above and 25 track days on these.
My developing theory is after the initial S54 bearing debacle sourcing of bearings and downstream processes were tightly controlled. (Clearly there are intrinsic design issues, but that wouldn't explain the model specific longevity differences.) That may have diminished with time and/or stocking levels of bearings, or with the plant doing the assembly. Was the S54 of the Z4M assembled in Georgia or Germany?