Noisy generator bearing?

[Hotrodvideo]

I had the generator in my 81A flathead rebuilt & converted to 12 volts a few months ago, Now that the car is running, it's pretty noisy, like a squeaky sound when it's turning. I know it's the front bearing, I've oiled the rear a few times using the oil cap so that one should be alright.

My question is, are they supposed to make a noise or be completely silent?

[Brendan]

i would think you would hear some brush noise, the brushes rubbing on the comutater...

[don's 37]

The bearing is suppose to be silent but like Brendan said, the brushes will make a little sound of their own. Sounds like you might have a bad bearing.

[PeteVS]

Grab a broom. Press the end of the handle on various areas of the generator while the engine is running and then press your ear against the side of the broom handle. Kinda like a stethoscope. That might localize the noise source and hence, the guilty part.

[Cecil/WV]

I had that sound on mine and thought it was the front bearing, but it turned out to be the belt squeaking. If you spin it by hand with the belt off, you should hear a bearing noise. Try spraying belt dressing on the belt with the engine running.

[G.M.]

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Could also be brushes or belt as Cecil said. Squirt a little WD-40 on one of the water pump pulley's and see if the noise go's away. I use a 12" piece of heater hose to listen. G.M.

[Hotrodvideo]

It's not the belt or the water pumps. It must be the front bearing, you can hear it loudly when you turn the fan pulley on the generator with the belt off.

Do the early generators with fans attached usually wear out the bearings quickly because of the extra weight? That's my guess.

[don's 37]

It's possible. I think it's a poor design if you ask me.

[B-O-B]

Could you have over tightened the belt. Belt should have 1/2" to 3/4" deflection when pressing on it with ENGINE OFF. That will cause the bearings to wear out quicker. I would check with the rebuilder to see if he replaced the bearing.

[Bruce Lancaster]

Front bearing is easy to get to, it may be shot or maybe the rebuilder put in one of those nice sealed bearings that don't have enough grease...
The bearings are very durable if adequately packed, excess wear is mostly caused IMHO by excessively tight belt.
The broom handle will work fine, but watch out for that fan!
You don't want to be in tomorrow's paper:
"Local man found dead with broom shoved through skull. Police baffled, next-door neighbor says he was very depressed over a failing generator..."

[Hotrodvideo]

On a stock '32, I'm stuck using a gen/fan setup, there's no room for an extra crankshaft pulley to run a fan off of the crank because the stock crossmember is in the way unless I cut down the front crossmember which I really hate to do!

[peteyshoes]

i,m surprised there isn't an oil wick for this? original wasn't sealed. IF your positive the noise is not the brushes, then the bearing is to blame. b-o-b is right in asking if bearing was replaced, and over tightening of belt. see if you can't get the right bearing in there. (if there's no oil cup or wick/hole, see if shop will drill one---or get another front plate.)

[Hotrodvideo]

There is no oil cup in the front, only in the back. But is there a wick for oil somewhere else in the front that I might have missed??

I know I did not over tighten the belt, it has about 3/4" deflection in it.

[rotorwrench]

One more thing that hasn't been mentioned would be if the rotor is rubbing the field winding in there. They are usually a pretty close fit especially on a converted generator. The brushes are generally pretty silent on an alternator since they don't have segments like a generator armature does. The alternator front rotor bearings usually have a removable seal and can be serviced if you are game to try it. An alternator should never make more than a normal whirring sound when brought up to speed unless it is pulling a heavy load to charge a low battery or something to that effect. If a diode plate goes out, they will whine and not charge well if at all.

Kerby

Woops, my bad, not alt still gen

[Chris Nelson]

I have had belts make a noise that sounds like a bearing going out. If there is a ball bearing in the front, you could replace it easily. I don't know if they used oilite bushings like some rear bearings in generators. Sealed ball bearings are the best for high speed. When they make them, they put just enough grease in the bearing, which some may think is not enough. Too much grease causes heat and premature failure. In bearing school I learned that if a ball bearing is stood up on its side, the amount of grease necessary would come up only midway on the bottom ball. More than that will cause heat. Ball bearings are meant for high speed, unlike roller type bearings which are meant for slower speed and heavier loads.

[B-O-B]

Rotorwrench he said it is a converted generator to 12V not alternater. If I converted one I would surely use an alternater tho.

[Hotrodvideo]

according to the ammeter, it is charging. I'm not sure exactly what bearing they put in it. I'll have to take it back to them and show them how noisy it is.

[David J]

Left is 32 , center is 33 & right is 34- . The oil cup is there on all 3 . The gennie bearings were tapered roller as you can see . The ring above the 33 is to keep the die cast retainer from moving as that is what sets the preload on the front bearing . Maybe they aren't using stock stuff like this but if they are the front bearing not being tightened properly can make noise . Mebbe dis izzn't it but it's worth a look . David J

Originally Posted by Hotrodvideo

There is no oil cup in the front, only in the back. But is there a wick for oil somewhere else in the front that I might have missed??

I know I did not over tighten the belt, it has about 3/4" deflection in it.

[Hotrodvideo]

The engine is a '38 81A and I think he used a '39 generator to convert it to 12V??
How hard is it to take the generator apart to take a look?

[David J]

Just looked at the generator on the 39 motor I yanked out of the 33 4d and it doesn't have an oil cup . Not familiar with that type other than the shaft is bigger & the pulleys don't interchange . The info I posted above probably doesn't apply to what you are using . Sorry & good luck .

Originally Posted by Hotrodvideo

The engine is a '38 81A and I think he used a '39 generator to convert it to 12V??
How hard is it to take the generator apart to take a look?