HEI conversion Dodge ram truck coil

[Zipperd]

Hello Everyone,

I saw this post by TrailBeast: Installing a GM HEI Module

This intrigued me as to how I can get a really hot spark; I drive my car on propane, so strong ignition is very important.

I was wondering if this setup with the 94-97 Dodge Ram truck coil proved to be reliable. (I read that some coils are not suited for use because they make the GM module really hot)

Because I am debating the coil he suggested or the FD478 coil mentioned in this post on a different forum: HEI Electronic Ignition Retrofit How-To - Slant Six Forum.

I am already on the GM ignition module with a round 12v-rated coil.

Warm regards from the Netherlands,

Zip

 

[George Jets]

1995 Ford F150 pickup (application) e-coil works well with the mopar HEI conversions.

Simple 2 spade + & - hookup. Runs on full 12 volt, no ballast resistor. Runs Cool, delivers hot spark.

The trick is the "E-Coil".

Rock Auto sells them, inexpensive.

Here is the handy coil lead that fits the conversion setup well.

E-bay item number >

☆☆☆☆☆

 

[George Jets]

'89 D100 with E-coil/Mopar HEI conversion.


☆☆☆☆☆

 

[TT5.9mag]

On my run stand I use a gm 4 pin hei and an e core coil from a 2001 dodge truck. It makes a nice spark.

 

[TT5.9mag]

On one of my darts I did the hei conversation using a gm 4 pin module, a stock electronic distributor, and an MSD 8202 coil. Works wonderfully.

 

[trapster]

Don't forget to re-gap your spark plugs

 

[Zipperd]

Thank you all for the nice information! So, an E coil it is! It seems like there is not much difference in which automaker brand coil you get as long as it is an E coil.
In that case, I have an E coil out of a '98 Volvo lying around; I'll go try that first!

 

[TT5.9mag]

Just make sure whatever coil you use is designed to operate on full battery voltage and it’ll work fine.

 

[Zipperd]

Incredible! Almost a 1 inch spark! Gapped the plugs to .045. Runs a bit stronger now. Although idle is still shaky, so perhaps it is not a ignition problem.

 

[Bewy]

[1] I would get a coil that has the correct primary resistance....& an E core coil. Two examples are the MSD #8207 or Summit # SUM-850500, $75 & $42 respectively from Summit.
[2] 1" spark. Sounds like that coil has a high turns ratio, which is trading voltage for current. You want a coil with high current, because it is the heat [ current ] in the spark that causes ignition.
[3] Overheating GM HEI module. The modules are internally current regulated to 5.5 amps, so they do not overheat. The only one that I am aware of that is higher is the MSD# 83647, 7.5 amps.
[4] Use 0.060" plug gaps.

 

[Zipperd]

[1] I would get a coil that has the correct primary resistance....& an E core coil. Two examples are the MSD #8207 or Summit # SUM-850500, $75 & $42 respectively from Summit.
[2] 1" spark. Sounds like that coil has a high turns ratio, which is trading voltage for current. You want a coil with high current, because it is the heat [ current ] in the spark that causes ignition.
[3] Overheating GM HEI module. The modules are internally current regulated to 5.5 amps, so they do not overheat. The only one that I am aware of that is higher is the MSD# 83647, 7.5 amps.
[4] Use 0.060" plug gaps.

What would be the correct primary resistance value?

 

[TT5.9mag]

What would be the correct primary resistance value?

Don’t overthink it too much. Any e core coil that’s designed to operate on full voltage will work. You ain’t lightin nitromethane on 50 pounds of boost. Plugs gapped at .050 and send it.

FYI the primary resistance on gm coils of the HEI era were .5-1.0. I’ve used coils with primary resistance from .32 to 1.5 without any significant difference.

 

[Bewy]

The problem is the 'significant difference', which is the current, not the voltage cannot be measured easily. That is why the coil should be matched to the ign system. The original HEI coil had a 0.6 ohm primary, so a coil around 0.4-0.6 ohm s should be used.
You can use a factory canister coil that has a 1.5 ohm primary resistance, & if it has a high turns ratio will through a long spark. Looks great, eh!!!
But the spark will be low on current, & it is the heat in the current that ignites the mixture. The spark duration is also shorter.
Use 0.060" plug gaps with good spiral wound leads. GM specified 0.080" gaps for some engines.

 

[George Jets]

Here is a good video explaining how to measure ohms resistance on the e-coils, (and other coils).

He is testing the same 1995 Ford F150 Pickup E-Coil that I use with my Mopar HEI conversions.

☆☆☆☆☆

 

[jbc426]

Hello Everyone,

I saw this post by TrailBeast: Installing a GM HEI Module

This intrigued me as to how I can get a really hot spark; I drive my car on propane, so strong ignition is very important.

I was wondering if this setup with the 94-97 Dodge Ram truck coil proved to be reliable. (I read that some coils are not suited for use because they make the GM module really hot)

Because I am debating the coil he suggested or the FD478 coil mentioned in this post on a different forum: HEI Electronic Ignition Retrofit How-To - Slant Six Forum.

I am already on the GM ignition module with a round 12v-rated coil.

Warm regards from the Netherlands,

Zip

I tried this ignition "upgrade" for my Slant 6 years ago. I used one of those brick-looking coils, but can't recall which one.(it was an Accel coil)

Another thing I did that paid off once was to mount a second HEI module right next to it. I could easily swap modules by swapping the plug. Use the gel and mount the modules on a small aluminum plate to act as a heat sink.

 

[TT5.9mag]

The problem is the 'significant difference', which is the current, not the voltage cannot be measured easily. That is why the coil should be matched to the ign system. The original HEI coil had a 0.6 ohm primary, so a coil around 0.4-0.6 ohm s should be used.
You can use a factory canister coil that has a 1.5 ohm primary resistance, & if it has a high turns ratio will through a long spark. Looks great, eh!!!
But the spark will be low on current, & it is the heat in the current that ignites the mixture. The spark duration is also shorter.
Use 0.060" plug gaps with good spiral wound leads. GM specified 0.080" gaps for some engines.

View attachment 1716265325

The articles you post are very difficult to read. The Significant difference I was referring to was how the engine will run. He will not notice a damn thing switching between a .5 ohm coil and 1.0 ohm coil.

 

[Bewy]

George,
I have this info from a very knowledgeable electrical engineer. Checking the pri resistance of an ign coil with a digital meter will give an accurate reading. But checking the sec resistance can lead to errors & an analogue DVM should be used. He did say the reason, but it escapes me...I think it has something to do with the magnetic field that is generated whilst measuring the resistance.

 

[George Jets]

George,
I have this info from a very knowledgeable electrical engineer. Checking the pri resistance of an ign coil with a digital meter will give an accurate reading. But checking the sec resistance can lead to errors & an analogue DVM should be used. He did say the reason, but it escapes me...I think it has something to do with the magnetic field that is generated whilst measuring the resistance.

It is really interesting how these coils work.

Building a magnetic field when 12 volt power is applied to the primary winding.

Then when the signal is broken, it collapses the magnetic field inward to the many windings of the secondary. Creating an electrical charge that gets sent out to the distributor cap and on to the spark plugs to fire the fuel.

The e-coils are able to build a bigger magnetic field, in turn producing a hotter spark. It's the heat of the spark that lights the fuel.

Fascinating


☆☆☆☆☆

 

[George Jets]

On magnetic fields >

I just went round and round on coming up with a solution for a failed onboard ECU controlled voltage regulator of an '89 D100 Truck. Ended up going with a converted to 1 wire motorcraft 60 amp alternator, with the conversion of an external voltage regulator mounted on the back of the earlier motorcraft alternator. Eliminating the need of the ECU controlled voltage regulator.

The voltage regulator regulates how strong the magnetic field of the alternator is to maintain the proper 14.3 volt output. Was interesting energizing the magnetic field of the alternator and feeling the drag on it as rotating it by hand. Likewise you could put a steel wrench on the alternator pulley while energized and the wrench would stay there. Cut the power to energize and the wrench would fall off.

There is that magnetic field thing again, Fascinating...

* * * * *

 

[Ricks70Duster340]

[1] I would get a coil that has the correct primary resistance....& an E core coil. Two examples are the MSD #8207 or Summit # SUM-850500, $75 & $42 respectively from Summit.
[2] 1" spark. Sounds like that coil has a high turns ratio, which is trading voltage for current. You want a coil with high current, because it is the heat [ current ] in the spark that causes ignition.
[3] Overheating GM HEI module. The modules are internally current regulated to 5.5 amps, so they do not overheat. The only one that I am aware of that is higher is the MSD# 83647, 7.5 amps.
[4] Use 0.060" plug gaps.

Didn't GM go to the large distributor cap to provide more terminal isolation because of the larger plug gaps? With wide gaps I'd be concerned about internal cap arcing when using increased plug gaps. May not be an issue up to a certain gap though.

 

[Bewy]

Rick,
Yes GM [ & Ford ] went to larger caps. In GM's case, the bigger cap was needed to house the new E core coil. I have run HEI ign with small cap dists, no problem.
With the GM HEI cap, I have run 0.125" plug gaps. Just to see what happens.....
Nothing happened that the butt-meter could feel.