Quote:
Originally Posted by nick3753
I’m curious, at what mileage does one start thinking about an “engine rebuild”?
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Zirra hit the nail on the head. This is a wildly subjective topic where in order to give a remotely reasonable answer, you’d have to know the entirety of the car’s history to an impossible degree.
We have an engine in the shop that spun a main bearing at 60k miles with 20k miles on the rod bearings, in the best condition I’ve ever seen a used motor (aside from the spun main bearing obviously) which came out of a car that had a perfect maintenance history and is a single owner car, which is also nearly flawless. On the other hand, we recently received a running core that (and I’m not at all joking here) had the drain pan on the oil plug welded shut because the owner had stripped the threads. 190k miles of obscene neglect lol.
My M3 has 180 on the clock now? Maybe more… I don’t pay attention to it. I daily drive it from my house next to VIR to the shop, approximately 30 minutes each way, and there’s not a single time I drive the car where it doesn’t see 8000+ RPM. Last year I did 8 track days with it, full send the whole time. Original motor. Mine too was a meticulously maintained single owner car before I bought it at 150ish thousand miles. At our last track day in October, my brother’s m3 with 200k miles seized up on the back straight as he passed bitch. Scattering pistons across the track. Kitty litter is expensive lol.
My point being, there doesn’t seem to be a simple recipe for success. We’ve identified a major issue regarding the oiling system that is a symptom of a handful of causal factors. We’ve not done enough testing to speak to it definitively, so I cannot go into specifics on it at the moment, but simply doing rod bearings is entirely insufficient. All of the blown motors we’ve received in the last 2 years have had front main bearings welded to the crank and aftermarket rod bearings in pristine condition (except for 1/5, typically). This could be survivorship bias, or it could be a pattern. Once we complete more research, we’ll likely put out a paper on the topic outlining everything we’ve found, how we came to our conclusions, and what the ultimate solution is.