Distributor Advance

[John Vardanian]

The weights in the centrifuge are aided by small coil springs. The springs are unequal length. Does anyone know whether this is so because each weight impacts a different section of the advance curve? I am trying to get my curves to match perfectly and thought I could manipulate the springs and be able to accomplish this. Or maybe not. Anyway, comments are appreciated. Thanks.

john

[Steve Meltzer]

John, I'm sure you're right about the spring tension being used to change the effect of those advance weights. Sure would be nice to have a distributor calibration machine to sort that out quickly and accurately. steve meltzer"never enough time to do it right, always enough time to do it over"

[John Vardanian]

The weight with shorter spring doesn't press against the wall of the centrifuge until the distributor spins faster than say about 1500 RPM, this makes me think that the upper range of the curve is dictated by the shorter spring. Right?

john

[Steve Meltzer]

Sure makes sense to me. I don't know about the Ferrari springs, but on some 'Vette distrbutors I think the difference is color-coded by spring tension. Same, but different. s

[Steve Meltzer]

oops, I meant distributor, sorry about the poor spelling. steve (Archie P. Riechel Spelling Champion, Kemper Military School, '64-'65)

[John Vardanian]

At least you tried, Steve. I did the best I could with stretching and shrinking the coil springs and got the advance curves of the two distributors as close to unison in the mid range as possible. It would be nice to replace the coil springs if we could find the parts. Better yet, it would be nice if we could find the two weights' relationship to the advance curve.

john

[kare]

What would you like to know? It is a pretty normal progressive system where the softer spring controls the advance til 2000 RPM. When the shorter spring makes contact, the other spring makes contact and they reduce the increse of advance curve together. It is impossible to make it perfect, but it didn't matter much as the advance reaches maximum at 7000 anyway and the distributors are in perfect harmony where you need all the power.

[John Vardanian]

That's right Kare, I kind of figured it out over the weekend, except the max advance is hit at a much lower speed, more like 3700 RPM. Thanks.

john

[carello]

I found this in my files for S85A. Is this fitting for all S85A applications? I would guess if another curve was required , it would require another version of an S85
Cheers
Craig
3700 rpm distrib=7400rpm engine

[John Vardanian]

Craig, thanks, I suppose if the x is in engine RPM, then the y must be flywheel degrees, correct? Typically these curves are in distributor speed vs distributor RPM. The S85A runs out of advance around 1900 (distributor) RPM.

john