Jumpy timing 3200+

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Jan 1, 2020 | 07:33 PM

hairyboxnoogle

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Jumpy timing 3200+

With the light on it, harmonic balancer is smooth as butter to 3200 then is ALL over the place, 10-15* each way jumping back and forth. Vacuum unhooked. Initial thought is chain, but 60k on it, did they use composite cam gears in 69? Same symptoms with two different distributors. Only other thing i can think is spark jump but the engine runs smoothly. Has msd 6al, isnt around 3200 where they drop to single spark?

Jan 1, 2020 | 08:10 PM

xlt4wd90

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From: SoCal

Did you try running without the MSD?

Jan 1, 2020 | 08:44 PM

hairyboxnoogle

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I want to say it did it before i put the msd on, and was jumpier in general, but dont quote me. No longer have the points dizzy to stick back in.

Jan 1, 2020 | 08:59 PM

hairyboxnoogle

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Might have answered my question from a thread on another board.

Quote:

tried or considered a different timing light? i`ve experienced the same problem but solved with another light.MSDs and some dial backs do not play well together. Consider the fact that MSD does not sell a dial back timing light, nor do they suggest the use of one.

Mine is in fact a digital with dial back feature, and not an expensive one at that. Guy is running a 6A having same problem i am, where its fine till ~3000 rpm and jumps around.