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7.4 Vortec timing issues
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Post 7.4 Vortec timing issues 
i just got the 454 back in my 97 dually (motor out of 2000 3/4). we went .30 over, stroker crank and RV style cam. went back together great but im having trouble with the timing. the GM tech i had try and dial it in once i got the distributor set says it's 42* out. ive moved teeth both directions but itll only run where it is. runs pretty good in the slot its in but its still saying its out 42*. any ideas? it is a new distributor. i didn't think to count the teeth on the gear. i'm gonna check that asap. could it be anything else?

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Move the plug wires by 1. 360 degrees / 8 = 42. Move them in the right direction and you should find yourself 3 degrees out.

The teeth on the distributor gear should be right. If they weren't then you'd either not get the distributor installed, or if it did somehow install then you'd not get a steady reading because the distributor would not be moving at half the engine's speed and it wouldn't run at all.

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Speeder wrote:
Move the plug wires by 1. 360 degrees / 8 = 42. Move them in the right direction and you should find yourself 3 degrees out.

The teeth on the distributor gear should be right. If they weren't then you'd either not get the distributor installed, or if it did somehow install then you'd not get a steady reading because the distributor would not be moving at half the engine's speed and it wouldn't run at all.


Thanks for the reply. if you could elaborate, what do you mean move the plugs wires by 1?

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He will have a Vortec cap. You will not reach the other side with the wires IIRC. The older Chevy's I would do that to keep it correct.

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Chevy 97 wrote:
He will have a Vortec cap. You will not reach the other side with the wires IIRC. The older Chevy's I would do that to keep it correct.


Crap, that's right. Never mind. It would require lifting the distributor out, moving it a couple of teeth, then setting it back in to move it. This would take some time to get nailed down. Incidentally, it's possible for the engine to run at around 40 degrees advanced. The computer likely is adding 0 degrees of timing because any time it tries to add some it would start picking up knock. I'm surprised there's no code set though. Probably the easiest way to make sure you have the distributor set correctly would be to bring the #1 piston to top dead center, with both intake and exhaust valves closed. Locate the #1 plug on the cap, then mark the distributor base so that there is a visible mark showing where #1 is. Then, drop the distributor into the engine. With the distributor fully seated, the rotor should be pointing right at the mark. Since the gear is curved, you'll want it to be pointing a ways past the line on the distributor. As the distributor settles, it will move towards the mark.

What I meant before Chevy97 reminded me of the Vortec having a crab cap, was remove one wire, then move the rest of the wires by one terminal, then put the first wire back on, which would have rotated the wires around the cap by one.

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I think I might know what you're seeing. That number isn't accurate. I've seen that on one of mine. If you're not getting a code of P1345 then the distributor position is fine. Wouldn't run at all if it was a tooth out either direction because there's just not enough freedom to rotate the distributor behind an L29 intake manifold to compensate.

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ok, ive finally gotten around to tinkering with this thing trying to get it lined out. The autozone distributor thats been in it since it was put back together was showing -42 degrees. we put the stock distributor back in and we can get the computer to bring it to -12. granted it runs much better, but still not the prime -2/+2 that its supposed to be. what can i try next? can i convert to an aftermarket distributor that isnt the flat style?

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Remove the roll pin retaining the gear, rotate the gear 180* re-install the pin.

The gear has uneven # of teeth so it will give a different range of degreeing

+- 13.8* to be exact (IIR, the gear has 13 teeth)

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CrazyHoe wrote:
Remove the roll pin retaining the gear, rotate the gear 180* re-install the pin.

The gear has uneven # of teeth so it will give a different range of degreeing

+- 13.8* to be exact (IIR, the gear has 13 teeth)



That's a great idea! Ill let you know how it works!!!
Thanks!

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