Cris---There is potential to damage the pistons when running so much
ignition advance, under some conditions. You have skirted the main one,
detonation, by using 94 octane fuel. This is overkill, when using a head
with a 7.5:1 compression. Most late engines run without pinging, (early
warning detonation) on 87 octane
fuel, and 'normal' ignition advance.
There is a way to have BOTH a lot of advance at idle, AND keep it from
going another 20 deg., as designed, as engine speeds increase the
advance. That is to put a short (1/4" long) piece of nylon-type tubing
over the post that limits the total advance. The thickness of the
tubing will determine at what degree advance stops. If this is unclear
to anyone who has a desire to limit total advance, while wanting more at
idle speeds, take off the 'points' plate and see how the weight
mechanism is designed. You'll see what I am referring to. To test the
theory at one time I was running with 20 deg. at idle, and 30 deg. with
the timing all in. Ran fine, but in my circumstances wasn't necessary,
as my engine happens to idle well anywhere reasonable.
Jonathan, if you're tuned in, I'd like to try this on your '74 to see if
it improves idle. (You know how that bugged me!)
Dick Taylor
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