Help Junkyard coil for HEI distributor?

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macdrew77

macdrew77

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So after weeks of valvetrain and intake problems keeping me from finally driving my Dart I thought I finally had her ready to go. Crank crank crank no fire. So I test the coil several different ways and nothing. This thing came with a Chinese HE I distributor thing and some sort of coil (someone said it was a Ford product, pic included.)

So I'm wondering if there's a good source of coils I could find at my local pick a part and finally get this baby on the road.
 

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Those connections are the standard Chevy/GM ecore style that the 7 pin modules use.
You should be able to find those all over the place on 98-2006 or so Chev and GM V6 and V8 trucks.

The outside of yours has been dressed up a little, so they look slightly different but exactly the same thing with different mounting.
They will plug right in just like yours.

P.S. Is that your tank vent right under it? :D
 
That is a 5.0 Ford E-core coil. They are about $20 at auto parts stores. If you want fancy colors, marketing hype, then pay 2x to 3 x more.

But are you sure the coil is bad? It could be something else. Got 12V at red wire? Have you put a plug on coil wire and checked for spark while cranking? There are more tests if you would like to learn to trouble shoot.
 
Ford and GM both use that exact same coil but with different mounting brackets.
 
KitCarlson said:
That is a 5.0 Ford E-core coil. They are about $20 at auto parts stores. If you want fancy colors, marketing hype, then pay 2x to 3 x more.

But are you sure the coil is bad? It could be something else. Got 12V at red wire? Have you put a plug on coil wire and checked for spark while cranking? There are more tests if you would like to learn to trouble shoot.
Click to expand...

x2 and the $20 coil works just fine.
 
TrailBeast sure knows his stuff. I think Ford calls their ignition "TFI". Easiest to stay w/ that since you have a nicely wired connector. For others, the GM HEI "external coil" (85-95 V-8 ) is nice and gives a tach output wire. You could even use a Mopar Magnum coil (92-00?) if totally loyal. It bolts to the front of the engine.

Elaborate on how you determined "bad coil". Kit and I wonder since those look very rugged. But, I did have the similar e-core coil-pack in my 2002 3.8L Chrysler fail. I got no flashing with a clamp-on timing light over the 2 plug wires of the coil closest to the engine (hottest) and could hear a faint clicking inside. A new one fixed that.
 
So got the new coil in...same problem. No spark. It seems the old coil wasn't the problem, or at least wasn't the only problem. To test the old coil I hooked up a spark plug to the coil, grounded the coil and then grounded the negative wire coming from the coil and there was no spark to the plug.
So after buying a new coil and seeing the same result I went ahead and bought a new GM hei ign module. Hooked it up and same problem. No spark. My original module had 4 pins all in line with each other, where the gm module has 2 pins on each side. Are all hei module interchangeable if they have the same number of pins? Also the physical size of the modules was sligihtly different, so I'm not sure it was properly grounded when I tested it.
So my next move is going to be picking up a new multi meter and testing the pick up coil to see if it's good. This is a Chinese hei knockoff dist I believe, any idea on what reading to expect? If the coil pickup checks out I will be reinstalling the module with a ground wire attached and see if there's any difference. If anyone has any other advice they feel like passing on, it's more than welcome. I am so close to driving my Dart but so far...
 
Also I am getting 12v to both sides of the coil (via test light). Normal? Not normal? Thanks
 
Here are a few pointers.
When you say you grounded coil, I assume you bolted down the aluminum mount. While that is good, it is insulated and has no effect on coil operation.

Without current limit the coil can be damaged! The ignition module has that, it limits the current to about 5A. It also limits the current by controlling the time it pulls the negative lead low to energize the coil. When the negative lead is released by module, the spark happens. The damage danger: it only takes about 3ms to charge the coil fully. In the long term the only current limit in coil is the resistance, that is about 0.5 Ohms. At 12V, the current would be 24A, in a fraction of a second. Since human reaction is typically 50ms, that is 0.05 seconds. So if you want to test, be quick, and touching the negative lead can be a shocking experience.

If both +, - leads of coil have 12V, that means there is zero volts across the coil, when you ground the - lead, the coil is energized. The time it takes for you to measure, the voltage is enough to burn a coil. So, are you sure you have a good ground for your test, and plug grounded?

Others may be able to help with module pin connections.
 
Ok, which module do you have of these 5?
 

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Sounds like he "originally" has one of the Chinese / down under "white" import "ready to run" distributors. I did not pay attention, I think these use a Holden module or some such

OP: We need piccures.

Also, I remember "vaguely that some of those coils can fool you. You need to make certain which terminal of the coil you are actually hooking to

In the example below:

coil_and_wiring.jpg


The top two terminals are the same as the bottom two. In other words you do NOT hook to one top and one bottom terminal.........you hook to EITHER the top two or the bottom two.

If you are trying to use the older 4 pin GM HEI this is the wiring. Module MUST be "flat mounted" for heat to a sink and MUST be grounded through the two screws

attachment.php
 
What I don't get is why he has a "ready to run" AND mentions module connections.
Makes me wonder if he's trying to hook a module to a module or something.

Here is the 8 pin diagram as well.
 

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Well LOL "you might remember" that a member chewed my *** the other night and all I was trying to get across is "we need more info."
 
67Dart273 said:
Well LOL "you might remember" that a member chewed my *** the other night and all I was trying to get across is "we need more info."
Click to expand...

I don't think I saw that, but more info would be nice.
When I have the time I can help here and there, but if I can't get the information I need to help I just say F it and let em figure it out, (or not) whatever.
Of course I realize people have stuff to do outside of FABO as do I. :D
 
TrailBeast said:
Ford and GM both use that exact same coil but with different mounting brackets.
Click to expand...

Yup. We sell the Accel replacements at work and that's all that's different. The electrical connections are even the same.
 
It is very similar to the one 67Dart posted. Pic included. I took out the module so I could try and determine if the problem was in the dist. First pic is new GM module installed in with A jumper because it's not a great fit. Second pic is old module came with dist.
 

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The photo of the GM one you posted should wire up like the diagram I posted. This is what I call the "older 4 wire" it is the oldest, "original" GM. That should work if the dist. is good, the module is good, and it is all wired up OK
 
KitCarlson said:
... The damage danger: it only takes about 3ms to charge the coil fully. In the long term the only current limit in coil is the resistance, that is about 0.5 Ohms. At 12V, the current would be 24A, in a fraction of a second. Since human reaction is typically 50ms, that is 0.05 seconds. So if you want to test, be quick ...
Click to expand...
If true, then I would have damaged a lot of coils (but didn't). I usually ground the negative lead for >1 sec before releasing (thus getting a spark). If 24A flows, the primary coil dissipates 288 W of heat (assuming a full 12 V on coil+). This will overheat it, but it takes minutes. For comparison, a hair dryer is ~1000 W. In continuous running, you do need to limit the recharging time between each spark (i.e. "dwell"), which HEI modules do with smart electronics, and most coils only need 10 msec or so to charge up. The 1970's Mopar ECU's were just a transistor w/ no smarts so didn't limit dwell time and thus still needed a ballast resistor as a kludge, as did the earlier points.

I suspect that the P.O.'s coil test failed because he didn't ground the body (or electrode) of the spark plug he was using. Most official spark testers come w/ an alligator clip to attach it to BATT- (or engine block). The later "HEI distributor doesn't work" conclusion might have been from using the HEI distributor plus an external HEI module, as TrailBeast was smart to ponder that possible FU. The ready-to-run HEI distributor has an internal HEI module, so doesn't need or want an external module. You wire it straight to the coil (hence the name). I don't know where they source that HEI module. It is different than GM's 4-pin one, but probably functionally equivalent. No reason you couldn't install a GM one if you could work it under the cover. I plan to install the better GM 8-pin and hack openings in the cover for it (or since I got a milling machine, maybe purty holes).
 
BillGrissom said:
I suspect that the P.O.'s coil test failed because he didn't ground the body (or electrode) of the spark plug he was using. Most official spark testers come w/ an alligator clip to attach it to BATT- (or engine block). The later "HEI distributor doesn't work" conclusion might have been from using the HEI distributor plus an external HEI module, as TrailBeast was smart to ponder that possible FU. The ready-to-run HEI distributor has an internal HEI module, so doesn't need or want an external module.
Click to expand...

For testing the spark plug body had copper wire twisted around leading straight to the battery negative. I managed to shock myself, but no spark so I just went to the parts store for a new coil as cheap assurance. I unscrewed the cover of my distributor and swappped the module for the GM one. I have the dist and the e core coil, no other modules.
 
BillGrissom said:
If true, then I would have damaged a lot of coils (but didn't). I usually ground the negative lead for >1 sec before releasing (thus getting a spark). If 24A flows, the primary coil dissipates 288 W of heat (assuming a full 12 V on coil+). This will overheat it, but it takes minutes. For comparison, a hair dryer is ~1000 W.
Click to expand...

The ability of an epoxy potted coil to expel heat is not very good. Normal current is about 5A, Watts increases as current squared. At 5A, 12.5W, at 24A 288W, about 23x. In my ignitions I shut off power to coil in 0.2s for loss of trigger pulses, with good reason. It just takes burned enamel on a single winding turn to create a fault. There is no magic oil healing, like in can coil. It will take less than a second to reach 24A, if the plug is not connected, the flash over internal to the coil will render the coil limited from original capability. It can also be a lethal shock, at primary or secondary.
 
To test this coil, just :
1) Make sure 12v is on the proper primary side terminal
2) Connect a jumper to the other primary side terminal, and, while being careful to not touch the other end, just touch that other end for a fraction of a second to ground. The wire should make occasional brief contacts and make some decent sparks but not have long charging times.
3) Don't test at a plug, because you are adding in all the possible problems inside the distributor cap. Test at the far end of the spark wire from the coil (at the end that would normally connect to the distributor cap center post). Place it 1/4" to 3/8" from metal and watch for a good blue spark there.

OP, you need to understand that looking for a spark across a .040" spark plug gap in open air is meaningless. Jumping that small gap in open air is takes very low spark energy. It takes many times higher spark energy to fire the compressed fuel-air mixture in the engine. So that is why you test in open air to see if it will jump at least 1/4" to 3/8".
 
67Dart273 said:
Sounds like he "originally" has one of the Chinese / down under "white" import "ready to run" distributors. I did not pay attention, I think these use a Holden module or some such

OP: We need piccures.

Also, I remember "vaguely that some of those coils can fool you. You need to make certain which terminal of the coil you are actually hooking to

In the example below:

coil_and_wiring.jpg


The top two terminals are the same as the bottom two. In other words you do NOT hook to one top and one bottom terminal.........you hook to EITHER the top two or the bottom two.

If you are trying to use the older 4 pin GM HEI this is the wiring. Module MUST be "flat mounted" for heat to a sink and MUST be grounded through the two screws

attachment.php
Click to expand...

I have this same set up in my 72 Duster .I did it because the GM HEI module is much cheaper than the stock Mopar box.Although I may later mock up a 'dummy' stock Mopar ignition set up to give it the original look.The one thing I did with mine and it is VERY important is add the anti heat grease on the back of the module,and find an aluminum heat sink to attach it to and run the module to the inside of the car.These modules get hot and will burn out if they get too hot and the heat sink will keep it cool.I've had the same HEI module in my Duster for 4 years now and never had to replace it yet.
 
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