HEI Weights: How floppy is too floppy?

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MrSony

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Nov 15, 2014
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MrSony

Geezer
Nov 15, 2014
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Des Moines, Iowa
The question is at what RPM do you want timing all in? Did you use the appropriate springs?
Timing, 22* of it, is all in by 2600rpm. I noticed recently that for some reason my car has an extra 10* of timing at idle and is idling higher as a result. tried unplugging vacuum advance (even tho it's on ported), no change. try to change timing back to 12* like I had it, engine runs like *ss. plus timing jumping around.
 

lilbowtie

Comic Book Super Hero
Jan 7, 2006
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You seem to have quite a bit of cam to distributor clearance and also check how much up and down clearance the distributor shaft has to the housing not that that should matter because the the distributor is turning CCW and should be pulled down. You might also try moving the crank back and forth to feel for timing chain slop. Just some checks.
 
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Bonnewagon

Lost in the Labyrinth
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Sep 18, 2009
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My buddy has a Pontiac 400 and his timing advance springs are so bad that the timing light mark won't stand still enough to know what the timing is. Whoever "built" the distributor used the weakest springs available. I advised him top get the strongest springs in the kit- (silver?) - and see what the timing advance is. Then work back if necessary. Compared to stock springs even the strongest in the kit are loose. Then he needs to test- test- test. Bottom line is that they need to be strong enough to keep the timing steady at idle even with a lumpy cam. Also you should tighten up the distributor gear clearance to between .005-.010".
 
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83MonteCarloSS

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Oct 5, 2015
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Timing, 22* of it, is all in by 2600rpm. I noticed recently that for some reason my car has an extra 10* of timing at idle and is idling higher as a result. tried unplugging vacuum advance (even tho it's on ported), no change. try to change timing back to 12* like I had it, engine runs like *ss. plus timing jumping around.
That is why I got the progression ignition distributor. I checked my timing and I couldn't get enough mechanical advance so it was either bump up the initial timing which meant hard starting or set the initial and not have enough at WOT. I had 2 distributors and couldn't get either one where I wanted them.

Either way was a compromise. My plugs would foul out pretty regularly. I was chasing my tail and it had been that way for 20 some years since the motor was rebuilt and the computer controlled setup was eliminated.

I will never go back to the HEI. The new distributor was a drop in swap, you set the initial at 10 degrees, then set up the timing table, rpm limit, to whatever you want on the fly through Bluetooth, and it has ignition lock out. My plugs look beautiful and the motor is running better than it ever has.

My timing was jumping all around on the timing light before I replaced the distributor but found out through the process of elimination that my plug wires were too close together and it was inducing spark across wires. Spacing the wires apart took care of that.
 
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Rt Jam

G-Body Guru
Mar 30, 2020
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The tension means nothing to us in a video. That needs to go in a car or a distributor machine.
Then see the rpm required to change the ignition timing.

Best to plot the timing on a graph. Idle, 1000, 1500 and go up in 500 rpm increments. In a car you should use a dial back light.

The amount of weight also effect advance as does springs. You can also limit the travel to make initial and total closer together.
 
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MrSony

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Nov 15, 2014
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I seem to have found the issue. The vacuum advance tab that holds the rod was catching on the limiter plate and hanging up I guess. bent it up a bit and its back to normal, 12* at idle, 22* mechanical, 8* of vac. advance. timing all in by 2600.
 
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Burd

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Apr 7, 2021
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I was thinking og getting a dust machine, I know a guy who has 2
yiu don’t see many
 
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