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Another vacuum advance question

1409 Views 4 Replies 5 Participants Last post by  FAIRMONT MIKE, 
O
If I run the adjustment screw on the vacuum advance on my stock duraspark dizzy all the way in and all the way out, I'm only seeing about 3-4 degrees, tops, change in the timing. Is this all of the adjustment there is.

The engine runs great. I'm just trying to remove a tiny bit of detonation on light to medium throttle acceleration. My static is at 7 deg.

This isn't an issue except during the peak heat here in Phoenix.

All I probably need is a couple more degrees.

Anyway, is that really all of the adjustment available?

Thanks,

Tom
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jrocco
Ozonkiller said:
If I run the adjustment screw on the vacuum advance on my stock duraspark dizzy all the way in and all the way out, I'm only seeing about 3-4 degrees, tops, change in the timing. Is this all of the adjustment there is.

The engine runs great. I'm just trying to remove a tiny bit of detonation on light to medium throttle acceleration. My static is at 7 deg.

This isn't an issue except during the peak heat here in Phoenix.

All I probably need is a couple more degrees.

Anyway, is that really all of the adjustment available?

Thanks,

Tom
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There should be a lot more adjustment than that. Idealy you would want 10 degrees from the vacuum advance. Maybe it's bad.
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fordman59
There are a lot of cans with different rates and amounts of advance. Depends on the original application. You may want to get another.
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crittersf1
In my experience, that's all you should get out of that adjustment, it's just there for fine tuning.
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F
More of a spring tension adjustment more than total degrees adjustment.
You will notice more tension on the spring in one direction than the other.
On mine when it was on max tension end of the scale, it limited total advance by the fact that my engine would not pull that high of a vacuum to advance it fully, if you can get a vacuum pump you will see what I mean when the engine is running. :)
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