HEI in Mopar ECU casing

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I want to say that I used 6-32's to mount the module.

Not a fan of modifying 'wear' parts like the module. Parts like that need to be easy to replace in the field.

I would use flat head screws to bond the two pieces together. Call it 4-8 of them. Clearance drill & countersink one piece and drill and tap the other. On assembly coat one mating face with the thermal compound and then screw them together. Then drill & tap for the module's screws.
 
not happy with how this is turning out. Its going to be hard getting the aluminum plate that the HEI module bolts on to mounted up on the firewall EXACTLY where it needs to be, good and squared up between the factory holes that the mopar box bolts to. If i dont get it right, the factory mopar box wont go right over it. The aluminum plate is just the right size that the mopar ECU box fits around it. Trailbeast, how do you build yours? May just pay you for one, any pics? I like the aluminum plate that was cut out perfect and the mopar ECU sat right on top of someone had pictured..
 
another problem i am going to have, the 4 lugs that i need to solder the wires too, there is barely any metal exposed to solder to, The plastic things that hold them in place come all the way to the top of them, and the plastic is hard as concrete..I just dont think there is enough metal exposed to get a good solder joint to the wires..


The pics earlier in this post where someone did this had about half the metal lugs exposed so there was a lot to solder to and even shrinkwrap!
http://www.forabodiesonly.com/mopar/showthread.php?t=252705
 
mopower440 said:
not happy with how this is turning out. Its going to be hard getting the aluminum plate that the HEI module bolts on to mounted up on the firewall EXACTLY where it needs to be, good and squared up between the factory holes that the mopar box bolts to. If i dont get it right, the factory mopar box wont go right over it. The aluminum plate is just the right size that the mopar ECU box fits around it. Trailbeast, how do you build yours? May just pay you for one, any pics? I like the aluminum plate that was cut out perfect and the mopar ECU sat right on top of someone had pictured..
Click to expand...

I have only ever used the four pin modules in the Mopar box, so I would have to do some creative designing on the inside of the box.
(maybe like JB weld the heatsink metal to the sides of the Mopar box suspended off the surface and put the module upside down on that)
That way it wouldn't interfere with the transistor screws.
 
I would suggest looking into using longer transistor screws to hold the aluminum piece in place if you're going to "invert" the module's mounting. I would also use more of the thermal compound between the aluminum and the case after Dremeling out the plastic so that the aluminum can contact the metal case. It isn't enough to simply bolt the module to the aluminum, the aluminum needs to be able to radiate the heat away and captured inside the case without metal to metal contact it will not be able to do that.
 
I'm not attaching the heatsink and module to the mopar box. I am attaching the aluminum heatsink with the module to the firewall, then the hollowed out mopar box just bolts over it to cover it. now im trying to think of how to attach the aluminum heatsink to the firewall without drilling holes in the firewall. Thought about just jb welding the heatsink to the firewall but then my idea of using thermal paste between the heatsink and firewall can't happen..
 
mopower440 said:
I'm not attaching the heatsink and module to the mopar box. I am attaching the aluminum heatsink with the module to the firewall, then the hollowed out mopar box just bolts over it to cover it. now im trying to think of how to attach the aluminum heatsink to the firewall without drilling holes in the firewall. Thought about just jb welding the heatsink to the firewall but then my idea of using thermal paste between the heatsink and firewall can't happen..
Click to expand...

I understand the current plan, but let me run something by you.
If you have a heatsink for the ECU you don't have to mount the ECU to the firewall.
You can leave the ECU and heatsink floating so to speak. (as long as you have a ground wire for the ECU it does not have to be mounted to metal.)
You could also use the firewall as a heatsink and ground and mount the ECU with the thermal compound between them.

Just some possibilities that I didn't know if you had thought of yet.
 
TrailBeast said:
I understand the current plan, but let me run something by you.
If you have a heatsink for the ECU you don't have to mount the ECU to the firewall.
You can leave the ECU and heatsink floating so to speak. (as long as you have a ground wire for the ECU it does not have to be mounted to metal.)
You could also use the firewall as a heatsink and ground and mount the ECU with the thermal compound between them.

Just some possibilities that I didn't know if you had thought of yet.
Click to expand...

Well, do you think the heatsink I have will be enough by itself? Its 1/8 thick aluminum. And is about 3/4 the size of the front of the original mopar box. Look previously in this post for pics of it, only I ended up using just the one piece instead of stacking. The 2..
 
mopower440 said:
Well, do you think the heatsink I have will be enough by itself? Its 1/8 thick aluminum. And is about 3/4 the size of the front of the original mopar box. Look previously in this post for pics of it, only I ended up using just the one piece instead of stacking. The 2..
Click to expand...

Of course it will be enough.
The ones I use in my HEI kits are only exactly as big as the ECU and 1/8 thick and never had a failure.
Gotta keep in mind that these things ran at 200+ degrees all day long inside the distributors.
 
I got the parts from the junkyard to do the HEI conversion, got the 8 pin module that trail beast recommends. I rigged it all up to make sure it all worked and it did. I decided that i wanted to gut the original mopar box and hide the HEI in it and just use the original mopar plug and all so it looked original. Well, got it all done and it wont spark. Should have known it wouldnt work with my stupid luck. Theres no reason for it not to work but it wont. I even ran a jumper from the negative post on the battery to the module ground to make sure it is properly grounded.. Just really dont understand why it wont work through the factory wiring and plug.. pisses me off as ive been wanting to get this done for a month and finally do and it aint gonna work!
 
i swapped out the module and it now works. Starts up and runs fine, BUT, the spark is NO stronger than what the mopar box could do. If i undo the coil wire at the distributor and have someone crank the engine over, it only produces a yellow spark and i can only get the cable about an inch away from the block before the spark dissapears. From past GM experience, and from watching trailbeasts video, this thing should produce a blue spark and be able to jump MANY inches to ground...any ideas..?
 
HMMM, ok, so after i got it all up and running through the mopar wiring and plug and the module mounted and hidden inside the mopar box, i decided to go in the house to use the bathroom and think about why the spark is so weak..I come back out and she wont start! I pull the coil wire and no spark!! Damn, thought i burned up this module also, but its not! I took the first module, that i THOUGHT was burned up and rigged it all up like i did the first time when i brought it home from the junkyard and BOOM!, Big fat lightning bolt spark like in trailbeasts video! SO, the problem seems to be the length of wire. For some reason, if i run it through all that original mopar wiring, it aint got enough to fire it and the few times it did, it was a very weak yellow spark. Yes, this obviously makes no sense because trailbeast had some length to his wires also, but on my pig, it wont work. I dont understand it and it makes me mad after digging all the guts out of the mopar box and having the box painted up and fabricating an aluminum heatsink for it and all, really makes me mad. I guess now if i want to run the GM crap i will have to buy that little mount that guy sells that mounts the module right up under the distributor so the wiring doesnt have to be very far. Again that sucks because that mount he sells is for the 4 pin module and i have already bought 2 of the 8 pin modules. Just dont understand..
 
well, ive narrowed it down to either the Plug that goes into the mopar ignition box, OR, the pins on the box itself that the plug plugs in to.. I can get it running and wiggle the plug a bunch and make it die. When the engine dies i will have to wiggle the plug more to get it to start back up..I have another plug with the wires attached and tried it and its way worse, just barely touch it and it kills the engine. The original plug is hard to figure out which wire is killing it because i can wiggle them individual, or all together and sometimes it wont kill it and sometimes it will. No certain way to wiggle it or anything, i can just keep on messing with the plug for several minutes and sometimes it will kill it and sometimes it will, and again, way more sensitive with the other plug i tried..so, hard to say weather its the plug or the terminals on the mopar box itself..
 
Are you going to gut the ballast resistor, and run a 14 gage jumper wire inside the ceramic and put it back on the car this way it looks stock, or just a pair of male spades and a wire.

I think hiding the jumper inside the resistor ceramic would go along with what your doing hiding the GM module in the mopar box.

I am going to run my GM module inside the car pinned thru the bulkhead connector. Theres a few extra cavity holes that are unused in my bulkhead so i might as well use them.

Great idea. Perfect upgrade for factory electronic ignition cars.
 
BillGrissom said:
Pompis,
Very useful info. Those Chinese are clever fakers, and are good at putting lip-stick on a pig. Somebody (273?) posted a photo of an MSD box that was empty inside, save for a little HEI module. ... They even go so far as to laser engrave fake SN's.
Click to expand...
and it was the SAME fake SN...so if you ever get a MSD with a SN of 682013, you got scammed.. and the fakes DIDNT have torx screws on any of the terminal blocks. That video is pretty hard to dispute if all they did was change the ignition.

The 8 pin HEI's are overkill, Use the old ones as you dont have a computer to control timing events. just a reminder diagram...Dont mind the Ford call outs....
hei.gif
 
Coming in way late to the game. My orange box is bad. Going to replace it with a cheapy from O'Reilly just to drive and looking into this. @TrailBeast are you still running this? It looks like it's not that hard to do, just wire the 4 pins on the HEI unit to the corresponding 4 pins in the Mopar box, right? I replaced my coil with one from Rev N Nator (originally planned on going that route). If I do HEI, can their coil be used or do I have to do something else?
 
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I just used the coil from a 1990 chevy truck that had a 350 in it. along with the8 pin module from that truck. But as stated above, you can use the older style module also..
 
mopower440 said:
I just used the coil from a 1990 chevy truck that had a 350 in it. along with the8 pin module from that truck. But as stated above, you can use the older style module also..
Click to expand...

Ok yeah I'd like to do the four plug and keep it in the orange box. Rereading your experience, did you end up keeping your setup in the orange box or what did you settle with?

If I use a cylinder coil, is it no longer hei?
 
ya, i gutted the mopar box, and hid the GM module inside it. The only way you can tell its not the real mopar system is the GM coil. Im not sure as far as a cylinder type coil what you can use and it still be HEI?
 
Ok. I'll have to look closely how the guys in here ran the four pins on the gm module to the pins on the orange box. How long you had it set up? Any issues? Run better?
 
I did it about 2 years ago. No problems so far. It starts way easier is the biggest thing. This thing has always been finicky about starting cold..either it didnt get enough fuel or it was flooded and had to pull and dry all the plugs. So far, its 100% better with this ignition. Like i said, it always took a lot of pumps of the throttle to get her started, but if you went a hair over what it needed, it flooded..not now!
 
a coil from a ram or dakota with a 5.2 or 5.9 hei will work as an hei coil in place of the GM hei coil to keep it looking mopar,,remember to delete the balist resistor for a full 12 volts,gettign ready to do this on my mopar street rod
 
jrc4y4 said:
Coming in way late to the game. My orange box is bad. Going to replace it with a cheapy from O'Reilly just to drive and looking into this. @TrailBeast are you still running this? It looks like it's not that hard to do, just wire the 4 pins on the HEI unit to the corresponding 4 pins in the Mopar box, right? I replaced my coil with one from Rev N Nator (originally planned on going that route). If I do HEI, can their coil be used or do I have to do something else?
Click to expand...

5 years with the same 8 pin module replacing the Mopar box and the matching E core coil with ZERO issues.
Some of the canister coils (Like the Pertronics Flamethrower) can come close, but the E and C core coils are usually a hotter spark.
I have also put the HEI module inside a Mopar box and it works fine, but using the Mopar case as a heatsink is mandatory if the module doesn't already have one.
Heatsink compound (like computers use for the processor) is a REALLY good idea also.

Here's the one I did using an 8 pin module, (which has advantages over the four pin) and you will notice the screws for the diode stick up more than a stock unit, as I didn't want the screws to look modified.
This was to keep the look but the insides had to be removed to make room for the HEI module so the screws come though farther.
The second pic is not the one I did.
I just used that pic for the wire connection points.
Whoever did that one sucks at soldering.:D

stockerHEI.jpg


HEI.jpg
 
Ok, thanks for all the info. Thanks for the wiring showing Trailbeast. I plan to run a 4 pin just because I can do it for free. Are you guys running vacuum advance? I capped mine off years ago and it's always ran well without it. Good idea on the Mopar coil.

I'm ordering a chrome box today to get my car back and running normal again and will do this project at my leisure.
 
The second pic is not the one I did.
I just used that pic for the wire connection points.
Whoever did that one sucks at soldering.:D

Hey Trailbeast this is what I have so far. All 4 prongs on the GM HEI module have a letter (might have to blow up the pic to see). I want to make sure I wire this correctly. This is what it looks like I need to do. Correct me if I am wrong. So B goes to 3. C goes to 4. W (the big pin) goes to 1. G goes to 2.

Also, I hollowed out the BACK of my ballast resistor. I plan to run a wire between the two prongs in addition to what is there, essentially eliminating it. So my factory wiring will still plug in on the front, it'll look stock, but won't be functioning. Is this ok? Am I understanding this correctly?

So I can use that heat compound on the side between the HEI and the ignition box and that is enough heat sink? Stuff like this? Super Lube 3 oz. Tube Heat Sink Compound-98003 - The Home Depot
Do I need to ground it, if so, where/how? And do I have to make a bracket to go under this thing or can I bolt it back onto the apron? Can I leave the HEI "floating" only attached by the soldered wires, or do I need to actually mount it in the box? Thanks for the help you guys.

ICM1.JPG


Box.JPG


ballast.JPG
 
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