a Frenchman who needs advice for GM HEI MODULE!!!!

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VINIDAY

VINIDAY

duster 1973 slant six 225 ci
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May 13, 2015
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Hello

I'm changing the harnesses of my Duster from 73 (slant six)
I bought this harness
14 Circuit Plymouth Restoration Wiring Harness

I would like to reduce to the maximum the wires in the engine compartment
and I would like to go through a GM HEI MODULE to remove the ECU box and the ballast resistor.

With you advice to give me for this operation?
is it achievable with this type of harness ??

thank you for your answers and for guiding me in this operation.
 
Last edited:
All you need to do is use the wire/wires (ign1 and ign2) that would normally go to the ballast resistor and go direct to your coil and module.
Normally these two wires can be connected together and run one wire from them to your coil and/or module.

Below is the four pin old style module diagram and the 8 pin module diagram in case you don't have them.
A tach would connect to the coil ground on either system.

4Pin.jpg


8 pin wiring.jpg
 
thank you TrailBeast
I put a new harness, I would not have the wires going to the ballast
 
What "Trailbeast" said, tie the blue/brown circuits together & I would suggest a full 12V E coil. I bought a recommended one from Rockauto for dirt cheap & it has been flawless. be sure to use some heat sink paste between the HEI Module & 3/8" plate of aluminum to mount it on. Powerselect/WPS #CFD 478. I used an OE '75 chebby used HEI module from a yard.
 
The key to making the HEI modules last is heat management. You need to attach them to a good heat sink. Since you are in Europe, look for a Marelli Plex 201 equipped early 80's Fiat, lancia or Alfa Romeo. They have a really well designed heat sink and coil mount combination unit that uses a GM style module. Too bad they're hard to find in the US.

Coil1_1.jpg
 
Actually, Chief, when I installed my 4 pin, "as an experiment" I simply bolted it to the firewall in a flat area......no thermal grease, either!!! I do NOT recommend this method, I mostly did it to see how much "I could get away with."
 
I put a GM 8-pin module on an old PC CPU heat sink cut to size, but a simple flat aluminum plate "should work" (as in TrailBeast' kit) since that is how GM installed them in their small-cap distributor.

A bit late, since you bought a kit, but read my post for ideas on simplifying and upgrading underhood wiring: www.forabodiesonly.com/mopar/threads/modernized-engine-wiring.176755/
 
C130 Chief said:
The key to making the HEI modules last is heat management. You need to attach them to a good heat sink. Since you are in Europe, look for a Marelli Plex 201 equipped early 80's Fiat, lancia or Alfa Romeo. They have a really well designed heat sink and coil mount combination unit that uses a GM style module. Too bad they're hard to find in the US.

View attachment 1715091491
Click to expand...

I found one for sale
I have more pictures soon
1505672023-6bc9364e0e07c790887b30fd1c2b078f4d0956b7-1.jpg
 
Last edited:
TrailBeast said:
All you need to do is use the wire/wires (ign1 and ign2) that would normally go to the ballast resistor and go direct to your coil and module.
Normally these two wires can be connected together and run one wire from them to your coil and/or module.

Below is the four pin old style module diagram and the 8 pin module diagram in case you don't have them.
A tach would connect to the coil ground on either system.

View attachment 1715090680

View attachment 1715090681
Click to expand...
So stupid question. How do I determine positive and negative on the distributor side? I'm using the 8 pin module.
 
If you mean the positive and negative of the 2 pickup wires, what I did was to shine a clamp-on timing lamp at the distributor reluctor and verify the teeth aligned with the pickup when the lamp flashed. Easiest to spin the distributor rotor off-engine by hand. Since the cap is off for this test, connect the HV lead off the coil tower to gnd (or to a spark tester). I think I wrote down the GM wire colors and which pin of the dbl-bullet connector they go to for correct polarity. If wrong polarity, you will still get sparks, but much more erratic since triggered off an inexact point between the reluctor teeth.
 
Screenshot_20221015-101449_Gallery.jpg


Screenshot_20220429-152539_Firefox.jpg


GM HEI & Heat Sink Adapter
Mopar Distributor

'95 Ford F150 Pickup, E-coil

Straight 12 volts from a switched source however you see fit.

Simple, Simple

Screenshot_20210901-024532_Gallery.jpg
 
RustyRatRod said:
I'm at a loss as to how this helps with what I am doing or what I asked.
Click to expand...

Actually Rob, the simplest way to determine the polarity of the distributor wires is to hook them up and try it.
If they are wrong the rotor phasing will be so far off the motor will run like crap, or not at all.
 
TrailBeast said:
Actually Rob, the simplest way to determine the polarity of the distributor wires is to hook them up and try it.
If they are wrong the rotor phasing will be so far off the motor will run like crap, or not at all.
Click to expand...
One more stupid question. Is there a bracket made that will mount the E coil like you sent me? I can make something, but I just hate it. LOL
 
RRR, If using the GM e-core coil like me, the ones I got at the junkyard have a bracket which varies a bit depending on engine. GM mounted it on the intake manifold. Below is how I mounted on the right inner fender of my 1964 Valiant slant-six. Can't quite make out the coil's bracket, but I recall a simple L shape. There are 2 holes thru the bottom of the coil laminations so you could easily roll-your-own L-bracket. The closest you can mount to the distributor, the easier, and near the HEI module if using the GM cable between them like me. Note that I still have wire nuts from verifying polarity of the 2 pickup wires from the Mopar e-distributor (my custom wires don't tell you polarity). The heat sink under the HEI module is probably overkill since GM just mounted to an aluminum plate inside the distributor. I cut it from an old PC CPU heat fins.

Note that I also mounted the Vreg near the distributor which seems simpler than way over on the firewall as Mopar did and I already had IGN power there for the HEI. For those wondering, I added a vacuum-operated valve (vacuum shuts, spring return) to block heater flow when the AC is on. A little electric valve beside it passes intake vacuum from an "ON" signal wired from inside the knee-knocker climate box. Not really needed since the regular cabin blower is off when using AC, but helps manage the heater hoses. I use silicone hose (blue) whenever I can. Also plumbed in a heater core protector valve.

HEI.jpg



My 1965 Newport 383 when I was testing polarity with a timing light, as I explained (spun shaft by hand). Twist the pickup wires to avoid positive feedback by picking up the sparking. The yellow wire is grounded so the sparks jump to it. Note the reluctor teeth align with the pickup when the lamp flashes. I inadvertently had the HEI pickup connector on wrong (fixed), but the photo doesn't show the dbl-bullet connector polarity anyway. I mounted the HEI atop the York compressor since convenient. Also can't see the GM bracket, which was your question, but I recall I cut it so just 2 flat metal plates which are clamped on each side of the York bracket.

note connector is upside down fixed it.jpg


pickup w timing light flash, pickup org wire to HEI white, blk to HEI grn.jpg
 
Last edited:
RRR,
Not sure about the 8 pin module, but the 4 pin is marked G & W. These are the pick up terminals.
White is pos.
Green is neg.
On a Mopar dist, the black wire is neg.
 
Bewy said:
RRR,
Not sure about the 8 pin module, but the 4 pin is marked G & W. These are the pick up terminals.
White is pos.
Green is neg.
On a Mopar dist, the black wire is neg.
Click to expand...
Thanks! That helps.
 
RustyRatRod said:
One more stupid question. Is there a bracket made that will mount the E coil like you sent me? I can make something, but I just hate it. LOL
Click to expand...

There are 3 factory brackets, one is a single short L shape, one is 2 taller L shapes and the other is 2 short L shapes.

A single aluminum L from one inch angle works really well.

My coil is mounted with the taller L type, which I don’t really care for but it works out with where it’s mounted.

IMG_4995.png
 
I am working on a bracket that mounts under the slant distributor. Machine shop should have it done next week. Tell you what I like the flame thrower III .3 ohm coils with them you can mount it in the stock bracket.
 
RRR, Here are some photos of my setup that replaced the MSD ignition. I realize that my setup is fabricated, it is simple and easy to access though.

IMG_0618.jpeg


IMG_0617.jpeg


IMG_0616.jpeg
 
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