The Ford Barn

SoCalCoupe · 12-20-2021, 10:42 PM

I have a stock 1941 V8 (6 volt, positive ground.) When I bought the car 3 months ago, the generator was not charging. After a lot of learning and troubleshooting with help from koates I determined that the generator was functional so I replaced the voltage regulator, even though it looked like new. With that replacement, everything was fine, the battery was charging, for a short time, about 100 miles. Then on the way home from an event the generator stopped charging again.

The voltage regulator is a pretty simple piece of gear, electrical, not electronic. Why would it fail? Read a lot of old fordbarn posts and decided to just check all of the battery, voltage regulator, and generator contacts. Disconnected and wire-brushed every one on them. No charging after I started the engine and revved it a lot. Then, after about a minute of operation, the generator started charging again.

Don't trust the car yet. I'll keep a close eye on it. Don't want to be in the position of draining the battery, loosing generator functionality and having to be towed home.

Thoughts guys?

koates · 12-21-2021, 07:12 AM

Maybe the generator has an intermittent fault like a dirty oily commutator or worn or sticking brushes or a loose connection inside. Need to open up the gen to check it out. Regards, Kevin.

SoCalCoupe · 12-21-2021, 11:05 AM

Quote:

Originally Posted by koates

Maybe the generator has an intermittent fault like a dirty oily commutator or worn or sticking brushes or a loose connection inside. Need to open up the gen to check it out. Regards, Kevin.

If it stops charging again, that's what I'll do, open up the generator and look for problems. Intermittent faults are the worst to pin down.

Bill OH · 12-21-2021, 12:11 PM

I had the same problem. I removed and opened the generator and cleaned the field and armature connections inside, tightened brush connections and cleaned commutator with fine sandpaper. Problem solved. You might consider checking continuity between the case of the generator and ground on the regulator. I used a digital ohmmeter and found 0.1 ohm resistance. I ran a 16 ga wire with soldered connectors from the generator case thru the spark plug wire loom to a mounting screw on the regulator - that removed the 0.1 ohm resistance and stopped the ammeter from jumping.

SoCalCoupe · 12-21-2021, 02:44 PM

Quote:

Originally Posted by Bill OH

I had the same problem. I removed and opened the generator and cleaned the field and armature connections inside, tightened brush connections and cleaned commutator with fine sandpaper. Problem solved. You might consider checking continuity between the case of the generator and ground on the regulator. I used a digital ohmmeter and found 0.1 ohm resistance. I ran a 16 ga wire with soldered connectors from the generator case thru the spark plug wire loom to a mounting screw on the regulator - that removed the 0.1 ohm resistance and stopped the ammeter from jumping.

Hmmm. I already have a ground wire running from the generator to the voltage regulator case. Did check it with an analog ohm meter and got 0 ohm. Hard to see the difference between 0 and 0.1 though. Maybe it's time to buy a digital ohm meter.

The ammeter needle always vibrates. I assume that's normal? In addition to that, it's now jumpy. Might be time to open up the generator rather than waiting for it to stop charging again.

Bill OH · 12-21-2021, 08:01 PM

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Open the generator and clean the connections and commutator. Check that ground circuit between the generator and regulator with a digital ohmmeter - that got rid of the jumpy ammeter. Make sure that the terminal ends are soldered and not just crimped on the ground wire from the generator to the regulator. Strange thing is that you have to use an analog meter to check voltage on the charging system because of the interference from the ignition system, but the analog meter is not accurate to check for continuity as outlined above, thus the requirement of a digital meter. I have a Snap On meter, but there are also other quality meters.

SoCalCoupe · 01-02-2022, 09:35 PM

Quote:

Originally Posted by Bill OH

I ... cleaned commutator with fine sandpaper.

Like black 400 Grit Silicon-Carbide wet or dry sandpaper?

koates · 01-03-2022, 12:37 AM

No not wet & dry silicon carbide paper, but actual fine SANDPAPER that is used for woodworking. Regards, Kevin.

SoCalCoupe · 01-03-2022, 12:45 AM

Quote:

Originally Posted by koates

No not wet & dry silicon carbide paper, but actual fine SANDPAPER that is used for woodworking. Regards, Kevin.

Thanks!

aussie merc · 01-03-2022, 01:21 AM

defiantly would have the generator looked at sounds like the brushes are in need of attention

Crankster · 01-03-2022, 07:26 AM

Reading the various Ford and OEM service docs published over the years they are always very insistent about never using sandpaper of any kind to dress regulator point contacts, with lots of warnings and cautions. Maybe it can be made to work, but that's probably not the way to bet.

corvette8n · 01-03-2022, 10:24 AM

You can get one of these, I still have the stone my Dad used to clean my generator on my 1950 Ford back in 1964.

mfirth · 01-03-2022, 11:26 AM

Electricity is funny stuff. I had a regulator, on a marine enging, that caused a discharge. Took the cover off & it worked fine. Put cover on & discharge. Thank God I had a plastic butter tub with screws in it which I emptied & taped on the regulator to get safely home. Never figured that 1 out ....... kept it 4 a spare.

koates · 01-03-2022, 05:55 PM

Quote:

Originally Posted by Crankster

Reading the various Ford and OEM service docs published over the years they are always very insistent about never using sandpaper of any kind to dress regulator point contacts, with lots of warnings and cautions. Maybe it can be made to work, but that's probably not the way to bet.

Crankster, NEVER in any of the above posts was mention made about using sandpaper on voltage regulator contacts or any other contacts. The discussion was directed at generator armature commutators. Suggest that you reread the posts again. Regards, Kevin.

petehoovie · 01-03-2022, 07:42 PM

Quote:

Originally Posted by corvette8n

You can get one of these, I still have the stone my Dad used to clean my generator on my 1950 Ford back in 1964.

Crankster · 01-03-2022, 08:33 PM

Quote:

Originally Posted by koates

NEVER in any of the above posts was mention made about using sandpaper on voltage regulator contacts ...

I plead guilty, sorry about that. This thread is titled for regulators, and this advice is given so often ... it's just a given!

12-20-2021, 10:42 PM	#1
SoCalCoupe Senior Member Join Date: Sep 2021 Location: Point Loma, San Diego, CA Posts: 423	Voltage Regulator Comment I have a stock 1941 V8 (6 volt, positive ground.) When I bought the car 3 months ago, the generator was not charging. After a lot of learning and troubleshooting with help from koates I determined that the generator was functional so I replaced the voltage regulator, even though it looked like new. With that replacement, everything was fine, the battery was charging, for a short time, about 100 miles. Then on the way home from an event the generator stopped charging again. The voltage regulator is a pretty simple piece of gear, electrical, not electronic. Why would it fail? Read a lot of old fordbarn posts and decided to just check all of the battery, voltage regulator, and generator contacts. Disconnected and wire-brushed every one on them. No charging after I started the engine and revved it a lot. Then, after about a minute of operation, the generator started charging again. Don't trust the car yet. I'll keep a close eye on it. Don't want to be in the position of draining the battery, loosing generator functionality and having to be towed home. Thoughts guys?

12-21-2021, 07:12 AM	#2
koates Senior Member Join Date: May 2010 Location: Melbourne Australia. Posts: 2,078	Re: Voltage Regulator Comment Maybe the generator has an intermittent fault like a dirty oily commutator or worn or sticking brushes or a loose connection inside. Need to open up the gen to check it out. Regards, Kevin.

12-21-2021, 12:11 PM	#4
Bill OH Senior Member Join Date: May 2010 Posts: 425	Re: Voltage Regulator Comment I had the same problem. I removed and opened the generator and cleaned the field and armature connections inside, tightened brush connections and cleaned commutator with fine sandpaper. Problem solved. You might consider checking continuity between the case of the generator and ground on the regulator. I used a digital ohmmeter and found 0.1 ohm resistance. I ran a 16 ga wire with soldered connectors from the generator case thru the spark plug wire loom to a mounting screw on the regulator - that removed the 0.1 ohm resistance and stopped the ammeter from jumping.

12-21-2021, 08:01 PM	#6
Bill OH Senior Member Join Date: May 2010 Posts: 425	Re: Voltage Regulator Comment Sponsored Links (Register now to hide all advertisements) Open the generator and clean the connections and commutator. Check that ground circuit between the generator and regulator with a digital ohmmeter - that got rid of the jumpy ammeter. Make sure that the terminal ends are soldered and not just crimped on the ground wire from the generator to the regulator. Strange thing is that you have to use an analog meter to check voltage on the charging system because of the interference from the ignition system, but the analog meter is not accurate to check for continuity as outlined above, thus the requirement of a digital meter. I have a Snap On meter, but there are also other quality meters.

01-03-2022, 12:37 AM	#8
koates Senior Member Join Date: May 2010 Location: Melbourne Australia. Posts: 2,078	Re: Voltage Regulator Comment No not wet & dry silicon carbide paper, but actual fine SANDPAPER that is used for woodworking. Regards, Kevin.

01-03-2022, 01:21 AM	#10
aussie merc Senior Member Join Date: Sep 2016 Location: sydney australia Posts: 1,030	Re: Voltage Regulator Comment defiantly would have the generator looked at sounds like the brushes are in need of attention

01-03-2022, 07:26 AM	#11
Crankster Senior Member Join Date: Oct 2017 Posts: 563	Re: Voltage Regulator Comment Reading the various Ford and OEM service docs published over the years they are always very insistent about never using sandpaper of any kind to dress regulator point contacts, with lots of warnings and cautions. Maybe it can be made to work, but that's probably not the way to bet.

01-03-2022, 11:26 AM	#13
mfirth Senior Member Join Date: Aug 2017 Location: ohio Posts: 986	Re: Voltage Regulator Comment Electricity is funny stuff. I had a regulator, on a marine enging, that caused a discharge. Took the cover off & it worked fine. Put cover on & discharge. Thank God I had a plastic butter tub with screws in it which I emptied & taped on the regulator to get safely home. Never figured that 1 out ....... kept it 4 a spare.