Ammeter needle bounces

[Jeff/Illinois]

I'm running a rebuilt long generator from one of the major parts houses as a temporary backup on our '30 Roadster. The needle on the ammeter bounces back and forth from Pos. to Neg. in kind of a wild manner, like Dolly Parton running the Boston Marathon.

Been a while since I put this genny on the car, had some health issues last year that kinda shot the whole year for me but back in good shape now, and in the interim (been a while) and I can't recall if I put the cutout relay from my old generator onto this one, I THINK I did. Worked fine before.

Did a search for this and came up empty. I think one of my past Restorer's had an article on this but I don't have them anymore.

Help Thanks much.

[SeaSlugs]

belt tight? all electrical connections tight? Do the headlights flicker around with the needle?

[mantta]

Out of round commutator and weak brush tension.

[Jeff/Illinois]

Originally Posted by SeaSlugs

belt tight? all electrical connections tight? Do the headlights flicker around with the needle?

Good points, no they are all OK and headlites don't flicker

[Jeff/Illinois]

Originally Posted by mantta

Out of round commutator and weak brush tension.

That sounds plausible,,,, I'd say the guy that 'rebuilt' this generator probably did a clean it and and ship it job not a true rebuild. The parts house said they 'source' their starters and generators to someone else, they don't do them in house.

Weird thing, when I first got it the relay wouldn't fasten down right it was 'backwards' when you tried to put it on, if that makes any sense. I called the people I bought it from, they quickly sent the one out I have now, said they were sorry and the first generator wasn't for a Ford. It was an Autolite long generator, never saw one before set up like that.

[Tom Wesenberg]

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Not sure what the problem is without looking at it, but when I restore the ammeter I put a drop of heavy oil on each pivot point. It helps to keep the needle working right and acts as a slight damper.

[Jeff/Illinois]

Needle bouncing stopped. Don't have that issue today Now it is pegged on '0' doesn't want to charge at all. Tried different cutout same result. Didn't get the Fluke meter out this generator is a turd to begin with.

Flip the headlite switch on low beam and it drops to a negative 3 amps right off!! Ammeter seems fine.

A famous and GOOD genny rebuilder from the 'Barn is coming to the rescue, when I get his product back the one on the car will park itself on the shelf. I will probably leave it alone and let some other guy buy it at my Estate sale when I'm dead and gone.

Better Call Saul

https://youtu.be/83KLxQ1jjdg

[Terry, NJ]

Jeff, I've had this problem with more than one generator. Cause #1, is an out of round commutator. A simple chucking the armature in a lathe and turning a new surface minus the bounce tends to fix it. # 2 is the generator bolt is really tight, But just not tight enough! Funny about that. I've busted my knuckles on the fan, pulling that wrench, but it still moves.
Terry