[quote=briandownunda;1720311]Hi, I am a new member of this forum. I have just purchased a 1987 560SL with 94k well documented miles on it. The timing chain, rail, tensioner, and tensioner rail were replaced at 85k miles, about 2 years ago. I bought the vehicle knowing that it has a mechanical problem. It runs very rough & has a fairly loud tapping sound. The seller chose not to have the vehicle repaired.

When you first start the car is there any blue smoke, your problem sounds like bad valve seal leaking oil into cylinder... As far as tapping sound that might be a valve that is hanging up do to deposits. the 5.6 engines do this I have found out with my 560 if I run shell v power or Bp it cleared up my valve tapping.. I would start there with mileage on the engine an the work that was done what I have mentioned sounds more like the problem.. these engines are strong especially the bottom end.. I just replace valve seals at 135k that stopped one spark plug from fouling.. my oil consumption prior the job was a quart about 1k miles I have 8k on the valve seal job an no oil consumption try these first see if that solves your problem
Bob