HEI in Mopar ECU casing

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I bought some cheap amplifier boards (LM3886) from HK, and they were fakes, left negative feedback. The seller complained bitterly and said he checked with his supplier and was guaranteed that they were genuine parts and they only sold genuine parts. All the components were fake.
I hear that the aircraft industry is very concerned about this as they can't tell the fake from real.
 
I've been emptying a couple of Mopar ECU cases lately aswell, but my 'torching-skills' had deformed / melted the plastic pins of the plug, so I had to forget about that conversion for awhile.

Instead I mounted a module on a computer CPU cooling block.
But I never was able to get the engine actually running with this module. Probably a bad one.
I borrowed another module from a friend and the engine fired up instantly, but did that only once. 2nd time starting it didn't even give a kick anymore.

After fumbling around for awhile with these modules I simply gave up for the time being and switched back to the chrome ECU.


IMG_2789_zps2ad8cfad.jpg
 
I don't see a ground wire. The module MUST be grounded at the mounting bolts. These HEI modules are fairly dependable. I first discovered when I put the Toyota 20R into my (now gone) Cletrac, and run one on my 67 Dart. Didn't even use a separate heat sink. Someone had mounted a Mopar conversion with a sheet metal screw onto the firewall behind the dist, so I used on of those holes
 
I took the pic when I had just taken the module out of the car again. Groundwire is still in the car.
There was still some amount of heatsink compound left on the CPU cooler, but the module never even got as much as a slightly warm as it couldn't get the engine running at all.
 
Loved the fake transistor. Did you reuse this feature? I sure would have!

Wanted to add my 2 cents about cleaning out the potting from these boxes. I have had good luck with heating the entire assembly in an oven and digging out the softened bits with a pick.
 
Jaguar was doing this in the 80's with their ignition modules. I had just tested one bad for a customer and for the fun of it undid the four screws holding the top on and found a four terminal GM HEI module inside. It even had the GM logo on it. I told the customer I could order the Jag. unit for $200+ and wait a couple days to get, or a $20 GM module sitting on the shelf. Can you guess which one he picked?
 
BigBlockMopar said:
I took the pic when I had just taken the module out of the car again. Groundwire is still in the car.
There was still some amount of heatsink compound left on the CPU cooler, but the module never even got as much as a slightly warm as it couldn't get the engine running at all.
Click to expand...


Voltage spikes can also kill these things quick. I always run a relay when installing HEI in my cars,never had any trouble with a module.
 
BigBlockMopar try a regular solder pen instead of a gas torch. It's easier and it will not melt the pins.

Gryzynx I will use the fake transistor because I want to keep the ECU to look like a stock ECU. Going to paint the casing black then put a decal like this on the casing.

ElectronicIgnition_zps494fad12.png
 
Does anyone here know what the Voltage output requirements are to trigger any of the more than 30 different "GM" 4 pin modules? Does anyone know what the output of the at least 20 different Mopar Magnetic Pick-Up's are? Why would anyone go through all this and not even know what the output of the module is, the trigger signal requirements or the RPM limits?
Just because it's called a "HEI" doesn't make it work any better when combined with all the wrong components.

We've tested probably 10,000 GM HEI modules from manufacturers in probably 20 countries over 40 years, some work OK and most work no better than a Mopar stock ECU. Some of the Performance Modules are better but sure not the end all.

The correct coil for the module is extremely important, the voltage signal and ambient tempuratures are critical.

Will they work and run the motor.... in most cases yes, but I can wire up a Golf Cart to run on a Mopar or GM module. Give me a Voltage Signal from a pick-up of somekind and a coil and I'll make it run. Mopar, Duraspark, GM HEI stock modules are all 1970's technology, it's 2013, we have color TV's and phones without wires.
 
cuda66273 said:
Does anyone here know what the Voltage output requirements are to trigger any of the more than 30 different "GM" 4 pin modules? Does anyone know what the output of the at least 20 different Mopar Magnetic Pick-Up's are? Why would anyone go through all this and not even know what the output of the module is, the trigger signal requirements or the RPM limits?
Just because it's called a "HEI" doesn't make it work any better when combined with all the wrong components.

We've tested probably 10,000 GM HEI modules from manufacturers in probably 20 countries over 40 years, some work OK and most work no better than a Mopar stock ECU. Some of the Performance Modules are better but sure not the end all.

The correct coil for the module is extremely important, the voltage signal and ambient tempuratures are critical.

Will they work and run the motor.... in most cases yes, but I can wire up a Golf Cart to run on a Mopar or GM module. Give me a Voltage Signal from a pick-up of somekind and a coil and I'll make it run. Mopar, Duraspark, GM HEI stock modules are all 1970's technology, it's 2013, we have color TV's and phones without wires.
Click to expand...

"The Mopar system uses the positive temperature coefficient of the ballast resistor to regulate the primary coil current with changes in duty cycle (engine rpm). A simple, relatively reliable system for most daily drivers. The disadvantage with the ballast resistor is the slow response time of the resistor resulting in the field of the coil not being fully charged during sudden acceleration ie, a spark that may not be as hot as is possible with more modern systems. The GM HEI module is typically based upon a Motorola (now Freescale) MC3334 IC or equivalent. The MC3334 regulates coil current using an internal variable voltage reference. This internal variable voltage reference is able to respond much faster to changes in duty cycle resulting in a much hotter spark durring times of sudden acceleration and less destructive heating to the coil during low rpm operation. The MC3334 also imposes a 1 msec off time to ensure complete discharge of the coil field during a spark event. At very high rpms coil current is limited due to the slope of the coil's primary charging ramp time which is determined by VBatt and the primary impedance of the coil itself. Some good OEM coils are the Ford "E" core coils and the remote GM coil which is also an "E" core design. The MSD Blaster line of aftermarket coils are also very good coils. Don't be fooled by claims of HIGH VOLTAGE from the perveyors of coils. The voltage developed by the coil will only be as high as the break-over voltage of the plug firing, typically only a few thousand volts. When shopping for coils it is important to look for a coil with a high Joules rating and match the rpm range to your needs. If the coil manufacturer does not publish the joules rating of the coil, walk away and buy somewhere else. Don't use a race only coil on the street. It will just overheat and fail."


http://www.slantsix.org/forum/viewtopic.php?p=98527&highlight=#98527
 
cuda66273 said:
We've tested probably 10,000 GM HEI modules from manufacturers in probably 20 countries over 40 years,
Click to expand...

Now you're just coming across as a TV preacher.

Here's what I know.

1--I'm not spending 300 bucks or more on MSD or anything else

2--The parts store quality of Mopar ECUs is terrible, is not predictable, and I've got about 20 boxes out of junkers here that have "some use." Some work, some don't and several have issues such as potting material disintegration.

3--I find your claims about your box to be unbelievable. I frankly doubt on the face of it that you've actually tested 10,000 any kind of modules.

4--I've run a GM module on my old Toyota / Cletrac for several years with no issues, and a GM has been in the Dart now for more than two years, I drive this thing every day the weather permits. It always fires right up, and gives me no trouble.

5--If I need a replacement, I can get one at any parts store

6--Your constant comments about this indicate insecurity as well as an agressive attitude against people you aren't gonna convince. If you want to advertise, pay the site and "get a banner."
 
cuda66273 said:
Does anyone here know what the Voltage output requirements are to trigger any of the more than 30 different "GM" 4 pin modules? Does anyone know what the output of the at least 20 different Mopar Magnetic Pick-Up's are? .
Click to expand...

Magnetic pick-ups are variable reluctance. The output varies with RPM, at cranking of 200 RPM a few volts, at 6,000 RPM perhaps up to 100V. The Mopar design is single pole at the coil, the GM has multiple poles in alignment, with a coil in the complete magnetic circuit. The GM system has advantages. There is significant spark scatter in the Mopar system, the reluctor has a small radius, shallow teeth, so run-out is a problem. The specs are not much better than points, but no points or rubbing block wear. Run-out errors are eliminated in the GM with the multiple poles.

The attached picture shows a VR signal the top trace and decode output on the bottom. A disadvantage in a VR sensor is, the amplitude changes the operate point to a small degree.
 

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Nirvana and Kit Carlson, nice work and good info!

I'm cranking up the thanks for both of you.


SSD would have been all over this. Kinda miss the bearded guy.
 
Gryzynx said:
Nirvana and Kit Carlson, nice work and good info!

I'm cranking up the thanks for both of you.


SSD would have been all over this. Kinda miss the bearded guy.
Click to expand...

It was copy and paste on my part,with a link to the original thread. I know the info now,but I learned it from that post, so I saved myself some typing. I didn't realize it was the dude from FBO, I feel sorry for anyone who buys into that crap.:wack:
 
I've got the HEI module today. Next thing is to make the mounting bracket but the problem is to have my boss bend the mounting bracket for me. Since I dont understand how to program a press brake.

DSC_2035_zps0e8db330.jpg
 
This is how the module will sit in the casing. Can't wait to see it finished and also test it!

DSC_2039_zpsd673c996.jpg
 
Pompis said:
This is how the module will sit in the casing. Can't wait to see it finished and also test it!
You need to put the silicone on the flat plate and turn the module over so the plate will transfer heat into the housing. QUOTE]
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X2. The way you have it shown, there's no heat sink. I think I'd try and mount a small aluminum sink (flat aluminum) in the bottom of the box
 
Could be wrong, but I think he is planning to mount it to a sheet metal stand this will work as a heat sink. He mentioned something about not knowing how to run a press brake. If so, he will probably bolt the module to the stand and then bolt the Mopar ECU shell over it like a cover.

That's my guess anyway.
 
Del has a good point about the top of case and aluminum.

An aluminum heatsink is about 4x better in thermal conductivity than steel.
http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html
A heatsink relies on surface area exposed to air. That is why heatsinks have fins. The thickness of a heatsink is designed to carry heat away along the heatsink, otherwise a temperature gradiant across the heatsink makes it less effective.

Another important consideration is the module ground connection. It might best be be done with a ring terminal jumper connected directly on a module mounting terminal, to avoid a dissimilar metal connection if aluminum is used.

I would guess the heatsink requirement to be 10 to 30W. The module maximum temperature is likely less than 125C. I can do an estimate of size, but much depends on abient temperate and airflow.
 
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