Does dizzy rotation affect the ignition timing?
 

I did a heat backdate on my 911 sc 1983 today, and had the unpleasant surprise afterwards to have a non firing car.

When I putted the left plate I had to unplug the ignition wire, and also left spark plug wires to have more room.
But the dizzy was definitely too close. So I have loosen the dizzy lock down fastener , rotated it and was able to adjust the plate.
So the dizzy was not at the same place.

After putting everything back, the car was not firing. Good ignition noise, good battery, but no start.

I checked the spark plug wire. Well adjusted, ignition wire is ok.

Any suggestion would be great.

Thank you

Mathieu

Rotating the dizzy is how you set the timing. Yours is now off and needs to be reset.

You need to get it back to where it was.

I would first check that you are getting spark to the distributor. Pull the fat coil wire and place it near the center of the distributor. Have a friend crank the engine. The spark should jump to the female terminal. If ok, get a timing light, plug your vacuum lines to the distributor and have a friend crank the engine. Dial it back in to where it should be.

I remember having the same type of issue with my heater backdate. No room.

Thanks a lot.
That's what I was expecting.......

Maybe a hopeless question:
I do have traces of the position of the distributor before rotation. If I am putting it back to this position, does the timing will be ok, or once it is off, everything has to be set from zero?

I had to try it... So rotate back the dizzy, to its original place, and the car started right away!
Maybe need to be rechecked, but other wise, sounds ok. :-)

Nice job. Borrow a timing light and dial it in according to the instructions on the underside of the engine lid.