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MG MGB Technical - Petronix and timing lights?

Now that the "Engine From Hell" is running, I was able to get a timing light on it. With the timing adjusted so that it idles well, I get 45 degrees of advance. Total timing at 3500rpm is 68 degees. No, the light is not adjustable for number of cylinders. Is it me or are these numbers not about twice what they should be?

Is the Petronix hostile to timing lights?

Pete.
Pete

If you have manifold vacuum advance to the distributor this must be disconnected and plugged at the manifold before timing. It is possible to get up to 50 degrees total advance when correctly adjusted (vacuum connected) and even higher when mal-adjusted. Did you confirm that your marks are at TDC when your piston is at the top of its stroke? Maybe your pulley harmonic balancer has delaminated and slipped round.

PaulH.
Paul Hunt

Pete, if it is your damper, here is the address of some guys in CA who can repair it for you. FYI.

Reconditioned Crankshaft Dampers
Damper Dudes
5509 Cedars Road #2
Redding, CA 96001
(530)244-7225
Bob Muenchausen

TDC seems pretty close. Must be the new light. I will try it on the other car and see what it reads. Funny thing is that the light also displays RPM and it is accurate.

Pete
Pete

I have a pertronix on my B/GT and I've never had a problem running my old dependable Sun Pro timing light, or (separate) dwell-tach with it.

If you decide to get a new harmonic balancer, paint a white stripe along the timng mark - and extend
the stripe across the front face of both the hub and pulley ring. This not only makes finding the timing
mark easier, it also provides an obvious visual indicator in case something should slip later down the
road.
Daniel Wong

Daniel. What a splendid idea. Thanks for mentioning it. Les
Les Bengtson

This thread was discussed between 08/11/2001 and 11/11/2001

MG MGB Technical index

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