Quote:
Originally Posted by bignate
AC Delco R43S plugs gapped at .050"
Initial timing is set at 18 degrees
Mechanical advance has the black 18 degree bushing installed and has one light silver and one light blue spring
Vacuum advance is hooked up to ported vacuum, and set to the maximum of 10 degrees
So it should have 36 degrees total all in by 2100ish RPM.
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Quote:
Originally Posted by Will
that's a really fast curve. If it works, it works though. I'd be more focused on your total timing, you may not need that much. If you can get it on a chassis dyno or out to a test & tune day at the track I'd try backing it off two degrees at a time and see what happens. For pump gas you might want to slow it down a bit too. Try pushing the total all in point back to 3000-3200 RPM.
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Quote:
Originally Posted by AG
You need to check what the actual advance versus rpm is rather than go by the theoretical, only takes 5 minutes to check.
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Quote:
Originally Posted by amcmike
I'd regap the plugs to 0.045".
As far as your timing goes, you can still lose power without hearing knock. Starting the ignition too early could be causing negative work as the piston is coming up. By 3000rpm, the timing is probably right where it wants to be and suddenly it picks up. With that short a curve (again assuming you've confirmed the marks are showing correct), I'd slow it way down. Put it the stiff springs and try to get it to not come all in before 3000rpm.
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These guys saved me a lot of typing.
Centrifugal curve too fast. May or may not have the optimal "total" advance. Spark plugs gapped too wide.
I might play around some with the vacuum advance, but not until the rest is sorted out.