Ignition timing

Thank You,
Honestly you guys were fantastic. Yes I am starting to think that I need to get prepared for the inevitable day (sooner than later) that I need to refurbish the Trigger Points. 1 more question if I may. The service manual states that for a 1973 Mercedes 450 the timing need to be at 5 Degrees ATDC but a lot of people I have been talking to state it should be BTDC (I have it set at 750 rpm, 2 degrees BTDC with a dwell of 28 degrees - supposed to be 30 - 34 but finding hard to adjust to this). The car is surging a little at idle by app. 25 rpm but this could be another issue - possibly T/P's?? It also has an ignition module next to the coil but it is not connected at the bottom so I'm not sure what it does.
Anyway, what is you opinion of the timing mark?
Regards
Peter

Hi Peter,

as we are now talking igntion and no more trigger points, I have moved the subject.

Regarding your ignition timing, it depends on your ignition distributor. You will find infos here under 107 SL workshop manual .in chapter 07.5-500 . Read your distributror no and check there. First adjust dwell, then timing. And do not forget that it needs adjusting and verifying at 1500/min, 3000/min and of vacuum adjustment!

Will do and great reference list.
Thanks You!

Ive got a 1974 450SL and I’ve got my timing dialed in at 30degrees btdc without vacuum. Which ends up being tdc +-2degrees with vacuum line. I’ve been told to keep the vacuum line disconnected and plugged. But it ran a little sluggish at times. So could I keep it timed to 30degrees btdc without vacuum and connect the vacuum line to achieve tdc+-2degrees?

Although my distributor isn’t listed there. Mine anppears in the national version ands ends in 403 007. The standard version for m117 doesn’t show my distributor. Job 7.5-500

Hi Unknown,

please sign ur messages so that we need not guess ur firstname and can greet u.

Your ignition distributor is mentioned in 07.5-500 in chapter B country version US. It shall have 18-22° BTDC at 3000/min with vacuum. And it shall achieve 5° ATDC with vacuum at idle. 

Ur ignition distributor has double vacuum box for advance and retard and it has 2 levels of rpm adjustment. Pay attentin not to mix advance and retard vacuum line,