Ignition Timing 1968 911L 2.0l

[Gduplock]

Car has standard 2.0l engine running Weber carburettors, Bosch distributor with no vacuum advance.
I have been struggling for some time to get the engine running above 4000rpm, it's fine at lower revs apart from occassional popping on overrun. Played with timing and points gap and renewed ignition sevice parts to no avail.
User manual states plug gap 16 thou, dwell time 38 +/- 3 deg and static timing 0 deg BTDC. I've not been able to check dynamic timing at 6000 rpm, manual says 30 deg BTDC.

Yesterday as last resort set static timing around 10 deg BTDC (when measured accurately was in fact 8.5 deg). She now runs well up to red line (6300-6600 rpm) . There is still occasional popping on overrun.

Would you consider this normal operation or is there likely to be problem with worn distributor components?

I am planning to check dynamic advance up to 6000 rpm.

Your thoughts appreciated.

Graham

[stuby]

Are the carbs in good order ? Spindles worn perhaps ?

Stu

[Alan @ CanfordClassics]

Hi Graham, if you can now rev to 6k, dynamic check the timing and see what it is. There could be a fault with the dizzy, if you get stuck send it down and I will check it out (advance curve, phasing, etc) on our distributor test bench. Also check all the standard stuff, leads, points, fuel, fuel levels, plugs etc.

HTH

Alan