I'm in the process of rebuilding an M50 and discovered that the thrust bearing surface is broken off of the intake cam. I haven't seen any references to this online anywhere - any idea how this would have happened? For this to fail, I'd think that the cam would have to be pushed forward quite forcefully to fail like this, and the VANOS solenoid isn't really capable of doing that from what I can tell.
I found about a quarter of the thrust bearing that had broken off in one piece, but I think the rest made it down the oil drainback hole right under the E1 bearing cap. No beach marks on the cam, which seems to imply shock failure, however the cams are hardened and very brittle, so I suppose it could have been low cycle fatigue.
Thoughts? Fortunately I have a second set of cams lying around, but I'd like to avoid having this failure again.
I found about a quarter of the thrust bearing that had broken off in one piece, but I think the rest made it down the oil drainback hole right under the E1 bearing cap. No beach marks on the cam, which seems to imply shock failure, however the cams are hardened and very brittle, so I suppose it could have been low cycle fatigue.
Thoughts? Fortunately I have a second set of cams lying around, but I'd like to avoid having this failure again.
Comment