What could this be?
I don't know why you'd want to replace the cam if all that happened was that the metal dowel fell out. If you've retrieved the dowel from the oil pan, and it doesn't look like it's been chewed up too bad, I'd say consider yourself lucky. Drive it, and forget about it. The alignment dowel is only there to make sure you orient the cam properly for TDC. If the cam hasn't been taken out, I say stop worrying about it, and drive.
Anyhow, if this is a dowel necessary for cam alignment on an install, and I'm about to put a new cam in there, how do I get that dowel back in place?

