erratic timing on 360

Yea, those Sun machines are pretty smooth operating, they can spin up a distributor pretty quickly. The machines are driven by an electric motor, no engine pules, no vibration, just a smooth rotation.

Now take a distributor maybe like the one you have, maybe a light spring and a heavy one pair together, typical performance minded. Usually the heavy spring fits loosely on its pins, and the lighter spring should be more taught on its bosses. Depending on your tuning you may or not want zero mechanical advance at idle OR mechanical advance just right off idle.

So while keeping this in mind, a lighter spring or one that is loose on the bosses can cause your timing to bump around. Especially on a cammed up hipo motor, just racing to get out of the garage. lol


To challenge this, take the lighter spring switch for a heavy one.... and check your timing.