# qustions regarding a HEI distributor



## danthepontiacman (Jul 5, 2008)

ok i was at the tupe;o blue swade cruise in tupelo ms and i got a pro comp distributor for $60 to replace my original points distributor whitch has around 170'000 miles on it. i know points have a resister in the wire going to the distributor and that would need to be bypassed ( none on firewall) my question is what do i need to do? it didint have instructions with it, do i need to bypass the resister wire or run a new wire? what wires hook were? do i just abandon my firewall mounted coil? the distributor i got a a pro comp HEI unit, red cap brass terminals and looks good and yea i know its made in china but i want the better performance of the electronic ignition unit. anybody have any wireing diagrams or anything? any other parts i need to buy?


----------



## dimitri (Feb 13, 2009)

I left my resistor wire alone and ran a new wire to the coil. Make sure it is only hot when the key is in the run position and not acessories.


----------



## danthepontiacman (Jul 5, 2008)

ok, since the hei unit has its own coil ontop i was planing on just leaveing the original wire and coil in place, what wire did you hook into for power? my cars a 66


----------



## jetstang (Nov 5, 2008)

My 66 used 2 wires to run the HEI, 1 from the run position and 1 from the crank position. I ran a relay with 2 switches on it to run the dizzy, 87 and 87a, both turn the relay on. It's a 5 pole switch.


----------



## danthepontiacman (Jul 5, 2008)

what you mean 87 and 87a? that wire numbers or what?


----------



## jetstang (Nov 5, 2008)

No, the relay itself is labelled with a small wiring schematic showing 87 and 87a terminals, and those are both imput switches. I was using headlight relays to run my fuel pump and ignition and they only have 4 connectors, 87 being the switch to turn the relay on. While on my 66 I needed a second input to turn the relay on, thus the 87a terminal. I wish I had a P/N for it, but don't.


----------



## freethinker (Nov 14, 2009)

you dont need the crank wire. all you need is one hot switched wire to the dist.


----------



## jetstang (Nov 5, 2008)

Free, I hear you. on my 70, I removed the cap, hooked it to the HEI and it worked. The problem with the 66 is it uses a run wire from the starter during cranking, so you need a wire that is hot in crank and run position.


----------



## danthepontiacman (Jul 5, 2008)

well if i desided to cut out the original resister wire were would i cut? ive looked and all the wires apear the same size so idk how long the resister part is or were it is, someone should make a kit for this =/


----------



## SLSTEVE (Dec 8, 2020)

danthepontiacman said:


> well if i desided to cut out the original resister wire were would i cut? ive looked and all the wires apear the same size so idk how long the resister part is or were it is, someone should make a kit for this =/


The resistor wire is 33 or 43 inches long, can’t remember which. I am doing this very same procedure as I bought the wrong engine harness for my build. Should have bought the HEI distributor harness but bought the points distributor harness and the HEI auxiliary harness, thinking it would plug in somewhere on the points harness and everything would work, but didn’t happen.

I bought a couple of the twin lock connectors and robbed about a foot of the same gauge wire as the pink HEI auxiliary harness. I plan to remove the resistor wire from the bulkhead block by removing its twin lock connector and replacing it with the section of wire that I robbed from the original harness. To this wire I will splice the pink HEI wire and the brown and yellow wire that is currently spliced to the resistor wire.


----------



## BearGFR (Aug 25, 2008)

danthepontiacman said:


> well if i desided to cut out the original resister wire were would i cut? ive looked and all the wires apear the same size so idk how long the resister part is or were it is, someone should make a kit for this =/


Don't cut it! That's -way- too much unnecessary work, and "what if" some day you decide you want to go back to 100% original? Instead, go to your local big box parts store and purchase a generic headlight relay. 

One of these for instance.

It has 4 terminals. One 'pair' is used to trigger the relay, the other 'pair' acts as the 'switch'. In the link I posted above to the photo, the two terminals marked 85-86 are the trigger pair, the other two marked 30-87 are the switch pair.

Mount it to your firewall near your distributor. Connect the original ignition wire (that went to the coil) to one of the 'trigger' connections, connect the other trigger connection to a good ground. The relay doesn't 'care' if it's being triggered through the resistor wire or not - it works just fine either way.

On the other side (the pair of connectors that are the 'switched' pair), connect one terminal to any convenient full 12v source, the other terminal to your new ignition input. 

Viola - a full 12v supply to your new ignition and you didn't have to find or cut anything on your original harness to get it. Plus it'll be simple to 'go back' if you ever want to.

I've been running the HEI in my '69 exactly like this for going on 10 years now.

Bear

p.s. 
You can also, if you like, add a hidden switch somewhere that you can use to 'turn off' the power to the trigger side of the relay as sort of a poor man's theft deterrent to disable the ignition. Instead of connecting the output side of the trigger directly to ground, connect it through that switch and then to ground.


----------



## SLSTEVE (Dec 8, 2020)

BearGFR said:


> Don't cut it! That's -way- too much unnecessary work, and "what if" some day you decide you want to go back to 100% original? Instead, go to your local big box parts store and purchase a generic headlight relay.
> 
> One of these for instance.
> 
> ...


Wow, Bear, what a revelation! Even though I just received two new dual lock connectors, I think I will give this a shot! Knowing little to nothing about electronics, tell me where to get the twelve volt source from. Specifically. Think I will go out now and reward the harness! Thanks, Bear.


----------



## BearGFR (Aug 25, 2008)

The most obvious spot is directly from the battery (make sure to include an in-line fuse holder if you do). If you'll look at your factory fuse panel, you'll probably find some unused spade connectors there that you could hook onto. Just make sure to pick one that gets switched on and off with the ignition, not all of them do - some will be live all the time. That's how I have mine connected. I ran the wire from the trigger side of the relay "through a convenient hole in the firewall" and connected it to one of those.

Bear


----------



## SLSTEVE (Dec 8, 2020)

BearGFR said:


> The most obvious spot is directly from the battery (make sure to include an in-line fuse holder if you do). If you'll look at your factory fuse panel, you'll probably find some unused spade connectors there that you could hook onto. Just make sure to pick one that gets switched on and off with the ignition, not all of them do - some will be live all the time. That's how I have mine connected. I ran the wire from the trigger side of the relay "through a convenient hole in the firewall" and connected it to one of those.
> 
> Bear


Thanks much Bear!


----------



## Lemans guy (Oct 14, 2014)

I run my ignition with a relay like Bear as well. It is also good if every wire you have is not new. A relay can be triggered by 6 volts and stay closed with 1 1/2 volts. So if you do have any resistance in a wire it won’t hurt things so easily....


----------



## SLSTEVE (Dec 8, 2020)

Lemans guy said:


> I run my ignition with a relay like Bear as well. It is also good if every wire you have is not new. A relay can be triggered by 6 volts and stay closed with 1 1/2 volts. So if you do have any resistance in a wire it won’t hurt things so easily....


I ordered a relay and will pick it up this afternoon. Big relief for me. Thanks for the input.


----------



## Lemans guy (Oct 14, 2014)

These relays rarely if ever fail. Nevertheless I have a spare relay right next to the one I am using,....if I have suspect the relay of failing, I can just plug it into the spare one...and keep going!


----------

