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318 w/ electronic ignition


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I have a 41 biz coupe that has had a 318 installed with electronic ignition upgrade. When I got it, she didn't run, and after a few months tinkering was able to get it to fire up. 

I then find out the alternator wasn't charging so I replaced it, but when I installed it, I didn't have the correct field wire clip so I connected the wire to the bolt holding the clip, which I now think may have been insulated since as I tried to start it, I heard a pop under the dash, and my power cable between the fusible plug was fried. I fixed the wire but then the connection on my column between power, ign1 and ign2 became very hot, and as I shut it off the fusible link wire I fixed was glowing it was so hot. 

So it's been over a week now changing burnt wires, checking continuity between connections looking for the short I must have in my system.. guess my question is am I on the right track? I'm assuming because the connection on the column is getting hot my short must be near there? Or is it just because that's where the switch is?

My current situation is I replaced the fusible link with an inline fuse, running a 20Amp fuse, and as soon as I turn the key it blows the fuse...

Any help is good help at this point. 

Edited by 41businesscoupe (see edit history)
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If the alternator has only one insulated brush, you need to run a mechanical regulator with it. Both brushes have to float for the electronic regulator. Chrysler says not to run the mechanical regulator on a car with electronic ignition, but I did it for years with an orange box ignition, and no issues. Still, it sounds like you have stuff that wont work together, so you might as well do it Chrysler's way and run an electronic regulator.


Don't connect to any screws. The screws go into the alternator case aluminum, and are grounded whether the associated brush is or not. That may well be the problem. If there are 2 brush wires, one of them goes straight to the key.


All of the old roundback alternators have a grounded brush and can only be used with a mechanical regulator EXCEPT the 1970 roundback alternator, which has both brushes insulated. The squarebacks (1971 up) have both brushes insulated.


Wiring for the old mechanical regulator is real simple.

power from key >> regulator power terminal.

regulator field terminal >> insulated brush on alternator.


Wiring for the electronic regulator goes like this:

Power from key >> regulator power terminal (center terminal) AND ALSO to one alternator brush.

Regulator field terminal (outer terminal) >> other alternator brush.

It does not matter which brush is which.


The difference is the old mechanical system sends 12v to the field to make it charge, but the electronic regulator grounds the field to charge. That is why the mechanical system can have a brush grounded and an electronic one absolutely cannot.


Both types of regulator must have the regulator case grounded. They are usually bolted to steel, but if they weren't, there would need to be a ground wire to the regulator case.


It is possible to use a squareback alternator, or a 1970 roundback with the old mechanical regulator, you just have to ground one brush. You can't go the other way because there is no way to un-ground a brush on a 1969 or earlier roundback.


Mechanical regulators have two fuse wires inside. They can usually be repaired, though most people don't know. On the electronic ones, toast is toast.


Electronic regulator looks like this:




Mechanical one looks like this:




A roundback alternator looks like this, note one brush is grounded:




A squareback looks like this, note both brushes are insulated and have spade terminals:



Edited by Bloo (see edit history)
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I don't recall the source, but someone makes an electronic regulator that will replace the mechanical type.


My '65 Chrysler has a round back alt with the single field terminal and a regulator that looks like the mechanical type, but has electronic guts inside.

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