Pertronix 1181 stock 72 350

[kna4977]

In the process of installing a pertronix 1181 in a stock 72 350. Directions mention with or without ballast resistor. I don’t see a ballast resistor. Believe it has a resistance wire instead. Would I just wire up as if it doesn’t have a ballast? Also has a condenser on the points set, but also another on the coil bracket. Would I keep this or eliminate it. Lastly has a stock 293 coil. Am I ok to keep using that?

[Rich69shortfleet]

I've had a 1181 set on my Chevelle for 25 years and have never had a problem. Car has a resistor wire. The point set goes away entirely (kind of the whole point of the Pertronix set up). Keep the condenser on the coil, helps keep radio buzz from happening. Be sure to shim the distributor shaft per the instructions if the distributor is worn and has a lot if up and down movement on the shaft.

[kna4977]

Originally Posted by Rich69shortfleet

I've had a 1181 set on my Chevelle for 25 years and have never had a problem. Car has a resistor wire. The point set goes away entirely (kind of the whole point of the Pertronix set up). Keep the condenser on the coil, helps keep radio buzz from happening. Be sure to shim the distributor shaft per the instructions if the distributor is worn and has a lot if up and down movement on the shaft.

Minimal up and down movement. Clearance for module to ring is in spec .010-.060. Did test the vacuum advance and it doesn’t hold vacuum or move at all. I’ve ordered a new one, but the truck runs fine so do I really need it working?

[HO455]

The Pertronix will work fine with the factory coil and ballast resistor. You just need to supply it with 12v.

If you refer to fig 3 in the instructions it shows positive 12v power to the unit being hooked to the ignition switch side of the ballast resistor. We have a ballast wire instead of a resistor. Hooking the unit to the ballast wire will only provide it 8-9 volts which isn't enough for the unit to operate properly.

This means you will need to find a different 12v positive supply from the ignition switch. That provides power in the run and start positions from the ignition switch.

Or hook the 12v positive supply to the Pertronix to the ballast wire where it exits the connector on the firewall.

Or remove the ballast wire and replace it with regular wire and replace the factory coil with one that works without any ballast wire or resistor. And hook the unit to the 12v supply at the coil. That is how mine is hooked up on my Burban.

[HO455]

Originally Posted by kna4977

Minimal up and down movement. Clearance for module to ring is in spec .010-.060. Did test the vacuum advance and it doesn’t hold vacuum or move at all. I’ve ordered a new one, but the truck runs fine so do I really need it working?

The vacuum advance not working is going to make your fuel mileage suffer as well as give you a small vacuum leak.

[kna4977]

Originally Posted by HO455

Or hook the 12v positive supply to the Pertronix to the ballast wire where it exits the connector on the firewall.

Would that not be the same as hooking the Pertronix red wire directly to the + side of the coil?

[Stanco]

The black wire on the 1181 connects to the negative (-) terminal on the coil.

Don't connect the red wire to the positive side of the coil as this terminal is powered via a resistor wire and supplies reduced voltage to the coil.

The red wire needs a full switched 12V ignition source. The pink wire on the fuse panel is a great place to power up the 1181.

The reduced voltage is fine for the coil but the 1181 module needs a full 12V.

[HO455]

No. The ballast wire acts as a resistor and causes the voltage to drop down to the 8-9 volt range which is too low for the Pertronix.

To see this check the voltage at the positive terminal of the oil when the engine is running.

The ballast wire on our trucks starts at the firewall terminal and goes to the coil. It is the cloth sheathed wire pointed out in the photo.

[kna4977]

Originally Posted by Stanco

The black wire on the 1181 connects to the negative (-) terminal on the coil.

Don't connect the red wire to the positive side of the coil as this terminal is powered via a resistor wire and supplies reduced voltage to the coil.

The red wire needs a full switched 12V ignition source. The pink wire on the fuse panel is a great place to power up the 1181.

The reduced voltage is fine for the coil but the 1181 module needs a full 12V.

Great thanks pics help! If I switch out to a flame thrower coil, would that change anything as far as the current stock wiring setup or would I wire it up the same way as the stock coil with the factory wiring including the resistor wire? I would like to do this without hacking any of the original wiring.

[Stanco]

The large pink wire that runs to the idle stop solenoid is also a good switched 12V source.

[Stanco]

The 1181 requires between 1.5Ω to 4.5Ω on the primary ignition circuit.

The stock resistor wire on my truck has a value of 2.5Ω plus a 2Ω coil for a total of 4.5Ω.

As long as your aftermarket coil is equal to or less than 2Ω it will work well with the resistor wire.

[Accelo]

The resistance in the wire supplying voltage to the distributor changes with length. I cut the resistance about an inch long at the firewall plug and soldered a wire to it. Everything stays the same that way, including the factory fusing and switching. I couldn't even measure the voltage drop that way.
When I change to an HEI I do the power supply the same way. It has worked out well over the years.
Cheers

[Rust_never_sleeps]

For those of you keeping score at home....

[kna4977]

Originally Posted by Stanco

The black wire on the 1181 connects to the negative (-) terminal on the coil.

Don't connect the red wire to the positive side of the coil as this terminal is powered via a resistor wire and supplies reduced voltage to the coil.

The red wire needs a full switched 12V ignition source. The pink wire on the fuse panel is a great place to power up the 1181.

The reduced voltage is fine for the coil but the 1181 module needs a full 12V.

I have that pink wire but mine doesn't have an extra wire or plug like the one in the picture. There is nothing plugged in under that wire on mine where the more red wire is plugged in underneath the pink wire, in the picture, Could I just attach there?

[Stanco]

Originally Posted by kna4977

There is nothing plugged in under that wire on mine where the more red wire is plugged in underneath the pink wire, in the picture, Could I just attach there?

Yes, that empty terminal will work fine. On my truck that terminal supplies switched ignition power to the idle stop solenoid on the Quadrajet carburetor.

[HO455]

Originally Posted by kna4977

I have that pink wire but mine doesn't have an extra wire or plug like the one in the picture. There is nothing plugged in under that wire on mine where the more red wire is plugged in underneath the pink wire, in the picture, Could I just attach there?

Shooting from the hip I don't remember if that is powered when the ignition switch is in the start position. It's easy to check with a test light before you start wiring.

[Rich69shortfleet]

Originally Posted by Rust_never_sleeps

For those of you keeping score at home....

Bingo. I've had my 1181 connected to a resistor wire for 25 years and have never had a problem.

To the OP: Yes, you need a properly functioning vacuum advance. Two additional comments on vacuum advance: 1. Works best connected to manifold vacuum instead of ported vacuum and 2. Not all vacuum cans are the same, make sure you get the proper one for your particular application. Depends on the vacuum signal your engine makes at idle and full throttle.

[kna4977]

Originally Posted by Stanco

The 1181 requires between 1.5Ω to 4.5Ω on the primary ignition circuit.

The stock resistor wire on my truck has a value of 2.5Ω plus a 2Ω coil for a total of 4.5Ω.

As long as your aftermarket coil is equal to or less than 2Ω it will work well with the resistor wire.

The aftermarket coil would be a flamethrower coil. The factory coil on mine is a Delco 293. Could I use either one and wire up just like factory with resistor wire in tact?

As far as the module itself I plan to wire it either to the vacant post on my fuse panel in the picture or to the idle stop solenoid.