I'm reaching the endpoint on the refurbishing of this old 1969 280SEL so when I noticed that it seemed to lag a little at low RPM I decided to check the plugs and then advance the timing a bit. All the plugs checked out except #4 which was a little wet. I then advanced the timing 4 degrees or so and test drove it. The difference was amazing. Lots of pep and good acceleration. I think I'll get a hotter plug for cylinder #4 just so it stays clean. What would be a good Bosch replacement for the W7 DC that I'm using right now? Any ideas out there? Thanks all.
Thom

Thom,

On my 190SL I went to a NGK BP5 from a BP6. I believe that the BP6 is the equivalent of the Bosch you are using. Be aware, however, that a hotter plug may result in early detonation (a bad thing). However, you may have a different problem. I'd be concerned that #4 isn't firing all the time. Might want to check out your ignition, and look at putting in an electronic ignition.

Thanks. Just as you were responding to this question I submitted a new thread. I'd like to see what the others might think about this. Cylinder #4 is definitely working so I don't want to do anything rash here. Ahhh, perhaps it just needs a valve adjustment.
Thom