HEI in Mopar ECU casing

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@TrailBeast am I on the right track with my previous post?

Also, I am running the typical Champion plugs. Should I switch over to Bosch or NGK or just gap the Champions differently?
 
HEI module mounting holes have a metal insert in them, those inserts are the ground point for the module. You will need to solidly mount the module to the mopar brain box to ground it, then ground the box to the inner fender.

Yep you can make the ballast into a jumper, but i would dig out all the potting compound, and remove the old resistor wire completely leaving just the 2 brass terminals on either end then solder in a jumper wire. Thats how i did my ballast resistor, then i filled it back up with 5 minute epoxy.
 
Ok so I can just run a ground wire from that metal insert on the bolt hole of the HEI module and run that to the heatsink portion of the orange box as a ground? How did you attach the HEI module so it wasn't just floating?

Good idea on pulling out the old resistor wire, thank you! What gauge did you run?

Can you verify my points from the HEI module to the orange box are where I need to run the wires?
 
Havent run it yet. Mine is long term project, just built it up and boxed it for now. I figure my results will be similar to everybody else. I didnt mod a mopar ECU. I didnt want a big honkin box on my fenderwell. I mounted the HEI module directly to my mopar V8 dizzy, and custom made the mopar to GM plug. Bracket can be had from www.designed2drive.com for about $25.

The module needs to be solidly bolted in. One side of it requires heatsink grease, and a heatsink on it or it will burn up. My heatsink is the aluminum adaptor mount plate to attach it to the distributor. And the distributor body is ground.

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Oh gotcha. Yeah I looked at your route as well. Pretty slick either way. If I didn't already have a box and the holes drilled in the fender I'd be going your route I think. That looks good.
 
Notice the white oozing out around the edge of the module. This is the heatsink compound. It helps to transfer the heat away from the module. You can bolt the module to a piece of aluminum w fins cut into it, or in my case its a 1/4" thick aluminum plate. Aluminum will draw the heat away better than steel.

Make a 1/4" thick square aluminum plate for inside inside the box that attaches to the now "fake diode" thats on the outside, drill, and tap the aluminum.block, and mount the HEI module inside the box on the aluminum plate with heatsink grease. Thats solves your heatsink, mounting, grounding issues in one shot.
 
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jrc4y4 said:
@TrailBeast am I on the right track with my previous post?

Also, I am running the typical Champion plugs. Should I switch over to Bosch or NGK or just gap the Champions differently?
Click to expand...

It all sounds pretty reasonable as to what Matt has been telling you, but I would add a FYI.
Those little metal inserts in the HEI module are floating and sometimes don't conduct the ground unless they are squeezed down enough to make a good contact with the backing aluminum.
Bolting the module down to a backing plate/heatsink should be sufficient for that.
Here's a wiring comparison for you.

Your plugs should be sufficient but need to have the gap opened up to around .045

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jrc4y4 said:
Ok so I can just run a ground wire from that metal insert on the bolt hole of the HEI module and run that to the heatsink portion of the orange box as a ground? How did you attach the HEI module so it wasn't just floatinig

Good idea on pulling out the old resistor wire, thank you! What gauge did you run?

Can you verify my points from the HEI module to the orange box are where I need to run the wires?
Click to expand...

Wire hidden in the resistor, can be same gauge as the wires going to the resistor, or thicker.
 
When I look at that I think about the LA location and engine heat that rises up at both module and heat sink. Cooking at hot engine off? I hope it works. Time will tell.
 
Awesome guys thanks for the input. This is all just a fun hot rod trial for me. Trailbeast, did you end up sticking with this HEI or did you end up going the route of doing the GM style HEI where everything is in the dizzy? If I recall you sell something like that. Any discernible difference in it all? I unfortunately just bought a new chrome box and a Rev N Nator coil and am kind of wishing I had gone the HEI route instead. I am very new to stuff like this so correct me if I'm wrong, but I didn't think you can ground to aluminum. Am I wrong in this or am I just thinking about it not being magnetic?

RedFish are you talking about the module under the dizzy like what Matt did? I think guys have had good results from it.
 
I work in aviation, almost a whole aircraft is made from aluminum. Fuselage, wings, tail, etc. Electrical system is same concept positive thru the wiring, negative ground return to the batteries thru the airframe. Metal is metal as far as electrical grounding is concerned as long as its clean to be able to conduct properly. HEI stock distributors are aluminum, and modules are bolted directly to them, wont be any different. You must be thinking about magnetism. You can always sell the chrome box and coil if you dont use them. Or return them if the seller allows returns. Theres guys on here that blaspheme over GM HEI conversions only because they have tunnel vision to anything but mopar. Maybe you can sell those parts to them.
 
Ha good point! The chrome box was bought at Summit a couple months ago and has been used. Not sure Rev N Nator would return a functioning piece. But yeah I could find those guys. I'm borderline one of those guys, hence the desire to do HEI hidden LOL
 
So does this mean your an in the closet HEI guy lol. Come out man its ok. I use GM parts, denso parts, hell i even have a hyundai tiburon part going on my car lol
 
LOL yep, still in the closet about it. Don't know if I can come out about it yet haha
 
jrc4y4 said:
Awesome guys thanks for the input. This is all just a fun hot rod trial for me. Trailbeast, did you end up sticking with this HEI or did you end up going the route of doing the GM style HEI where everything is in the dizzy? If I recall you sell something like that. Any discernible difference in it all? I unfortunately just bought a new chrome box and a Rev N Nator coil and am kind of wishing I had gone the HEI route instead. I am very new to stuff like this so correct me if I'm wrong, but I didn't think you can ground to aluminum. Am I wrong in this or am I just thinking about it not being magnetic?

RedFish are you talking about the module under the dizzy like what Matt did? I think guys have had good results from it.
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I still run exactly the same kit I used to sell.
The 8 pin module on a heatsink and the matching Ecore coil, and all mounted over on the fender side of the brake booster.
It works great, so the only reason I might change it would be for a rev limiter.
I have one but it's a separate box and I really don't want to go that route, but have it built into the ignition module.

Also, the people that worry about heat on the modules are forgetting that they run inside a hot distributor normally.:D
Sorry it took so long to answer, as I am spending every minute I can getting body and paint done before winter.
 
I may be wrong, wouldn't be the first time. Heat rises, and it migrates or wicks to cooler. How can that heat sink be any cooler?
I don't think inside a distributer gets as hot as outside underneath, but yeah... Once upon a time Fords 3.0 V6 was melting down pickups because that cap didn't have sufficient vent on the top. It was at the front of that engine but buried into a hot spot.
Then what ign' module doesn't have a history of heat related failures no matter where it was located?
I guess my main issue is the labor involved in R&R a failed module. Not IF but WHEN that happens. Good luck to all.
 
RedFish said:
I may be wrong, wouldn't be the first time. Heat rises, and it migrates or wicks to cooler. How can that heat sink be any cooler?
I don't think inside a distributer gets as hot as outside underneath, but yeah... Once upon a time Fords 3.0 V6 was melting down pickups because that cap didn't have sufficient vent on the top. It was at the front of that engine but buried into a hot spot.
Then what ign' module doesn't have a history of heat related failures no matter where it was located?
I guess my main issue is the labor involved in R&R a failed module. Not IF but WHEN that happens. Good luck to all.
Click to expand...

I may be wrong as well, but for the sake of the conversation I would mention that I have never had a GM module fail.
(on Fords with the box on the fender I have)
Been carrying a spare around in the trunk for almost 6 years now.:D

Even though, I still mounted mine wayyyy over there.:D
 
I'll repeat AGAIN "what I got away with". Just to see if I could get away with it, and one hole was already there, I mounted my GM 4 pin on the firewall "flat spot" up below the wiper and to the left of the dist. NO THERMAL GREASE, just mounted with two screws and an added ground pigtail I drove it two summers, both of which got up to 100F

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NOTE that I do not necessarily recommend this. But it DID work!!
 
Prolonged idling (read: stationairy heat) is what kills most modules.
At idle there's plenty of dwell and a lot of power is going through the module, which heats up fast this way. Especially if there isn't any/much engine bay air movement.

I had a module fail years ago in a '86 Opel after getting stuck mostly stationairy traffic jam. The moment the traffic jam slowly dissolved the module crapped out. Overheated.

Had similar happen last year when I ran 4-pin module in my Dart.
Ended up in a big very slow moving traffic jam on the highway lasting for 20orso minutes. Finally got to my off-ramp and half a mile later the module craps out.

I'm currently running a 7-pin module with digital ignition, where I can control the coil's dwell-time better, so less energy goes through the module at idle, thus not heating it up that much.
 
BigBlockMopar said:
Prolonged idling (read: stationairy heat) is what kills most modules.
At idle there's plenty of dwell and a lot of power is going through the module, which heats up fast this way. Especially if there isn't any/much engine bay air movement.

I had a module fail years ago in a '86 Opel after getting stuck mostly stationairy traffic jam. The moment the traffic jam slowly dissolved the module crapped out. Overheated.

Had similar happen last year when I ran 4-pin module in my Dart.
Ended up in a big very slow moving traffic jam on the highway lasting for 20orso minutes. Finally got to my off-ramp and half a mile later the module craps out.

I'm currently running a 7-pin module with digital ignition, where I can control the coil's dwell-time better, so less energy goes through the module at idle, thus not heating it up that much.
Click to expand...
Was it mounted to a good heatsink? My 94 chevy pickup one lasted 160,000 miles before crapping out. Stock location in distributor. Stock 4 pin hei ones are bolted right down inside the aluminum distributor body. Maybe if not on a good finned heatsink, you can hide it inside the car to keep it away from the engine heat.
 
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