Craig:

MBDoc has mentioned a .040 gap for M103 motors. The book calls for .032. On the flip side, Gilly once commented that .032 was the correct gap and I detected in his post that he believed in the factory spec.

I'm just a diyer, but have used a "half way" approach in my M103 motor, that being a .036 gap. I get a slightly smoother idle and 22 mph using 93 octane if I drive 65mph-70mph.

Whatever works I suppose.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"