MG Car Repair: Help with timing., tdc mark, vacuum advance

Question
Its Jon with the 76 Midget (1275 motor in it). So, the degree pointers are
non-existent on this car. Not sure why they are gone, but heres what I have
done. I did find TDC with a coat hanger--made a mark on the pulley with
white paint and one across on timing cover so that I could check the timing-
-began using an advance gun. I forgot to disconnect "vac hose" from the
distributor and plug, so timing looked really advanced. Silly me. I also
thought the vacuum advance/retard was all I needed to set timing. I then
read my manual. Plugged the vacuum hose and adjusted by moving
distributor. The timing was dead on at 13 degrees from before. However, the
vacuum advance is now wonky  since I was playing with it so much. How can I
get this back to a normal setting?

I, after getting this done, will turn to the carbs. The car sputters still under
load (on the road in gears--not with revving at a stand still) and my plugs
are all black sooty.

Thanks. Jon-George

Answer
Jon, you should set the timing statically, then the advances are not in play. If you have set marks for TDC, you can make 5 degree marks about 3/16ths inch from the TDC mark. Factory timing was for the engine when it was new and for what ever type of gas they had at the time they made the decisions what to set it at. So really the correct timing for any engine is different for each engine as long as you don't go into detonation. The most power and best efficiency is just before detonation. Many new cars today have a system that advances the timing until it reaches detonation then backs the timing off a little and and continues to do that. The most advanced systems now can advance the timing on each cylinder individually to get the most out of each cylinder instead of using the lowest denominator (worst cylinder). Some old mechanics would set the timing by advancing the timing and open the throttle quickly from idle and continue to advance the timing until they hear detonation. (valve rattle as it was called or pinging) then they would back the timing off until it would not ping. The only fault with that method is that sometimes it would still go into detonation at high RPM and detonation is very hard to hear at high RPM and damage to the pistons will result. This is what all competition engine builders face.

That may be more than you wanted to hear but with no factory timing marks that is what you are facing.

If you mean that your plugs are flat black then that means it is too rich (choke on a little or flooding or jets set too rich.

If they are a glossy black then that could be oil burning.

Howard