Timing for a 72 454?
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Joined: Apr 2007
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RE: Timing for a 72 454?
Sorry if you misunderstood but this is for the 1972 454 Vette I just got. It has a rebuilt 750 cfm Rochester quadrajet and I just converted the stock dizzy to electronic with an Ignitor II setup and a Flame-Thrower II coil. While we are on the subject the + side of the old coil had a 12 guage black wire and a 18 guage red one. What is the black wire? If the red is the 12 volt power then it needs replaced. The instructions say to use 12 guage wire. It seems to be breaking up when running. I'm thinking this might be the problem. I got it to run turning the dizzy till it seemed to be running its best. I just wanted to know the setting to see if this helps. I was thinking probably 6 to 8 degrees? Thanks!
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Joined: Apr 2006
Posts: 4,212
From: KC, MO area
RE: Timing for a 72 454?
Ususally on the stock system, the coil gets +12V when the ignition is in the Start position and then drops to about +8V in the Run position due to a ballast resistor or a section of resistor wire in the harness. This was to limit the current thru the points to make them last longer. So you need to make sure what voltage you coil & distributor is to run at. Don't want to smoke it. [
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As to timing, I agree w/ your idea of using what runs best. I'd start around 10-12 but depends on your CR. Also what your mech. and vacuum are.
]As to timing, I agree w/ your idea of using what runs best. I'd start around 10-12 but depends on your CR. Also what your mech. and vacuum are.
Thread Starter
Joined: Apr 2007
Posts: 21
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RE: Timing for a 72 454?
If that's the case then I'll have to run a new wire from the fuse block. You need a constant 12 volts or the car will not run right. Any idea what the 2 wires on the + side are. The 18 guage is probably the 12 volt feed but what about the black one? The car has a cable driven tac. that runs off the dizzy body. Could it be for the voltage guage?
Thread Starter
Joined: Apr 2007
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RE: Timing for a 72 454?
The numbers cast on the intake manifold in front of the dizzy are J1 71 and on the clock dail behind the carb it's at 2 o'clock with the 0 being 12. Can't read the front of the block anymore as its been painted over. Any place else to look? 77 has a built up engine not the stock one.
Senior Member
Joined: Aug 2006
Posts: 1,152
From: NC
RE: Timing for a 72 454?
Hi again, someone else will help you decode your motor, in the mean time timing for BB in Haynes is listed from 4* to 12*, that's just general information so you'll have to go with trial and error.
4* to 12* is your initial timing,
you want 36* at 3000 rpm
that's 12* initial plus 24* from centrifugal.
Your vacuum advance comes into play at idle and steady cruise, you want no more than 52* total.
Doesyour new distributor have weights and an adjustible vacuum can?
Do you have a dial back timing light?
Also why do you need full 12 volts to the distributor? PG.
4* to 12* is your initial timing,
you want 36* at 3000 rpm
that's 12* initial plus 24* from centrifugal.
Your vacuum advance comes into play at idle and steady cruise, you want no more than 52* total.
Doesyour new distributor have weights and an adjustible vacuum can?
Do you have a dial back timing light?
Also why do you need full 12 volts to the distributor? PG.
Thread Starter
Joined: Apr 2007
Posts: 21
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RE: Timing for a 72 454?
Itsthe stock dizzy modified with electronic ignition. It has the weights under the rotor and a vacuum can.The instructions for the Ignitor II say make sure you have a full 12 volts going to the red ignitor wire. If you don't the car will run rough or not start at all.That's the red wire on the pickup that goes to the + side of the dizzy. The black wire on the pickup is on the negative side.