Recently acquired a 1970 280 SL/8 (113.044 & 130.983 engine) with approx 145K miles. Compression is good in all cylinders and vehicle runs well (but rich). Service records indicate that cylinder head has been replaced at least twice and camshaft once, due to blown head gasket & overheating. Prior services have been performed by non-Mercedes techs (Shell service station!)

While inspecting valve clearances, noticed that when the cam timing notch is aligned with mark on cam support tower, crank timing reads 5-6 degrees ATDC.

Timing chain does not appear to be stretched (chain is taut over top of cam sprocket) nor is cam sprocket worn. Chain tensioner is functioning and there is no indication of chain slap at start-up. Eyeballing cam suggests that loosening chain and advancing 1 sprocket tooth would overcorrect problem. Crank timing disc and pointer appear to be correct for engine. M-B states that offset Woodruff keys are not available for this engine.

Any suggestions on how to rectify this problem? Thanks in advance!

JGL