The Ford Barn

DeBordEngineMan · 11-12-2022, 10:40 PM

Me again guys I have a 6 volt positive ground alternator and I'm pretty sure it isn't working. Before letting the tudor sit for 5 years I can't get the alternator to work. I always had to Rev the engine up a little bit to excite the fields to show a positive change on my amp meter I have a reproduction 6v horn and it always sounded sick and would not aooga till I reved the engine up which would be correct for a self excited alternator. I think? But it started before I parked it not showing a output on amp meter. I have tried to excite the fields with a jumper wire but no go so I thick the alternator is dead in the water. Question is should I buy a rebuild kit that you can get for a 12v alternator that changes a 12v to a 6v positive ground since I already have a alternator already set up for the 6v positive ground or just buy another brand new 6v positive ground alternator that's good go? Is there anything else that the convertion partr not make it work again? Thanks Robert

Bill G · 11-12-2022, 11:47 PM

You said you did try to excite the field, but not sure if this is the same: The single pole 6-volt alternators will loose their magnetic flux after sitting for a long period of time. Easy fix. If it is a Nu-Rex, there is a rubber plug covering two pins. With the car running, simply ground pin #1 for a second or so using some sort of jumper wire. That should restore its flux and as good as new. Probably any alternator using the S-10 knock-off alternator will do the same. Try that. Those were the instructions I got from Nu-Rex after I had mine sitting for a year being restored.

Badpuppy · 11-13-2022, 10:05 AM

Pin 1 is closer to the output post. Just place a small screwdriver blade between pin 1 and the housing (positive) for a second.

DeBordEngineMan · 11-13-2022, 10:14 AM

Thanks guys thats what I tried put a jumper wire from the first pin then to the housing for a little bit with engine running plus checked wires to make sure contacts were good but everything seemed to be OK it just didn't excite the magnetic field. After trying several times it never did show any difference on amp meter and also hooked a multmeter no difference car off or running showing 6.20 on meter. So not sure what to do. Robert

katy · 11-13-2022, 11:11 AM

You could try a good jumper from battery + to the alternator case, may or may not help, but worth a try. I've heard that those alternators need to be well grounded.

nkaminar · 11-13-2022, 05:06 PM

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Another option is to take it to a good alternator shop.

Badpuppy · 11-14-2022, 08:55 AM

Quote:

Originally Posted by nkaminar

Another option is to take it to a good alternator shop.

Those are hard to find these days. Too cheap to just swap it out (12V).

https://alternatorparts.com/6-volt-a...its-parts.html is a good source for diy or buy outright.

Try replacing the regulator first.

Dick M · 11-14-2022, 11:48 AM

I had the same problem after my A sat for a long period of time due to COVID. I took it to an auto electric shop for a checkup. They put it on a bench tester and really revved it up. He was able to excite the alternator and get it going again. He said over time it had lost its magnetic field. I put the alternator back on the car and no problems since. It is possible your regulator died but not too probable.

rotorwrench · 11-14-2022, 07:30 PM

If you don't mind doing some DIY work on it, the overhaul/conversion kits are available for the GM10si type alternators. The kit includes all that in needed for a 6-volt positive ground alternator conversion or overhaul.
https://www.ebay.com/itm/190696606664

These alternators are used on old tractors as well as antique cars so there are a lot of them around. This kit may be available from other sources for a better price. Just make sure it is for 6-volt positive ground. The kits are available in a lot of different applications and voltages.

11-12-2022, 11:47 PM	#2
Bill G Senior Member Join Date: Jun 2017 Location: Walla Walla, WA Posts: 1,047	Re: 6 volt alternator problem You said you did try to excite the field, but not sure if this is the same: The single pole 6-volt alternators will loose their magnetic flux after sitting for a long period of time. Easy fix. If it is a Nu-Rex, there is a rubber plug covering two pins. With the car running, simply ground pin #1 for a second or so using some sort of jumper wire. That should restore its flux and as good as new. Probably any alternator using the S-10 knock-off alternator will do the same. Try that. Those were the instructions I got from Nu-Rex after I had mine sitting for a year being restored.

11-13-2022, 10:05 AM	#3
Badpuppy Senior Member Join Date: Dec 2017 Location: Guthrie, OK Posts: 1,155	Re: 6 volt alternator problem Pin 1 is closer to the output post. Just place a small screwdriver blade between pin 1 and the housing (positive) for a second.

11-13-2022, 10:14 AM	#4
DeBordEngineMan Senior Member Join Date: May 2010 Location: Church Hill TN Posts: 190	Re: 6 volt alternator problem Thanks guys thats what I tried put a jumper wire from the first pin then to the housing for a little bit with engine running plus checked wires to make sure contacts were good but everything seemed to be OK it just didn't excite the magnetic field. After trying several times it never did show any difference on amp meter and also hooked a multmeter no difference car off or running showing 6.20 on meter. So not sure what to do. Robert

11-13-2022, 11:11 AM	#5
katy Senior Member Join Date: Jun 2015 Location: Red Deer, Alberta Posts: 5,096	Re: 6 volt alternator problem You could try a good jumper from battery + to the alternator case, may or may not help, but worth a try. I've heard that those alternators need to be well grounded. __________________ If you don't hear a rumor by 10 AM, start one!. Got my education out behind the barn! Last edited by katy; 11-13-2022 at 11:12 AM. Reason: Addition

11-13-2022, 05:06 PM	#6
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 4,092	Re: 6 volt alternator problem Sponsored Links (Register now to hide all advertisements) Another option is to take it to a good alternator shop. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

11-12-2022, 10:40 PM	#1
DeBordEngineMan Senior Member Join Date: May 2010 Location: Church Hill TN Posts: 190	6 volt alternator problem Me again guys I have a 6 volt positive ground alternator and I'm pretty sure it isn't working. Before letting the tudor sit for 5 years I can't get the alternator to work. I always had to Rev the engine up a little bit to excite the fields to show a positive change on my amp meter I have a reproduction 6v horn and it always sounded sick and would not aooga till I reved the engine up which would be correct for a self excited alternator. I think? But it started before I parked it not showing a output on amp meter. I have tried to excite the fields with a jumper wire but no go so I thick the alternator is dead in the water. Question is should I buy a rebuild kit that you can get for a 12v alternator that changes a 12v to a 6v positive ground since I already have a alternator already set up for the 6v positive ground or just buy another brand new 6v positive ground alternator that's good go? Is there anything else that the convertion partr not make it work again? Thanks Robert

11-14-2022, 11:48 AM	#8
Dick M Senior Member Join Date: May 2010 Location: Ukiah, CA Posts: 480	Re: 6 volt alternator problem I had the same problem after my A sat for a long period of time due to COVID. I took it to an auto electric shop for a checkup. They put it on a bench tester and really revved it up. He was able to excite the alternator and get it going again. He said over time it had lost its magnetic field. I put the alternator back on the car and no problems since. It is possible your regulator died but not too probable.

11-14-2022, 07:30 PM	#9
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,526	Re: 6 volt alternator problem If you don't mind doing some DIY work on it, the overhaul/conversion kits are available for the GM10si type alternators. The kit includes all that in needed for a 6-volt positive ground alternator conversion or overhaul. https://www.ebay.com/itm/190696606664 These alternators are used on old tractors as well as antique cars so there are a lot of them around. This kit may be available from other sources for a better price. Just make sure it is for 6-volt positive ground. The kits are available in a lot of different applications and voltages.