Originally Posted by dhaghighi

Also....have faith that your chain is fine!
These cars have timing chains for a reason. And the engineering has been refined over 60 years of mercedes advancement. Unless your engine has over 300k on the clock, chain stretch is probably not your problem.
Basically, the chains dont stretch unless they are improperly tensioned.

A good Mercedes mechanic who knows the M104 would take an hour to pull the top cover and inspect the timing. The dowel holes should both align with the top surface of the head. If they do not, one of them is one tooth off.

So dont even worry about the crank at first. Diagnose your problem by checking the cam dowel holes relative each other.

If they do align, then you move-on to the crank and check where the OIT is relative to the marker on the left of the sensor hole. If it is off by more than 1.5-2 cm either direction, you are one tooth off on the crank.

So once you remove the top cover and isolate the problem, you can detemine the amount of work you are in-for.....