My ZZ3 has the factory performance centrifugal advance curve. But I have been having some timing problems due to the "c" advance already coming into play even at 800 rpms. The factory timing settings should be 10 BTDC at 800 rpm with the vacuum advance disconnected.
Question is:
How can I tell if my timing is correct at 800 if the advance moves it up to 12-13 degrees?
To me, it looks like the centrifugal advance should not be active at idle. Am I wrong in thinking this?

I checked the springs and found one of them broken. I replaced it with a spare but the advance is still there at 800 rpms.
Please help.
Bill


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Long time Chevelle fan and an owner since 1973 :)

My advance starts to kick in around 850 - 900 RPMs. Generally I try to keep my idle below this specified amount so the cent advance won't be in at idle. Also remember when the car is put in gear (assuming automatic), the idle will drop even more, keeping the advance from coming on at a stop.

Determine what advance your distributor is supposed to give at, say, 3000 rpm and then check timing at that rpm with the vac advance disconnected. On my 396, advance is all in at 3000 rpm so I set timing to give 38 deg at 3000.

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Fred Aldrich
Web Site: www.GeoCities.com/~69_chevelle (http://www.GeoCities.com/~69_chevelle)