dual points on a SBC

[hudson_hawk]

ok, long story but i have a dual point accel that i picked up at the swap. my questions are thus.

1)on a regular dist. #1 is past the door but this has no door so where/how to locate number one?

2)it only has 1 wire coming off it, shouldnt it have 2?

3)can you run only 1 set of the points?

4)i currently have vacuum advance but there is no provison for it on this dist, does that mean i dont run it or need it on a dual point?

[Fat Hack]

1. Number one cylinder can be put anywhere. It's relative to how the distributor is positioned in the engine.

2. One wire...it goes to the distributor (-) side of your coil.

3. You can swap in a single point plate to only run one set of points...I think, but WHY? Run 'em both!

4. You can run without vacuum advance. Plug the port that your old hose was hooked to. You'll find that economy and part throttle operation suffer slightly without vacuum advance, but I've run full mechanical Accel distributors on the street before and they did okay. It's meant to be a low cost racing distributor for the masses...not neccessarily the best distributor for a street driven vehicle.

[John Copeland]

There is no specific position for the number one wire, make # one, whereever it works best for you, and then insert the remainder of the wires in the proper firing order rotation. You will have to set the dwell by putting a little piece of cardboard in the one set of points, while setting the other, and then reverse the process. Mechanical advance will work just as well as vacuum if set up right, should be able to verify that the advance is coming in, buy checking to total degrees of timing at RPM.
Dual points are kind of a pain in the ass for what their worth.

Shoe

[hudson_hawk]

is there a petronix set up for this. can you add a vacuum advance.

is this worth the trouble or should i hold out for a vacuum dual mallory? its the size of the dizzy i am after more so than performance, my current one hits the back of my carb and i cant get dead on timing which IS a problem

[John Copeland]

Hudson Hawk,
If the vacuum advance is hitting the carb, pull all the wires out, rotate the distributor to where the clearance problems go away, and then reinsert the wires in their firing order sequence. I went to a Mallory Unilite mechanical unit, because I gave up some space in the front when I changed to dual quads and I also needed some additional firewall clearance. The Mallory is smaller in diameter then a stock chevy and certainly smaller then a elecrtonic chevy unit.

Shoe

[hudson_hawk]

[ QUOTE ]
There is no specific position for the number one wire, make # one, whereever it works best for you, and then insert the remainder of the wires in the proper firing order rotation. You will have to set the dwell by putting a little piece of cardboard in the one set of points, while setting the other, and then reverse the process. Mechanical advance will work just as well as vacuum if set up right, should be able to verify that the advance is coming in, buy checking to total degrees of timing at RPM.
Dual points are kind of a pain in the ass for what their worth.

Shoe


[/ QUOTE ]

just to clarify, from top dead center? or does it matter, pick place on diz and start w/ 1 thru firing order.

say points setting on both sets? anyone know of the top what that is for SBC?

[John Copeland]

Hawk,
Rotate the harmonic ballancer up to top dead center where you are sure the rotor points to what is now #1. Pull the distributor out and position it to where ever you have the clearance necessary to avoid any obstructions. You can now stick the dist back in where you want it to be and where ever the rotor points has to be #1. Place the ignition wires back in place using the firing order rotation. My mind is failing me so I can't tell you what the point setting should be but if I remember correctly, the dwell should be half of what the single point distributor used to be.

Shoe

[Gr8ballsofir]

Make sure the #1 cylinder's @ TDC on the compression stroke or you'll be 180 deg. off!! Pull the #1 sparkplug out, put your finger in the hole and turn the crank. When you feel pressure on you finger, you're on the compression stroke.