How does cam timing affect ignition timing?

How does cam timing affect ignition timing? In a short, two word answer... it doesn't.

I used to get questions from people asking things like: "My cam is advanced 4 degrees so where should I set my ignition timing at?" The answer is; Wherever your ignition timing is normally set at, or rather; wherever your engine likes it's timing to be at depending on your compression, fuel type, cylinder head material (cast iron vs. aluminum), etc. Cam timing has nothing to do with it.

Cam timing is VALVE timing. Ignition timing is SPARK timing. Just because they share the same word of "timing" doesn't mean that they have anything to do with either other. Just remember; the distributor moves independently of the cam, so the ignition timing can be set anywhere you want it to be, regardless of where your cam is phased at.

what does ignition timing have to do with cam timing

I've heard some guys say that if the cam is advanced 4 degrees it'll make the ignition timing advance 4 degrees as well. Well yeah maybe if you were able to time your engine first and then go back and move the cam forward or back 4 degrees afterwards, (because the cam drives the distributor), but that's not the way it works. You set the ignition timing long after you've built the engine and installed or degreed the cam, so where the cam is phased at has absolutely ZERO to do with what the outcome will be for the ignition timing. Again, they may both share the same word of "timing", but other than that, they have absolutely nothing to do with each other anymore than a rear main "bearing" has anything to do with a wheel "bearing".

If your engine likes 36 degrees of total timing, then that's where you set the timing at, whether the cam is 2 degrees retarded, 4 degrees advanced, or straight-up, it makes zero difference because neither have anything to do with each other.

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