Re: Distributor advance spring

[jlandry@domain.elided (John A. Landry)]

As the putrid festering facial boil erupted, "Neff, Matthew John - MBA"
<NEFMJ124@domain.elided> yelled:

>Just a small question- is anyone out there familiar with the innards of a
>stock Scout II ('73) Holley distributor?  I took the thing apart to clean it
>up / regrease it, and I found something kind of odd- one of the centrifugal
>advance weight springs is pretty loose on its post (and the other is much
>tighter).  Is this normal?  I didn't want to mess with it too much, so I put
>it back together and reinstalled. Runs pretty much the same now as before.
>Anyhow, I'm  pretty unfamiliar with distributor guts and how they work, so
>I'm a bit lost on this one.  Thanks

Matt,

This is perfectly normal.  The loose spring is what's called your
"secondary" advance spring and the one that's tight is the "primary"
advance spring.  The way it works, is that the primary advance spring
controls the advance curve in the lower rpm ranges and the secondary spring
comes into play in the higher rpm ranges.  Since the secondary spring is
slack at lower distributor rpms, it has no influence on the advance curve.
As the rpms increase and the slack is taken out of the secondary spring, it
acts to flatten out the rising advance curve and hold it to a predetermined
peak.  The two springs act together along with the mass of the advance
weights to give the distributor it's advance curve characteristics.  In
addition to bending the thin metal tabs which the springs are attached to,
the springs and weights can be replaced in various combinations to change
the advance curve characteristics.

That being said, do not be alarmed if you someday see a distributor which
has no slack at rest in either of the springs.  I've seen several rebuilt
IH / Holley distributors like this.  It all depends on the design of the
spring used in the rebuild as to whether they have slack.  Some advance
springs are of a "progressive" design so that they have very little tension
when stretched slightly, but increase sharply in tension as the spring is
stretched.  The end result is the same.  When in doubt, you can always have
the distributor tested to verify it's within spec.

Regards,

John

>P.S.- does anyone by chance have a working  Scout II windshield wiper switch
>that they could bring to the NWBRU?  The washer function is inoperable on
>mine and I'd like to find one that does...

Did you try NAPA?  I think these are readily available new.

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