HEI Conversion Coil Question

[1973dodger]

I've done a recent 4 pin HEI module conversion to my 1973 Charger/440 and have eliminated Chrysler electronic ignition and ballast resistors. The question I have is, which circuit coming out of the bulkhead should be used to power terminal B of the HEI module, which also goes to + side of the coil? There is a START wire and a RUN wire coming out of the bulkhead, I would assume the "start" wire goes to the ignition relay/solenoid going to the starter and the "run" wire to the + side of the coil. Problem is, while cranking "run" wire doesn't have power until ignition switch is in run position, therefore no power to the coil while cranking. So question is, what circuit is hot while ignition key is in cranking position and in run position?

 

[bobsgtx]

From what I have read in the past is you hook the ign. 1 and 2 together so you have power while in crank and run position.

 

[Carcinogen]

I put a push button under the steering column for the starter. Turn key on, push button for starter, also acts as anti-theft deterrent as button is hidden. Start on key is hooked to latching solenoid that cuts battery power to help prevent theft.

Also make sure of full voltage to coil, old wire and corroded connectors needed to be replaced on my 72. Also make sure coil is compatible with HEI ignition, I’m using E-coil for late model Camaro.

 

[1973dodger]

I was just curious about back feeding current if using both feeds to the coil? Any thoughts? Gues I could use some diodes to make sure the current only feeds on direction.

 

[RJRENTON]

I was just curious about back feeding current if using both feeds to the coil? Any thoughts? Gues I could use some diodes to make sure the current only feeds on direction.

WHY would you use diodes??....and what values were you considering? Not the 1N4001....not enough amp capacity....there is NO BACK FEEDING, as the "start wire...the brown wire" is only connected in the ignition switch when in the start or crank position.....diodes are not needed.......just my opinion of course......
BOB RENTON

 

[Bee1971]

Wouldn’t it bee easier to gut the coil side of the dual ballast resistor , install your jumper wire between the two terminals for the coil side , solder new wire in place - Re-install factory wiring connectors back to dual ballast resistor - Full power to + side of coil in start and run with a factory look

 

[1973dodger]

Ballast resistor has been removed to unclutter the firewall, my thought is why have it on the firewall if it's not going to be used? As far as some thoughts on the diode, the link below is similar to what I thought of using. 5 PCS 20A10 | 1000V 1KV Axial Bridge Rectifier Diode | General Purpose | US Ship | eBay

 

[RJRENTON]

Ballast resistor has been removed to unclutter the firewall, my thought is why have it on the firewall if it's not going to be used? As far as some thoughts on the diode, the link below is similar to what I thought of using. 5 PCS 20A10 | 1000V 1KV Axial Bridge Rectifier Diode | General Purpose | US Ship | eBay

And HOW would you connect the five (5) diodes? In series, or a series/parallel arrangement or a full wave bridge (only 4 diodes are needed) or a voltage doubler or tripler arrangement or ???? Are you taking into account the forward voltage drop through the diode arrangement .....each diode has a forward voltage drop at rating....show us your circuit arrangement.......curious minds want to know....
BOB RENTON

 

[Canadian1968]

The swap is dead simple , as explained . The easiest way , was just to jump the two wire for the ballast. Either stealth by hiding the jumper wire in a gutted ballast or remove the ballast and just add the jumper wire , make it as fancy or crude as you want.

You said you " removed the ballast " what did you do with all the wires? Those are all you need .

 

[1973dodger]

And HOW would you connect the five (5) diodes? In series, or a series/parallel arrangement or a full wave bridge (only 4 diodes are needed) or a voltage doubler or tripler arrangement or ???? Are you taking into account the forward voltage drop through the diode arrangement .....each diode has a forward voltage drop at rating....show us your circuit arrangement.......curious minds want to know....
BOB RENTON

You obviously are more knowledgeable concerning these matters than I, hence my asking for advice. I picked these particular diodes for the current rating, just happens to be 5 in a package. How would you arrange them, or am I barking up the wrong tree?

 

[RJRENTON]

You obviously are more knowledgeable concerning these matters than I, hence my asking for advice. I picked these particular diodes for the current rating, just happens to be 5 in a package. How would you arrange them, or am I barking up the wrong tree?

See my #5 response......you do not need diodes. Read subsequent messages.....just jump the ballast resistor as noted....the module will get 12volts for starting AND RUNNING.....
BOB RENTON

 

[1973dodger]

See my #5 response......you do not need diodes. Read subsequent messages.....just jump the ballast resistor as noted....the module will get 12volts for starting AND RUNNING.....
BOB RENTON

Yeah I saw your response previously posted, basically my response is simply this; Why keep the ballast resister in the loop whenever it's function is being bypassed other than the appearance of a stock look? Why not simply take the 2 feeds (start/brown & run/blue wires from the bulkhead) directly to the coil + and eliminate the ballast resister altogether? The less connections, the less potential problems in the future. So back to my original question, is there a potential issue with back feeding in either direction? There is a reason for me asking this particular question, as described above, this is how I currently have the coil wired and I have noticed when shutting the key off after running, the engine continues to run for a couple of seconds before shutting down.

 

[Gold Rush]

Here is how I have my GM HEI wired into my "74 SE. Never experienced the run on you speak of. Hope that helps

 

[Geoff 2]

As Bob Renton said, you do NOT need diodes, nor would you use them with this type of ign system [ inductive ign ]. More voltage, more spark energy. Diodes have an internal voltage drop of approx 0.5 volt, so that is 0.5v less getting to the coil.

Post #2 describes the simple procedure for wiring up the HEI. The HEI coil does draw more current than the Chrys coil. That means there will be more voltage drop in the wiring to the coil, hence the coil gets less voltage.
The optimum system is a 4 pin relay. The existing wires trigger the relay. The relay then supplies the module & coil direct from the bat + terminal or large alt terminal. Install a 10 amp inline fuse. This ensures you will get the best out of the HEI system.

 

[1973dodger]

As Bob Renton said, you do NOT need diodes, nor would you use them with this type of ign system [ inductive ign ]. More voltage, more spark energy. Diodes have an internal voltage drop of approx 0.5 volt, so that is 0.5v less getting to the coil.

Post #2 describes the simple procedure for wiring up the HEI. The HEI coil does draw more current than the Chrys coil. That means there will be more voltage drop in the wiring to the coil, hence the coil gets less voltage.
The optimum system is a 4 pin relay. The existing wires trigger the relay. The relay then supplies the module & coil direct from the bat + terminal or large alt terminal. Install a 10 amp inline fuse. This ensures you will get the best out of the HEI system.

Would you by chance have a diagram of the 4 pin relay wiring or perhaps post a link. From what you have described may be the missing link I'm seeking.

 

[RJ Squirrel]

I agree with Bob and others, there is nothing wrong with simply wiring the start and run wires together, and connecting a single wire from there to the + side of the coil and then on to the module. The start lug inside the ignition switch will be energized while running, which is not a problem because it does not contact anything while key is in run position. I have mine wired this way. If you discover that you have a voltage drop, then the relay Geoff suggests is the fix. I also have an adjustable electronic voltage regulator on mine that maintains the system charge voltage at 14.2.
and lastly, use a coil compatible with the module such as an e-core or a pertronix 3, if you dont it will ruin the module. I know this from experience.

 

[RJRENTON]

I agree with Bob and others, there is nothing wrong with simply wiring the start and run wires together, and connecting a single wire from there to the + side of the coil and then on to the module. The start lug inside the ignition switch will be energized while running, which is not a problem because it does not contact anything while key is in run position. I have mine wired this way. If you discover that you have a voltage drop, then the relay Geoff suggests is the fix. I also have an adjustable electronic voltage regulator on mine that maintains the system charge voltage at 14.2.
and lastly, use a coil compatible with the module such as an e-core or a pertronix 3, if you dont it will ruin the module. I know this from experience.

There is nothing "magical" about an "E" core coil (physical appearance)..it's a core form design (vs a shell form design) and the lamination type (lower core loss) and epoxy insulated, but it's the primary impedance and volts/turn ratio allows it to produce a higher secondary voltage. The HEI module permits 12 volt primary coil switching without a ballast resistor to limit voltage & current to the coil as the Mopar ECU requires.....just my opinion of course.....
BOB RENTON

 

[RJ Squirrel]

Thanks Bob, appreciate your input. Do you have an opinion on what the best coil for HEI would be? I did a lot of searching for that answer and never came up with anything definitive other than to use the E-core. I believe Ray/Halifax recommends the Pertronix 3, it has a low primary resistance similar to the E core at .32, but I have had no experience with it. I was hesitant to use another cannister coil after I ruined my first module doing that.

 

[RJRENTON]

Thanks Bob, appreciate your input. Do you have an opinion on what the best coil for HEI would be? I did a lot of searching for that answer and never came up with anything definitive other than to use the E-core. I believe Ray/Halifax recommends the Pertronix 3, it has a low primary resistance similar to the E core at .32, but I have had no experience with it. I was hesitant to use another cannister coil after I ruined my first module doing that.

Go with what Ray/ @HALLIFAXHOPS recommends...it resembles an OEM design yet is compatible with the HEI module and purchase a E Coil and compare. Bear in mind, that there is NO 50+ hp increase in either system in spite of what your buddies may think....BOB RENTON

 

[1973dodger]

Same subject, but different. How do you know if the HEI module is defective or damaged? 1- Either creates spark or it doesn't or 2- Develops a miss 3- Something else