Thread: 327 timing

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My impala falls on its face at the proper timing under a load only runs at 12-14 degrees advanced, can anyone help me understand??

I don't usually answer first time posters, but since you're from my home state, I'll step up.

While your problem could be any of a hundred things, I'll outline one of the possible problems. What you're seeing with your timing light as 12-14 degrees advanced may not actually be valid because of a slipped damper ring. Harmonic dampers are manufactured with an inner hub and outer ring, separated by a ring of rubber. Under the influence of time, oil and millions of duty cycles, the outer ring can slip in relation to the inner hub and give you a false reading. You can verify top dead center of the motor with this procedure...

Buy or borrow a piston stop. The cheapest I've found is the $7.88 unit, part # PRO-66792 at www.summitracing.com .

Remove all the spark plugs to make the motor easier to turn over by hand. Screw the spark plug adapter into #1 cylinder. Turn the motor over in the direction of rotation (clockwise as you face the front of the motor) until you have the notch on the damper at about 12 noon. Screw the inner rod down into the adapter until it bottoms against the top of the piston. Make a mark on the damper where the timing tab is pointing. Turn the crank counter-clockwise until the piston comes up against the inner rod again. Make another mark on the damper where the timing tab is pointing. Halfway between these marks on the damper is TDC. Use your 6" dial caliper to locate it exactly, then mark the damper with a centerpunch and put a dab of orange paint in the centerpunched cavity.

If the damper is 6.75" diameter, each crank degree will be 0.058902", so for instance if you wanted to mark the damper for 6 degrees and 12 degrees timing advance, you'd make punch marks at 0.353" and 0.707" TO THE RIGHT of your TDC mark.

If the damper is an 8" diameter unit, each crank degree will be 0.069811", so your 6 and 12 degree marks would be at 0.419" and 0.838" TO THE RIGHT of your TDC mark.

Use a dot of white paint in each of the advance punch marks and you're good to go.

Well, there you have the reason I usually don't answer first-timers, not so much as a damned thank you. I'm done.

Originally posted by techinspector1
Well, there you have the reason I usually don't answer first-timers, not so much as a damned thank you. I'm done.

he's still trying to figure out what you said.