Distributor question

[BillC]

Yesterday, I was checking my timing, and noticed something odd: The timing would vary a little bit with RPM, even though the timing wire was already disconnected (I do know how to set the timing. ).

I set the timing at zero, with the engine running at 1000 RPM. When I let it drop back to idle (approx 750 RPM), the timing advanced about 1.5 degrees. When I revved it up to about 2000 RPM, the timing retarded about 1 degree.

Anyway, the question is: is this normal? I thought the timing wasn't supposed to change at all with the wire disconnected. Is my distributor worn out (even though I just installed a new pickup coil and ignition module, the shaft is straight and the bushings are tight)? Or, am I just seeing the effects of torsional load on the camshaft?

TIA

 

[ed hess]

i see a bit of this, was looking at it today to verify what i set timing at the other day after installing the msd8367. I think it s timing chain play if i varies a tiny bit as you slowly raise rpms, but a spike in timing as you rapidly change rpms i think would be the timing light isnt going to operate properly with rapid changes in rpm. I can tell you i saw a lot more with the old distributor than i do the new. This would probably be a weaker magnet in the old, or the gear, or a bushing.
hope this helps, athough im still not sure either.

ed

 

[4C FED]

Check the rotor for rotational play.

I tossed the rotor that came with my MSD dist. because I could rotate it to much when it was fully seated.

I know it sucks that a brand new piece has to be repaired. I had a new Conrad sitting around so it wasn't really a problem.

 

[BillC]

The rotor is okay, it is tight on the shaft and doesn't have any rotational play. The cap and rotor also only have about 3k miles on them, and my truck doesn't eat caps & rotors like some other trucks.