Camshaft, damaged or not? - BMW Forum

benhanson · 02-19-2007, 04:06 AM

I'm rebuilding an M42 engine out of a '91 318i, and unfortunately I removed the camshaft without reading the Bentley. As far as I can tell, the M42 has solid cams and thus probably aren't prone to breakage as the hollow ones are, but I'm still left wondering if any damage was done. Does anyone know what I would need to inspect thoroughly before deeming the cams and bearing ledges to be OK?

Starmavin · 02-19-2007, 05:20 PM

Take it to a machine shop, have them check it and do a magnaflux on it if you are worried about cracks.

benhanson · 02-19-2007, 05:37 PM

So the damage would only be to the camshaft, not the bearing ledge?

Starmavin · 02-19-2007, 06:02 PM

What happened exactly? You removed all the bearing caps?

benhanson · 02-19-2007, 06:07 PM

I removed all of the bearing caps. I wasn't aware at the time that a special tool was required, so I pretty much just broke all of the bolts, then whizzed them off with an electric screwdriver. The cams show no visible damage, though I'll likely take your suggestion and have them checked for straightness and cracks. My big concern was whether there was the potential for the ledges to be damaged, due to the uneven lifting of the cam(from valve pressure) during removal.

This is the first time I've torn down a engine without rocker arms, so I wasn't really thinking.

Starmavin · 02-20-2007, 06:54 AM

The largest worry is that the bearing caps get mixed up, the ledges can be cleaned up with a file to smooth out small burs that may stop the cap from mating with the head completely. The bearing surface of the cap is the most critical part not to have damaged.

But how did you break all the bolts?