Mid-rpm knocking
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Senior User
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From: TX
Mid-rpm knocking
I switched over to a Duraspark II in my '72 400. I've had issues with detonation in the past, and now with this setup it starts pinging at about 2200rpm, but not when I have it floored.
Other than installing a more restrictive limiter plate, what can I do about it?
Other than installing a more restrictive limiter plate, what can I do about it?
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Joined: Nov 2007
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From: Denver Metro Area, CO
Under what kind of load? When floored, I'm assuming either you or an automatic
transmission downshifts to a lower gear. I would probably retard the ignition timing
before I started messing around with other stuff.
transmission downshifts to a lower gear. I would probably retard the ignition timing
before I started messing around with other stuff.
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Senior User
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From: TX
I have it at 8* now. Also, the dizzy would be a stock 1977 HEI type, and my motor has the EGR disconnected and all the smog stuff removed, which has been a challenge to get it re-curved right.
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Joined: Nov 2007
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From: Denver Metro Area, CO
Looks to me like you've answered your own question....
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From: TX
I have the stock 2100 in it. Saturday I acquired a 13L limiter with two strong springs and got rid of most of the knocking, but there is still some there.
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Lead Driver
Joined: Mar 2004
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Regular load, no extra weight. When I mean "floored" I mean to say that I'm giving it a good amount of gas, but not to the point that it's downshifted.
I have it at 8* now. Also, the dizzy would be a stock 1977 HEI type, and my motor has the EGR disconnected and all the smog stuff removed, which has been a challenge to get it re-curved right.
I have it at 8* now. Also, the dizzy would be a stock 1977 HEI type, and my motor has the EGR disconnected and all the smog stuff removed, which has been a challenge to get it re-curved right.
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Laughing Gas
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From: southeren Oh
Years ago crane sold a adjustable vacum advance unit. I have one on my truck. You adjust the how much spring pressure by turning a allen bolt inside the unit.
look for Crane Cams part # 99607-1 I hope you can still get them.
If I remember right Crane was the only people with these years ago.
Lead Driver
Joined: Mar 2004
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I drilled and tapped a few small holes in the vacuum advance arm inside my dizzy & made a little stop arm to limit the vacuum advance in it. I saw a guy on here that drilled a bunch of small holes in the arm and just tryed a small roll pin in each hole till he got his to stop the pinging.
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