Quote:
Originally Posted by Mani59
And here is Part 3 of Project Frankfurt (E92 M3). 
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Pretty clear what happened there: the first main bearing spun, because s65. Owner kept driving, as it deteriorated further and further... That bearing got so loose that the nose of the crank started to flex a lot. This probably caused a lot of wear on 1 and 5 rod bearings, and destroyed the front main seal...but the owner kept driving. Eventually the front main bearing got so loose that the flex was enough to break the crank. Only then did the driver take notice. I bet it was driven for hundreds of miles, eating the front main bearing, before the crank snapped. Heat doesn't really factor in the crank failure at all, though for sure there would have been a fair bit generated. Special.