1965 barracuda charging issue

Discussion in 'Electrical and Ignition' started by 1965 Barracuda Mtl, Oct 9, 2018.

  1. 1965 Barracuda Mtl

    1965 Barracuda Mtl Member

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    Hello everyone,

    I have a 1965 barracuda with a 340. last year I had the motor rebuilt and at the same time I changed to electronic ignition and switched to the newer style charging system with electronic voltage regulator and squareback dual field alternator. At the beginning of the summer the car wouldn't charge so I did some trouble shooting and found out it was the alternator. it was still under warranty so it was rebuilt and reinstalled. worked fine for a week and then stopped working. I trouble shooted again and a diode was missing from the inside of the alternator I figured they were just crappy rebuilds so I bought a new one from another supplier. while waiting for the new one I checked the wires to eliminate a wiring issue. passed a new green wire from VR to alternator, a new blue wire from ignition source to alternator and ensured that the VR was well grounded.

    Now I installed the new alternator, verified its charge at idle (14.2V) and with higher RPM (wouldn't pass 14.6V). Assuming everything was okay I started to drive the car and after about 2 weeks the cars not charging again...

    I verified I had my 12V ignition at one of the field terminals and when I unplug the green field terminal I have my 12V there as well so my field isn't open. Bypassing the VR and bringing a straight wire from ground the the Green field terminal to test max field output there is still no charge so I can eliminate the VR being the problem right now.

    Does anyone have any idea what could keep frying my alternators?
     
  2. Willyrd

    Willyrd Well-Known Member

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    Have you had your battery tested?
     
  3. 1965 Barracuda Mtl

    1965 Barracuda Mtl Member

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    Yes the battery is brand new
     
  4. Willyrd

    Willyrd Well-Known Member

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    Have you checked your voltage regulator, there may also be some unnecessary ground like the positive wire accidentally grounding out somewhere
     
  5. 1965 Barracuda Mtl

    1965 Barracuda Mtl Member

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    I passed new wires from the ballast ignition to voltage regulator for the blue wire and a new green wire from alternator to voltage regulator so those wires are sure to be good but ill check directly on the VR and also the other wire on the ballast resistor to see if im getting a ground from somewhere else
     
  6. Tooljunkie

    Tooljunkie King of cobble/master of the broken bolt FABO Gold Member

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    Looks like another bad alternator.
    Battery voltage on one terminal, ground on other full fields the alternator. So any question of regulator or wiring is eliminated.
    So, find a good used squareback and try it. The new stuff is aparrently junk. Could be a bad diode again, or a sticking brush or broken winding in the stator or rotor.
     
  7. 1965 Barracuda Mtl

    1965 Barracuda Mtl Member

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    Ya I have a feeling its the alternator again. I'm either really unlucky or somehow my car keep shorting them. I'm just afraid to get another one and it stop working as well seeing how 3 stopped working this year each after very little use
     
  8. Tooljunkie

    Tooljunkie King of cobble/master of the broken bolt FABO Gold Member

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    K. A couple things to consider. Battery charge wire. It doesent take much torque to call it tight,any more and it could crack insulator.
    Changing pulley? It requires some care as well. I pull back half off to press a pulley on.
    Really, those alts are bulletproof and last a long time.
     
  9. 67Dart273

    67Dart273 Well-Known Member

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    It...........just...........sounds.........like.........bad luck of the draw on alternators, you might check

    Above, the charge wire. The way I'd do this is get it working, and with the engine warm, battery normalized, check both with accessories off, and with heater, lights, whatever turned on

    With engine running to simulate "medium cruise" RPM let's say 1500-2000RPM or so, check battery voltage should be normal at about 14V nominal

    Now check the charge wire, if there is more than 1 volt difference, start looking

    If the voltage is "way" up there let's say 17-18V then I'd really get busy.

    Then take a good look at the brushes/ area/ slip rings for oil. Maybe you have a valve cover etc oiling the thing down some, etc.
     
  10. BillGrissom

    BillGrissom Well-Known Member

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    Your finding diodes missing in a square-back alternator is like my experience in my 1982 Dodge Aries 2.2L. Apparently that was their first application of the square-back in a FWD car. My suspicion is that didn't allow enough air flow to cool the diodes. I would find the 3 positive-side diodes that "hang in the air" gone, almost every year like clockwork. The 3 negative-side ones on a buss-bar that bolts to the case were always fine (better cooling?). That car required unbolting the AC bracket to remove the alternator, which was a pain. Instead, I started splitting the alternator case in half underneath to take it out in 2 pieces. I also started buying just the diodes at an auto electric shop. The guy there said they saw that failure all the time. I started cutting cooling slots in that diode bracket on a bandsaw, which seemed to give 2 years between melt-downs. Eventually that engine had a head gasket failure (endemic) and enough other problems (crazed paint, ...) that I scrapped the car. Not Chrysler's finest decade, and perhaps why you see more Darts than Aries on the road today. In contrast, the round-back alternator diodes are pressed into the case so rarely fail, though my 1965 Newport apparently failed one (rebuilt alternator), and running on 2/3 was just enough to trick me into getting stranded (infamous click-click-click no-crank).
     
  11. 67Dart273

    67Dart273 Well-Known Member

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    I actually ran my 69 RR for a short time with two diodes cut out, they had shorted. It was between paydays LOL. The "infamous" failure was a loaner car I had about a 69 Valiant. Went out one morning to start it and warm it up. When I got back out, the loose belt was smoking. I did not realize a diode had fallen out of the mount and inside the alternator. When I wiggled the pulley with a rag, the diode wire shorted and burned up the underhood harness, THEN popped the link. Called the dealer and told them "send a wrecker and a different loaner." They sent the wetback with booster cables. HE looked at it and said "you are gonna need a tow truck!!!."
     
  12. 1965 Barracuda Mtl

    1965 Barracuda Mtl Member

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    I have an aftermarket VR so I ordered an original mopar one and waiting for the new alternator to run some tests. someone told me to look at the alternator gauge for some sort of a feedback. I haven't really troubleshooted past the fire wall or behind the dash. do you think it would be worth it to give it a look?
     
  13. 67Dart273

    67Dart273 Well-Known Member

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    "It might be" that poor ----REALLY POOR---- connections in the charge path, including the ammeter, the bulkhead connector......are suddenly causing "spikes" in the charge current and are "killing" diodes

    One easy way to troubleshoot this would be to temporarily "rig" a small test wire from the output stud on your alternator. One way would be to connect it to a voltmeter if you have one for a spare for a week or so. Another would be to use a 12V indicator lamp of some sort, even a dash lamp. You would need to rig it so you can disconnect when not driving, so a switch. You would need to find a way to run it into the pass compartment

    So, example: Connect to alternator output stud, a small fuse holder say, 2A fuse, use small 18 or 16 ga wire. Run into pass conpartment, connect a small 12V test lamp/ indicator lamp. From the lamp run back out into engine bay and connect straight to battery through a second small fuse. Starter relay "big post" is a good place

    If the lamp glows dim right after starting, this is OK. Shows a small amount of voltage drop in the charging path to the battery. What is BAD, which would show poor connections along the way, is a fairly bright lamp, or the lamp "blinks" bright/ dim at odd times, showing a connection making/ breaking

    If the lamp burns out YOU KNOW there is a bad connection LOL