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Discussion Starter · #1 ·
I have a Mallory ignition coil that has an ignition module and goes to a unilite distributor module.

the ignition coil is dead… in this system, can I just replace it with a regular ignition coil?
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Discussion Starter · #4 ·
I don’t know. The car came like that when I bought it and the wiring is a total disaster from the ignition switch to the coil. If I get rid of the ballast and stick a regular ignition coil on will the unilite module in the distributor still work or will I need to go back to a regular one?
 

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I'd rip all that out.
Points and Blue Streak FD471 coil, stock ford recurved distributer.
Your car will never run better
 

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The Unilite needs a 1.5 ohm coil and either the factory resistance wire in place, or a ballast resistor. Nothing wrong with using that coil. Or the Blue Streak FD471 coil, even a yellow top.
 

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The Promaster coil you have is a .6 Ohm primary resistance unit. Replacing it with a coil of the same specification should suffice. Eliminating the ballast and using an OEM 1.5 Ohm canister coil should also work just fine.
 

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Discussion Starter · #9 ·
The Promaster coil you have is a .6 Ohm primary resistance unit. Replacing it with a coil of the same specification should suffice. Eliminating the ballast and using an OEM 1.5 Ohm canister coil should also work just fine.
Thank you! That brings up another question - when the previous owner installed the mallory system it appears that they cut the pink resistance wire. For Mallory's system, in their instructions, they specify to either have the resistance wire or the ballast. Can I use the 1.5 Ohm canister without the resistance wire or the ballast?
 

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Discussion Starter · #10 ·
The Unilite needs a 1.5 ohm coil and either the factory resistance wire in place, or a ballast resistor. Nothing wrong with using that coil. Or the Blue Streak FD471 coil, even a yellow top.
The Promaster coil you have is a .6 Ohm primary resistance unit. Replacing it with a coil of the same specification should suffice. Eliminating the ballast and using an OEM 1.5 Ohm canister coil should also work just fine.
These two suggestions seem to contradict. I don't want to damage anything - can either of you clarify? Thanks so much for the help.
 

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Thank you! That brings up another question - when the previous owner installed the mallory system it appears that they cut the pink resistance wire. For Mallory's system, in their instructions, they specify to either have the resistance wire or the ballast. Can I use the 1.5 Ohm canister without the resistance wire or the ballast?
No. You need one or the other. I did not know your resistance wire was bypassed. The ballast resistor is there more to keep the Unilite module from overheating due to too much primary circuit voltage. I made the assumption they had installed it to compensate for the .6 Ohm coil.... The difference between a 3.0 Ohm (1.5 ballast plus 1.5 coil) primary and 2.1 Ohm (1.5 ballast plus .6 coil) is about 25 watts and 2 amps... maybe the Unilite module can handle it and maybe it can't. Better to err on the conservative side.
 

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Discussion Starter · #12 ·
No. You need one or the other. I did not know your resistance wire was bypassed. The ballast resistor is there more to keep the Unilite module from overheating due to too much primary circuit voltage. I made the assumption they had installed it to compensate for the .6 Ohm coil.... The difference between a 3.0 Ohm (1.5 ballast plus 1.5 coil) primary and 2.1 Ohm (1.5 ballast plus .6 coil) is about 25 watts and 2 amps... maybe the Unilite module can handle it and maybe it can't. Better to err on the conservative side.
Thank you.
 

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I'd get rid of all of that rat's nest wiring and the ballast resistor. Won't a Unilite distributor fire the coil without all of those extra boxes?
It will work without that extra box, but that little piece is a filter that protects the module from voltage spikes.....I'd agree with the others to clean up the wiring, as to that box, I never used one on my car but did on my boat......
 

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Discussion Starter · #14 ·
So my main problem to begin with is a no-crank. I was suspecting there was something in the mallory wiring that was keeping the solenoid from getting enough voltage when I turn the key to start (With the ballast it was getting 4 Volts to the I side of the solenoid). The bottom wire that went into the ballast was getting 9.6 in RUN and 8.7 in START. The resistance wire has been bypassed.

So can I crank the engine (obviously it won't run), with the ignition coil missing, and if so, how do I wire the ignition to the solenoid?

In the picture below, the red wire at the bottom of the ballast is going to the I side of the ignition switch. Can I connect it directly to the solenoid I side? Again, trying to trouble shoot a no-crank (woodchuck I think you were helping me there too).

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Discussion Starter · #15 ·
Also to clarify my understanding from reading your replies, the purpose of the ballast or resistor wire seems to be to protect the distributor unilite module, not the starter or the coil, correct? Thank you.
 

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Also to clarify my understanding from reading your replies, the purpose of the ballast or resistor wire seems to be to protect the distributor unilite module, not the starter or the coil, correct? Thank you.
Coils are either ballast resistor style or the style that doesn't require a ballast resistor. You're basically protecting the coil with a ballast resistor
in place.
Other than having heard the cliche that the "Unilite sucks"......... I can't tell you with authority that there isn't some protective benefit for the Unilite unit
by having a ballast on the car. There might possibly be.
 

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FWIW: I'm using an MSD Ready-To-Run electronic distributor with a mid-80's Ford e-coil in my 302. No ballast resistor and no Pink resistor wire- full 12 volts to everything. Plain and simple.
 

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So my main problem to begin with is a no-crank. I was suspecting there was something in the mallory wiring that was keeping the solenoid from getting enough voltage when I turn the key to start (With the ballast it was getting 4 Volts to the I side of the solenoid). The bottom wire that went into the ballast was getting 9.6 in RUN and 8.7 in START. The resistance wire has been bypassed.

The "I" terminal doesn't get a power supply. It's only purpose is, when the solenoid is energized to crank the engine, to provide the coil with full battery voltage, bypassing the ballast resistor or resistance wire. Whatever voltage you see at the "I" terminal with the key "ON" is "backfeed" from the coil+ circuit.

So can I crank the engine (obviously it won't run), with the ignition coil missing, and if so, how do I wire the ignition to the solenoid?

How you currently have it wired is the way it should be.

In the picture below, the red wire at the bottom of the ballast is going to the I side of the ignition switch. Can I connect it directly to the solenoid I side? Again, trying to trouble shoot a no-crank (woodchuck I think you were helping me there too).

No, but you should put a new "flag" terminal on the end of those wires going to the ignition switch. You can use a flattened paper clip end to release the terminal from the plug to replace the terminal.
Simple "no crank" trouble-shooting involves a couple quick checks. First, you should have a fully charged battery delivering around 12.65v at 80*F. Next, you should have near battery voltage at the "S" post of the solenoid, with the wire connected, and the key in the "START" position. If not, check the "S" terminal on the ignition switch. If you have near battery voltage THERE with the key in the "START" position then check for a bad/maladjusted Neutral Safety Switch (auto trans) or an open circuit in the RED/BLU wire going from the ignition switch "S" terminal to the solenoid "S" terminal. If everything is good and still no crank, connect a temporary jumper between the battery positive (or big common lug on the solenoid) and the "S" terminal on the solenoid. If you get no "ka-thunk" and the starter doesn't spin, replace the solenoid. If you get a "ka-thunk" and the starter doesn't spin, check for near battery voltage at the big lug on the starter-side of the solenoid with the key in the "START" position. If none, replace the solenoid. If you have voltage but no spin, remove and test the starter.
 

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I ran a Unilite with a factory coil on my '69 Cougar daily driver for over a decade. Ran great. Never had a single issue with it.

As the name suggests, the Unilite is fired by an LED and a light sensor. A full 12 volts will quickly fry the LED. (I saw it happen with other Unilites back in the 80s.) Therefore, you must run a resistance wire or a ballast resistor to protect the LED. Likely someone removed the resistance wire from the OP's Mustang before the Unilite was installed which required the external ballast resistor.

LEDs do eventually burn out. These days any Unilite is very long in the tooth which makes me wonder if the OP's LED finally gave up the ghost. I'm pretty sure you should be able to see the LED flashing if you crank the engine with the distributor cap removed and observe it in the dark or at least some good shade.
 

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Back to question one, how do you know the coil is dead? You have some wiring issues that need to be cleaned up, especially that connection at the ignition switch (yes, I am guessing that red wire is the one they used to bypass the resistor wire, what is actually holding it on?) The positive battery cable looks a bit old with the insulation pulling back, might not have the greatest connection in there. If your diagnosing electrical, I'd pull the other cable that looks like the ones they use for some thumping stereo system, just to take that out of the equation....you can bypass all of the switch wiring to the ignition with a wire with alligator clips on each end, one to the positive side of the battery and one to the side of the ballast marked 10V, crank it and see if it runs. If not then I'd move the wire on the ballast to the post marked 4V and try again. No go? Coil or module, or still some wiring somewhere. I would say the module is more likely to be bad than the coil.
 
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