I REALLY appreciate the replies! I will do it!! I am understandably reluctant to dig into the motor if I dont have to. I will report my findings.dshealey said:My first guess would be that something in the chain tensioner or guides has failed. Not common by any means, but can happen on any chain driven valve system.
The tensioner is oil pressurized, with a spring to maintain some pressure on it when the engine is stopped. Possibly a clogged oil passage.
The guide rails basically never fail, regardless of BMW's unfathamable 36,000 mile replacement recommendation. However, it is certainly possible that one could break.
I would drain the oil and look for either plastic or metallic particles.
I did have a similar noise once, and it was the front exhaust flange broken, the weld had failed. You can check these by loosening the nuts holding the exhaust just enough to be able to pull the exhaust slightly out of the head, then trying to turn all four flanges. If one turns at all, it is broken and needs re-welding.
page 91 Clymer manual has a pic of the tensioner taken apart - long spring should have pushed "piston" back out so your evidence/feeling points there14wntr said:swapped out the bucket for a smaller one. It was a little too tight. Now it is in spec. The chain seemed loose and the other thing that stuck out as odd was the tensioner did not snap back when I pulled the drill bit out.