Why do the ignition boxes fail?

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Mr. Sinister said:
No
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Ah sorry I didn’t read all of the prior post from old man Mopar. Thanks! Yeah since I’m not at the car I’m basically relaying any of my research to my dad. He’s meticulous in his dealings but never hurts to get as much info as you can. Thank you!
 

THIS IS THE REASON i BOUGHT 4 0R 5 OR EACH COMPONENT 15 YEARS AGO , EVEN THEN PARTS WERE HIT OR MISS . SO FAR ALL THE PARTS WORK WELL HAVE ONLY CHANGED 2 VOLTAGE REGULATORS AND 2 IGNIYION BOXES SO FAR
 
MadScientistMat said:
I would be interested in trying an autopsy if anyone wants to send me a dead ignition module. My guess is that the original power transistor is no longer made and they've either grabbed a different part that didn't quite meet a key specification, or resorted to chip brokers who buy up obsolete parts but sometimes grab batches that haven't been stored properly (or worse).
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1974 Brain Box saves the day.

Was heading out to a local car gathering a couple weeks ago, and a no start on my '76 Truck. Turns out the 1 year old replacement brain box failed. I had a well used 1974 5 pin brain box from my '74 Dart that I had replaced because all the goo on the back had melted out from the hot sun in...
www.forabodiesonly.com
 
jrc4y4 said:
My dad is babysitting my Scamp since I’m out of the US. Just heard my 10 year old American chrome box failed. Why are these ignition boxes prone to failure? I’ve had two orange boxes and a chrome box fail since 2004. 2/3 of them were American made. I think I may hollow out a box and do the hidden HEI trick finally. But still curious, what is it about them that cause failure?

View attachment 1716405594
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My thought is the same problem that makes 30+ year old PCMs fail, old capacitors. Bad grounds and and using high output alternators also comes to mind.
 
I would think that using modern HEI electronics would be a pretty easy and attractive option compared to hunting for 50 years old ignition boxes or using poorly made Chinese crap Mopar reproductions.

I think the HEI stuff is designed to be close to the distributor, but folks seem to have success mounting them in hollowed out old Mopar boxes. I’m surprised some body isn’t making those and selling them.
 
Mike69cuda said:
I would think that using modern HEI electronics would be a pretty easy and attractive option compared to hunting for 50 years old ignition boxes or using poorly made Chinese crap Mopar reproductions.

I think the HEI stuff is designed to be close to the distributor, but folks seem to have success mounting them in hollowed out old Mopar boxes. I’m surprised some body isn’t making those and selling them.
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I wonder if GM HEI modules made now aren't much better than any other component produced nowdays. Their modules are cool because they are 12 volt and don't require a ballast. Otherwise the Mopar electronic ign. works well. Failures now days seem to be bad newly produced components or something yo do with 50 year old wiring. Want somehing simple? Put a Pertronix 1 in a stock distributor. If you have a serious race car, use a MSD but I wouldn't run one on the street.
 
Kern Dog said:
I burned out a High Rev in my Charger.

View attachment 1716405918

View attachment 1716405919

I had the 1.4 ohm coil and the .70 Ballast resistor.

View attachment 1716405920

The instructions with the distributor, Hi Rev ECM and ballast:

View attachment 1716405922

I have had crappy luck with ECMs though. Last year I was dealing with a battery that would drop voltage. The battery would be okay to start the engine but it had me wondering if (when running and recharging the battery) the charging system somehow wreaked havoc with the ignition system. I wasn't sure if the ignition system was sensitive to the voltage fluctuations.
I admit to being borderline clueless to electrical matters sometimes.
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Not saying this was a problem but it looks like your grounding washer is on the wrong side of the connector eyelet.
 
RustyRatRod said:
Mainly because, as we all know, the resistance those resistors give goes down as they heat up, so a .5 ohm for example might give .2 or even .1 when it's hot.
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I'm pretty sure the resistance goes up as they heat up. Maybe someone else can verify. @halifaxhops
 
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Mike69cuda said:
I would think that using modern HEI electronics would be a pretty easy and attractive option compared to hunting for 50 years old ignition boxes or using poorly made Chinese crap Mopar reproductions.

I think the HEI stuff is designed to be close to the distributor, but folks seem to have success mounting them in hollowed out old Mopar boxes. I’m surprised some body isn’t making those and selling them.
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I also am surprised someone isn’t selling them already in an old Mopar box. That said, I plan to do that at some point just on my own car.
 
jrc4y4 said:
I also am surprised someone isn’t selling them already in an old Mopar box. That said, I plan to do that at some point just on my own car.
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There appear to be a few examples out there

HEI modules also aren't immune to corner cutting these days, though.
 
wonder if this one has a proper transistor
Módulo encendido electrónico Simca, Talbot Lucas DAB951 - Recambios Pro//M

European part numbers for chrysler ignition module mid 70s until 1979

PM00180
CARGO 150029
CHRYSLER 3874020
CHRYSLER 3656128
CHRYSLER 3438850
LUCAS DAB951
QH XEI1
TRANSPO CM900
TRANSPO CM390


look at this, later unit used on chrysler peugeot talbot simca and Euro Dodge from 1979-1986
New Hella Mopar Ignition Module Talbot Horizon Simca Rancho Solara Matra Alpine Dodge Chrysler 5da006623-301 5206390 3874020 52209060 - Etsy UK

has some super extra heatsink stuck on it, you'd need an Omni/horizon loom connector to connect it

Or
orginal 5 pin black modules by the look of things, US based business closing make the man an offer
Parts

Dave
 
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Keep in mind that there is likely nothing wrong with the newer smaller transistors. It is crappy construction and lack of effective heat sinks that kill them.

Remember cell phones from 30 years ago? Nobody thinks bag phones worked better or wants to go back to them. Electronic components keep getting smaller, faster, better.
 
Someone posted pictures of the deteriorated ECU guts a while back.
It looks real bad.
I don't have that picture.
 
Hyper_pak said:
Someone posted pictures of the deteriorated ECU guts a while back.
It looks real bad.
I don't have that picture.
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I saw a photo of one still bolted to the firewall with the potting material trailing out. Dang if I saved it.
 
The topic here is an interesting one and I wish that there were a smoking gun to blame. There are theories and some evidence worth considering but so far I have not seen a clear reason for failure other than mismatched components.
I have a 75 Power Wagon that has only barfed a ballast resistor once. In the 12 years I've owned it, I've never touched the stock ECM. I have a 72 Duster that I converted to 1973-76 A body wiring with factory electronic ignition and it too has been reliable, same with the conversion I did to my Jigsaw Charger. My 67 Dart has points ignition and I haven't changed the points in 20 years. Granted, these cars don't see more than 1000 miles a year collectively.
My red Charger also has a conversion to factory style electronic ignition and it gets driven the most. It has had numerous ECM failures and I've tried several. I had a Rev-N-Nator but pulled it to sell. I had an FBO box that made my tach needle bounce so I pulled it. I've used new MP Chrome boxes, Orange boxes, an Ehrenberg Hi Rev 7500 and puked all three. My coil is an Accel that measures 1.3 to 1.4 ohms but I admit, until recently I used whatever 2 spade ballast resistor that I had without knowing the rating. For me, maybe the ballast resistor was to blame for previous failures but I'll never know for certain.
The idea of using that GM HEI module is interesting, especially when hidden behind a Mopar ECM case. I have several ECMs here that I could tinker with to see if I could make the HEI module work.
 
Kern Dog said:
The topic here is an interesting one and I wish that there were a smoking gun to blame. There are theories and some evidence worth considering but so far I have not seen a clear reason for failure other than mismatched components.
I have a 75 Power Wagon that has only barfed a ballast resistor once. In the 12 years I've owned it, I've never touched the stock ECM. I have a 72 Duster that I converted to 1973-76 A body wiring with factory electronic ignition and it too has been reliable, same with the conversion I did to my Jigsaw Charger. My 67 Dart has points ignition and I haven't changed the points in 20 years. Granted, these cars don't see more than 1000 miles a year collectively.
My red Charger also has a conversion to factory style electronic ignition and it gets driven the most. It has had numerous ECM failures and I've tried several. I had a Rev-N-Nator but pulled it to sell. I had an FBO box that made my tach needle bounce so I pulled it. I've used new MP Chrome boxes, Orange boxes, an Ehrenberg Hi Rev 7500 and puked all three. My coil is an Accel that measures 1.3 to 1.4 ohms but I admit, until recently I used whatever 2 spade ballast resistor that I had without knowing the rating. For me, maybe the ballast resistor was to blame for previous failures but I'll never know for certain.
The idea of using that GM HEI module is interesting, especially when hidden behind a Mopar ECM case. I have several ECMs here that I could tinker with to see if I could make the HEI module work.
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If I read you correct, you use the basic ballast on a Accel Super coil. They take two. I have one on my 70 340 for over 35 years and never had an issue. Don't remember what the suggested ohms are, but I do have the paperwork somewhere. It came with the added ballast in the package. I just changed my duel point 69' 340 points, that had over 60,000 miles on them. Points still good, but the rubbing block showed a little wear.
 
Swinger 340 said:
If I read you correct, you use the basic ballast on a Accel Super coil. They take two.
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They take two what ? Two ballast resistors?
I don't think this is the "Super" version....

Coil 3.jpg


Coil 4.jpg


Isn't the "Super" shaped like this:

1747810039325.png
 
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