You should have the cam timing checked. More than likely it is Ok because if it wasn't, the valves would bend.

My suggestion is as follws: Have the injection pump timing checked and set. The reason is someone may have adjusted it to compensate for the stretch and now the new chain is in. This will cause the injection timing to be off which is the same as ignition timing.

Good luck.

__________________
Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS