More timing questions - spark plug wire routing

[Mountain Man]

I am in the process of throwing on an Edelbrock Performer EPS manifold, and naturally I have to remove my HEI distributor.

I pulled the cap to the disy, and made a mark on firewall where the rotor was pointing, so I install it back in the same fashion.

I noticed in the book (Edelbrock manual), that they show a top view of the distributor, and have the disy cap spark plug wires labeled 1, 2, 3 , etc. with locations.

Then I noticed that the P/O had #1, 2, 3 , spark plug wires going to a completely different location on the distributor cap, than edelbrock had shown.

I phoned there tech line and the guy said that "it did not matter where the spark plug wires attach at the distributor cap end, you can have them where ever you want". Is this comment correct?

[72 chevy]

YEP! Doesnt matter....as long as the firing order is right. use what looks good and works for you.

[Rakort]

Well, sort of, maybe, no, yes, etc


In thoery you could desiginate any dist cap terminal as number "one" as long as the rotor is pointing to that terminal when the #1 piston is at TDC. The next dist cap terminal in line (in the order of the dist rotation) is desiginated by the next number in the firing order. I believe the firing order for a SBC is 18436572 (don't flame me if I'm worng I remembering back some 10+ years). So in this case the dist cap terminal next to #1 better be going to the #8 spark plug then the next terminal to the #4 plug, etc.

Does this help? I could type all night and try to explan it more, but it will make my wrists hurt.

Good luck.

[72 chevy]

Just plop that dizzy back in with the rotor pointing the same, and youll be fine. Rakort hit the nail on the head there. Alot of confusion seems to come from the fact that GM shows what appears to be the #8 as being the #1 with HEI..but like we said, as long as the firing order is correct, yer good to go.

[Mountain Man]

What do you mean by the firing order being correct, please explain, I am a novice.

[Rakort]

Firing order being correct basically means that you installed you plug wires correctly.

Here I drew you a picture. I needed to draw this out anyhow for my full wiring schematic I created on AutoCAD.

Remember I said the firing order was 18436572...

Notice how the wires on the dist cap are connected. Starting with number 1 and working clockwise around the dist cap they are connected to each of the cylinders in the 18436572 firing order. Each cylinder is numbered per the drawing also.

[Mountain Man]

So using RAPORT's schematic, I can wire my #1 spark plug wire in any position on the dist. cap, as long as I follow the order after the place where I put #1, by the remaining firing order ,right?

Just want to verify this because the P/O has #1 starting on the side.

[Rakort]

OK, were going to get this yet!

So according to RAP or was it Rak?

Go back to my original comments:

"In thoery you could desiginate any dist cap terminal as number "one" as long as the rotor is pointing to that terminal when the #1 piston is at TDC."

Ohh by the way the #1 piston must also be on the compression stroke for the above to be accurate.

Now since you don't know where your #1 piston is, I suggest you put the new dist back in with the rotor pointing in the same direction as the old one and arrange the wires in a similar fashion to the old one otherwise you might be getting into a bit more than you want to. Where ever number one was on the old dist match it and rest should follow the firing order as you go clockwise.

[Mountain Man]

Took me a while, but I finally get it. Thanks very much.

I guess I got thrown by the fact that he has #1 at about the 8 o'clock position. I always thought number 1 started at about 6'oclock like in your drawing.

I guess it is not unusual for engines to have different #1 locations at the distributor cap. I went out and checked and he does have the wires following the firing order after #1 , so I will drop the disributor back in line with the marks I made when pulled out, and keep his plug wire pattern.

Then I need to figure out the easiest way to time the engine.

[rusty ol' 69']

What Rakort is trying to tell you is this:
Your motor probably didn't stop at TDC (top dead center). Most motors won't rest at tdc unless you physically put it there. Therefore, your wiring is probably fine it just didn't stop at the no. 1 cylinder in order to make things easy for you. I think that's were your getting confused. I could be way off on this, but if you do exactly what Rakort said you should stay out of trouble. PUT EVERTHING BACK THE WAY IT WAS WHEN YOU TOOK IT OFF. Unless of course it wasn't running right before you removed it.

Good luck