Spark Plug

Ricks70Duster340 said

I am certainly not against increasing the cruise timing, but am very concerned about over-timing causing problems. As I've recently read (from another poster) someone ended up with engine damage from over-timing and he reported that he could not hear any detonation.

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Certainly detonation can happen with too much timing. And it will kill parts.

At low load, part throttle the engine will take more timing. How much more timing and when it occurs has to be tested to know for sure.

What I'm sure of is a quick curve and vacuum advance don't usually play well together.

At and around peak torque is where you run into big detonation issues. Lets say you make peak torque at 4500 and peak power at 6000. Then bring the timing all in by 3000. Unless the timing is retarded a bunch all that timing below peak torque is killing power.

If you then add vacuum advance and you add all that timing at peak torque you kill even more power and if you aren't into detonation you are very close.

If you keep the timing reasonable around peak torque chances are you won't have enough timing at peak power so you lose power there because you can't add any more timing without getting into detonation or you are already detonating and its now worse.

Saying all that, you need to correct the curve so that at WOT and peak torque you have the proper amount of timing so you can add vacuum advance.