[SnapCoupe]

Originally Posted by TZANIDO777

What else do you think it could be? I had a few credible people look and listen to it at the track (one of which builds engines for S54 race cars) and they all pointed the finger to a spun bearing given the noise the car was making at idle and the overheating on track.

Not discrediting you by any means, just curious what you're thinking it could also possibly be. Do not mind getting additional opinions. (I understand there are a lot of variables involved)

Also, what did you end up doing? Repair? Rebuild? Swap engine?

Pull your oil filter and shine a flash light at it. If its full of copper its more than likely the bearings. The only reason I mentioned it could've potentially been something else is mine was dead quiet when it happened. Also my knock was very faint and only noticeable when hovering the throttle at 2000-2500 RPM. The engine sounded totally normal at idle.

I ended up getting a new motor installed by the BMW dealer I work at after weighing all of my options and doing the math. I figured the car was worth keeping considering the money I had just put into it mod/maintenance wise, how its spec'd option wise, and the fact that my used motor options seemed to be a bit sketchy with what they came with.