M116 Eats Cams??? - PeachParts Mercedes-Benz Forum

Strife · #1 07-13-2009, 03:18 PM

When I purchased my 380SL at 95K miles, it made a terrible valvetrain noise and I purchased the car with repairing this priced in. As I thought, the rearmost lobe on the RH side was eaten, and the cam follower was severely grooved. This might have had something to do with the oiling tube so loose as to be easy to actually lift off of the cam towers.

I replaced the cam with a new aftermarket cam, and all new rockers. The oiling tubes were cleaned to surgical standards and fitted with new plastic fittings. Naturally, I used break-in lube. To be on the safe side I also replaced the hydraulic compensator for that valve with a new one. The shim looked a bit "polished", but still OK.

All seemed well on the 380SL,for 25K miles.

Before I owned it, this was obviously not an example of a "well-maintained" engine. When I change the oil every 3K miles (religiously), the oil looks old and the car may burn 1 quart every 1-1.5K miles, not great, but not unreasonable at 130K miles. There is some blow-by. My 560SL leaks, not burns, and at 3K oil changes (on a 108K engine), the oil looks almost as good as when it went in.

Anyway, all seemed well on the 380SL.for 25K miles, although there were a few surprises along the way - but nothing from the RH head. Until now. I took the RH side apart, and basically, the same thing happened again, although I obviously caught it much sooner. The cam looks only a little "gouged" on the lobe tip, and the follower is not nearly as bad (but still unacceptable).

I really don't want to replace the cam again. I actually would be willing to do it if I found a good used one (if possible) but I would worry about pushing my luck with the cam tower bolts, which are of course really head bolts.

I have, however, planned on cleaning the oil tube (I do NOT think it is plugged), putting new fittings on, and replacing the rocker. I have the "normal" and next biggest shim size shims that I can install.

Questions:

1. Why does this always seem to happen on the 116? On the RH, and on the last cam lobe???
2. What are the ramifications of putting in the new rocker and the thicker shim? (5.1 to 5.45mm). Any guesses on how long this will last? 10 miles? 100? 1000? 10000? 100000? (ha ha).

Thanks