Running rough is not a good sign.
There no real percise way to time those motors unless you want to go crazy with a degree wheel. It's amazing to me that you simply line up the dots on the cams and the crank pulley and off you go.
That said, your timing might be off a bit, but from my understanding there is not much room for error. Pull the valve cover and check the alignment of the cams and crank markers. Is everything still lined up??? You didn't rotate the motor at all with the chain and cams unhooked??? It is possible to damage a valve by doing that if you encountered some resistance and continued. Does it smooth out once off idle? Rotate the motor with the valve cover off and watch the chain. Any high marks or strange shiney wear marks? You crimped the chain correctly? Mine also makes a strange tapping noise occasionally.
If everything lines up, do a leak down or compression check to insure the cylinders are sealing. Check the plugs when they are out. Is one of them wet??
If it passes these tests I would look for vacuum leaks. I read that Benz recommends replacing all sprockets on the higher mileage motors if they show signs of wear. I would bet your are ok, but it is something else to look at.
Just my free $0.02.
Last edited by Tinker; 07-15-2003 at 03:54 PM.