1963 Valiant. Slant 170 w/ turbocharger, MSD6 BTM, 400W stereo system. Bought it that way and power never seemed to be an issue. No idea what alternator was in there but it was a round back with only one field wire running from an old style voltage regulator (black box). Maybe that means it was a 30A model? There is a switched 12V line run down there but its taped up and not used. ANyway, it ran great that way until the alternator died. The autozone replacement is a 60A squareback with 2 field connections. I read about upgrading the regulator so I put in a C8313. I hooked it up like the old one (one field wire, ignore the other terminal, it doesn't charge. Figured I got a bum alternator so I took it back and got another of the same with same result. Did some reading and it looks like I need to apply switched 12V to the other field terminal as so many diagrams say to, but then I get smoking wires when I hit the ignition! I tested the C8313 and I get the right resistance (1.75k ohms) but when I tried testing it by applying 20V from a drill battery to the blue terminal and watching for the green side to go to ground, it only seems to work if I reverse the terminals (power to green, blue goes to ground). But if I swap the blue/green wires in the car, I still get smoke so I'm not sure if that even matters. Due to all the smoked wires, I ended up pulling the dual ballast out cuz it got super hot too and just connecting al the power wires together. Maybe that was a bad idea but I had trouble figuring out why I needed the ballast. With the ignition off I measure less than an ohm resistance to ground from either field terminal so that makes sense that I'm basically putting 12V to ground and getting smoke. Does that mean this alternator is bad out of the box or is ti supposed to be that way? If so how does it makes sense to apply a voltage?? I feel like I'm following red herrings all over the place and missing some basic detail.
Alternator swap driving me nuts!
- Thread starter m jocko
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If the vendor sold you a square back proper for your application, one terminal is a brush holder and gets the green wire from regulator. A second small terminal would be chassis ground for the field. Upgrading to isolated field and later regulator is pretty simple but you would need alternator built to isolated field spec, i.e. both are brush holders.
Thanks for jumping in RedFish. So if the field terminals measure no resistance to ground, that means I should only be connecting the one green field wire, right? But it won't charge. Shoudl I go back to the old style regulator? I bench tested it and it works as expected. I tried unplugging the field wire and jumping the terminal to ground to force the alternator to charge and I get nothing. I'm basing this off measuring voltage at the battery and the alternator post. They both give about 12V with no change when I ground the field terminal. I see bunches of videos saying this the way to test the alternator in the car but is that wrong for the older 1 field wire configuration?
With no wires connected, I don't believe both should be common to chassis ground. I don't remember all I knew. @67Dart273
340six
King Of Bling
One of the fields is grounded, and they forgot to clip the terminal off. They sometimes forget, so you would not put a field to a ground.
Look and see what one of the fields is grounded.
Look and see what one of the fields is grounded.
OK, so back to original configuration. Car runs great, but I still get no more than 12.4V at the battery (off/on/running all the same). When I measure at the alt output post I'm getting 13V now, but still nowhere near the 14V I expect. I'm going to try to go back to the original regulator next I think but I feel like I've been there already...
@340six I can't figure which terminal is grounded because they both measure as grounded (power off).
@340six I can't figure which terminal is grounded because they both measure as grounded (power off).
With the square back alternator, you MUST ground one of the field terminals on the alternator for it to charge. It does not matter which one. Attach the wire from the regulator to one of the field wires and ground the other. Mine has been that way three years now. I still have the old style voltage regulator and it works fine. Easy peasy.
Thanks everyone, I was starting to wonder if its all working but this alternator just sucks and is only giving my 13V. I randomly tried swapping polarity on the regulator and got 18+V for a sec and shut it all off ASAP! So I guess it *can* put out more, it just doesn't want to. Anyways, it started raining and I'm working outside so I'll let you all know how this turns out tomorrow.
Try running the engine at fast idle and measure voltage both at the battery and at the alternator stud. Maybe you have an open/ bad connection in the ammeter/ charge circuit
If the two voltage readings are no more than say, 2-3V apart, and should be less, then you can test the full output of your new unit by disconnecting the green, and jumpering the alternator field terminal to full 12V You can jumper right to the alternator output stud. Be careful, it is always hot to the batter. Watch the RPM, and battery voltage, and if it charges, don't let RPM cause it to climb over say, 16V With headlights, heater, you should be able to bury the ammeter.
If it has two field terminals, and can both be INSULATED, consider converting to the 70/ later VR. All you need is the matching pigtail and connector, and add one more wire.
If the two voltage readings are no more than say, 2-3V apart, and should be less, then you can test the full output of your new unit by disconnecting the green, and jumpering the alternator field terminal to full 12V You can jumper right to the alternator output stud. Be careful, it is always hot to the batter. Watch the RPM, and battery voltage, and if it charges, don't let RPM cause it to climb over say, 16V With headlights, heater, you should be able to bury the ammeter.
If it has two field terminals, and can both be INSULATED, consider converting to the 70/ later VR. All you need is the matching pigtail and connector, and add one more wire.
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Hold on, the C8313 is intended for a dual field alternator wiring setup. What regulator are you using now?
Re read the thread. We talked about that. He can ground on field terminal if he has the old regulator
Alright, I'm back at it. I been trying to use the C8313 regulator with the single field connection alternator so I guess it shouldn't work. Although it really seems like its charging because I'm driving the car around and not loosing battery voltage. But the only way I can get the system to measure more than 12.4V is if I hotwire 12V directly to the field terminal. Then I get 14+V and it pulls the idle down as expected, giving me confidence that the alternator is good at least (thanks @67Dart273 - I looked for this everywhere and all I found was how to test a 2 field connection alternator by grounding it). So I tried bench testing the new regulator, the old regulator and neither one of them works like I expect. Maybe someone can tell me if I'm understanding the functions correctly.
The old one (C8010) passes 12V through to the field terminal but when I apply more (20V drill batt) that goes right through the the field terminal as well. I believe this style should allow 12 V through but shut off if the input is over ~14V. This would explain why this regulator results in 18+V at the battery when I try to use it.
The new one (C8313) used to measure 1.75kOhms as I read it should and I could adjust that with the pot on the back. But now it measures near 0 and the pot does nothing. Applying the 12 and 20 voltages, I can't get the output to switch to ground when I could before. So I must have burnt it somehow messing around with all this. Oh well, it was the wrong kind of regulator for my alternator anyway right?
I just ordered a new C8010 off ebay which should arrive next week. The weird part is the car still seems like its charging, at least partially, because I'm driving it around and the battery's not dying.
The old one (C8010) passes 12V through to the field terminal but when I apply more (20V drill batt) that goes right through the the field terminal as well. I believe this style should allow 12 V through but shut off if the input is over ~14V. This would explain why this regulator results in 18+V at the battery when I try to use it.
The new one (C8313) used to measure 1.75kOhms as I read it should and I could adjust that with the pot on the back. But now it measures near 0 and the pot does nothing. Applying the 12 and 20 voltages, I can't get the output to switch to ground when I could before. So I must have burnt it somehow messing around with all this. Oh well, it was the wrong kind of regulator for my alternator anyway right?
I just ordered a new C8010 off ebay which should arrive next week. The weird part is the car still seems like its charging, at least partially, because I'm driving it around and the battery's not dying.
These are not hard. Don't over think it, and you cannot test regulators with an ohmeter. All the tests you need to do can be done right on the car, unless you identify that EG the alternator is not charging, and decide to tear it down for detailed diagnosis.
The flat electronic has ground and two wires. One goes to switched 12V, and that same switched 12V branches off and feeds either field of the alternator. The F terminal, green, of the regulator feeds the remaining field. The regulator MUST be grounded. That regulator, in a manner of speaking, controls "the amount of ground" on the remaining field. To full field it for testing, unhook the green at the alternator and ground that alternator terminal. This leaves the blue switched 12V wire feeding full power through the field, to ground
The single field connection, the alternator field MUST be grounded on the other end. Use an ohmeter to make darn sure. The rebuilders screw these up. Double check by installing the alternator, and BEFORE you hook up the regulator, jumper 12V into the insulated field connection. Start, run the car, and monitor battery voltage. Slowly bring up RPM and the voltage should climb. DO NOT allow it to go past 16V
The old style regulator simply monitors battery voltage, and controls the amount of power feeding TO the field, with the other end of the field grounded.
Below 13-13.5 or so IT IS NOT charging, plain and simple. Once you get the battery charged and normalized, with the thing running anywhere above idle, and with minimum loads AKA heater/ lights off, the battery should run nominally 14V.
Simple
The flat electronic has ground and two wires. One goes to switched 12V, and that same switched 12V branches off and feeds either field of the alternator. The F terminal, green, of the regulator feeds the remaining field. The regulator MUST be grounded. That regulator, in a manner of speaking, controls "the amount of ground" on the remaining field. To full field it for testing, unhook the green at the alternator and ground that alternator terminal. This leaves the blue switched 12V wire feeding full power through the field, to ground
The single field connection, the alternator field MUST be grounded on the other end. Use an ohmeter to make darn sure. The rebuilders screw these up. Double check by installing the alternator, and BEFORE you hook up the regulator, jumper 12V into the insulated field connection. Start, run the car, and monitor battery voltage. Slowly bring up RPM and the voltage should climb. DO NOT allow it to go past 16V
The old style regulator simply monitors battery voltage, and controls the amount of power feeding TO the field, with the other end of the field grounded.
Below 13-13.5 or so IT IS NOT charging, plain and simple. Once you get the battery charged and normalized, with the thing running anywhere above idle, and with minimum loads AKA heater/ lights off, the battery should run nominally 14V.
Simple
The 70/ later regulator is FAR superior and easier to get, at least easier to get one that actually works. All you need is one more wire to convert to the electronic regulator. You have most of the battle won with the isolated field alternator. THEY ARE NOT correctly called "single" or "dual" field. "Isolated field" is the 70/ later type, whether round or squareback.
Simplified 70/ later The wire at top named "ignition" branches into the ignition "run" circuit, usually dark blue. It branches off and connects to one of the two fields. Notice which one on the regulator.
The remaining regulator terminal, green in OEM, goes to the remaining field. Does not matter which you can switch them. The alternator is grounded by the mount, the regulator MUST have a good ground via the mounting screws. Scrape them clean, and the firewall, and use star lock washers
The remaining regulator terminal, green in OEM, goes to the remaining field. Does not matter which you can switch them. The alternator is grounded by the mount, the regulator MUST have a good ground via the mounting screws. Scrape them clean, and the firewall, and use star lock washers
Pre 70. The regulator is fed switched ignition "run" power at the top, and the field terminal goes to the insulated/ isolated field on the alternator. The remaining field must be grounded, and so must the regulator.
If you can full field the alternator, and with the battery charged, say, overnight on a proper charger, then run the engine, turn on all loads, lights, heater, etc, and monitor batt voltage. If you can bring up RPM and exceed 14V you are done with the alternator. It works
Decide which regulator to use. If you are using the early one, make CERTAIN one field is not grounded, and ground the other one and connect it up.
If you are going to use the 70/ later VR, then UN ground and make CERTAIN the fields are ungrounded, with a meter. Then connect it up and you are done. You have tested the alternator. If it does not work and the VR is grounded, and you double checked your wiring, you have a defective VR
You can buy the pigtails
Standard Motor Products S-573 Standard Motor Wiring Connectors | Summit Racing
If you are using a junkyard one, insure and suspect that it is corroded and may not be making contact.
Decide which regulator to use. If you are using the early one, make CERTAIN one field is not grounded, and ground the other one and connect it up.
If you are going to use the 70/ later VR, then UN ground and make CERTAIN the fields are ungrounded, with a meter. Then connect it up and you are done. You have tested the alternator. If it does not work and the VR is grounded, and you double checked your wiring, you have a defective VR
You can buy the pigtails
Standard Motor Products S-573 Standard Motor Wiring Connectors | Summit Racing
If you are using a junkyard one, insure and suspect that it is corroded and may not be making contact.
This is my system ^^^^^^^ and it works FINE.
I am using the old style regulator with an alternator off of a dakota. I just grounded one field.
That's all that needs to be grounded. The other goes to the regulator.
OK, new pre 70 VR adn it all works perfectly. My alternator had 2 field terminals and looked like a newer isolated field so I wrongly assumed it was. After convincing myself I had a grounded terminal, it makes sense because the application chart for this alternator shows my 63 valiant. Anyways, thank you for all the help!
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Yeah, a lot of rebuilders have been taking isolated-field alternators and internally grounding one end.
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