Squealing fan belt driving me CRAZY

[drealbmw]

Three weeks ago, my brother became the proud owner of a 1930 Model A for the first time. So everything on this old car is new to us.



It's a beautiful car, but we have a problem: fan belt squeal. In fact, the problem is so bad that he asked me for help.

The mystery began when we tried a new belt. The noise stopped, but the alternator stopped charging, too. In fact, it started discharging!

After 4 days of fiddling, we found that:

1) A new 1/2" belt stopped the noise, but the alternator no longer charged.

2) A new 5/8" belt charged the alternator, but the squealing was unbearable. If we thought the noise was bad at idle, when we turned on the lights and the a/c, the noise became 100 times worse.

We have tried everything:

1) New belts
2) New alternators
3) Soap
4) WD-40
5) Dressing
6) Circuit tracing

Now we are considering a mismatch of pulleys. Is that even a thing?

The crankshaft pulley looks like it was made for a 1/2" fan belt. The alternator pulley looks like it was made for a wider belt, such as 5/8".

We even made a clay/putty cast of the two pulleys to see if we could find a difference. We did. You can see it on this YouTube video:

https://www.youtube.com/watch?v=wlhYWdAN0Ak

We will appreciate any and all help about what to do next. We're running out of ideas.

[Anteek29]

I suspect a bad bearing in the alternator or water pump...can you turn those pulleys freely by hand with the belt disengaged?

[drealbmw]

Yes, we can turn the pulleys freely by hand when we pull the belts.

There's no drag on the pulleys and hardly any play.

[ian Simpson]

IMHO you need to replace the alternator pulley with a 1/2 inch one.

[Anteek29]

You Stated:

A new 5/8" belt charged the alternator, but the squealing was unbearable. If we thought the noise was bad at idle, when we turned on the lights and the a/c, the noise became 100 times worse.

OK...tells me the alternator is where the problem lies because the noise is in direct proportion to the electrical load. Swap it out.

[BILL WILLIAMSON]

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When I put on a leakless water pump, picked up a SQUEEL for a few days. I "think" the shaft was too long, where it hits the boss in the head???
Bill W.

[james hitchcock]

Is by any chance the belt adjusted too loose. I don't have this problem on my A, but I have a 79 pick up and it did exactly the same thing you described when the belt was loose. Took up the slack and I could hear again.

[Glenn C.]

As the pulley on the alternator is quite a bit smaller than the original style generator pulley, you need to install a cogged or notched belt, as it will conform much better to the smaller pulley. At driving speed of the Model A, that smaller Alternator pulley is turning at about 7000 RPM. Don't overtighten the fan belt as it will tear-up the water pump shaft and bushings in quick time.

How do I know ? Don't ask.

[tbirdtbird]

the correct belt width is a full 5/8. Some belts are 19/32, this will not work.
Also, get a cogged belt, it will go around the alternator pulley better.
It is squealing because your battery is low and the alternator is trying to work hard to re-charge the battery, and the belt is slipping.
Recharge the battery with a charger. Once the battery is full up the alternator will just be topping off the battery.
The soap you put on there is only gonna make things much worse, get rid of all traces of it. It will contaminate any new belt you put on there, get it off the other pulleys.
A good brand of a cogged belt is a Gatorback.
Sorry I do not have a PN
You may have to go on Amazon to get the belt you want

[goodoldvic]

Put a stock generator and EVR on it.

[drealbmw]

We have always used a cogged belt on the alternator. We're thinking about getting an old-style V belt to see if that makes any difference.

We've tried adjusting the belt every which way.
Too tight.
Too loose.
Just right.

The only way to lose the squeal is to use the 1/2" belt. But then the alternator doesn't charge.

We get 14.1 volts with the 5/8" belt.
We get 12.2 volts with the 1/2" belt.
We get 11.7 volts with the 1/2" belt and the headlights on and the a/c on.

So I wonder if this could be the problem.



There is a huge difference between the size of the "valley" for the crankcase pulley and the alternator pulley. (I just jammed plumber's putty into the pulley to get these casts.)

But I have no idea which pulley to change, or what size I would need. I don't even know how to measure a pulley. Or if this would make a difference anyway. Aren't they all the same? A pulley is just a pulley, I would think.

And I don't want to just replace parts willy-nilly. Although I probably will end up doing that.

[d.j. moordigian]

Originally Posted by drealbmw

We have always used a cogged belt on the alternator. We're thinking about getting an old-style V belt to see if that makes any difference.

We've tried adjusting the belt every which way.
Too tight.
Too loose.
Just right.

The only way to lose the squeal is to use the 1/2" belt. But then the alternator doesn't charge.

We get 14.1 volts with the 5/8" belt.
We get 12.2 volts with the 1/2" belt.
We get 11.7 volts with the 1/2" belt and the headlights on and the a/c on.

So I wonder if this could be the problem.



There is a huge difference between the size of the "valley" for the crankcase pulley and the alternator pulley. (I just jammed plumber's putty into the pulley to get these casts.)

But I have no idea which pulley to change, or what size I would need. I don't even know how to measure a pulley. Or if this would make a difference anyway. Aren't they all the same? A pulley is just a pulley, I would think.

And I don't want to just replace parts willy-nilly. Although I probably will end up doing that.

Duhhhh,....the 1/2" belt is running in the root of the pulley's,..NOT ON THE
SIDES. That's why it's not charging..

[Bob C]

To me that does not sound like a belt slipping, sound more like something
wrong with the alternator.

Bob

[CarlG]

You mentioned "A/C" ?? Didn't see the compressor in the video.

Anyway, like others have said, the noise sounds like alternator malfunction, not belt noise. Also, the cogged belt is a must. Gates BX40 (or BX42) would be my choice in this instance.

[BILL WILLIAMSON]

Originally Posted by CarlG

You mentioned "A/C" ?? Didn't see the compressor in the video.

Anyway, like others have said, the noise sounds like alternator malfunction, not belt noise. Also, the cogged belt is a must. Gates BX40 (or BX42) would be my choice in this instance.

An alternator with 1 bad DIODE, can sound like a bad BEARING, but that doesn't sound like your noise.
Bill Quiet

[C26Pinelake]

He said he already tried a new alternator. Wayne

[richsfords]

just solved the same problem, eye ball the belt from the generator side is it align with water pump and crank, I had to move the water pump shaft out just a touch to line up, it had the leakless pump with the adjustable collar with with an allen wrench. when installed it was off just a touch. take a look just for S*** and Giggles. worked for me. and all is quite on the western front.
good luck

[Tom Wesenberg]

The small 1/2" is most likely riding on the bottom of the alternator groove, so it's slipping and not spinning the alternator fast enough to make the noise. I'm wondering if you don't have a defective alternator.

Put a 4 to 6 amp battery charger on the battery for about 6 hours, then try the wide belt and see if you still get the noise.

Belts not only need to be the correct width, but the angle of the V must be correct also.

[Glenn C.]

My terminology on this may be wrong, but Tom may be on to something here. We hope you are trying to use a belt designed for the purpose i.e. Automotive belt, not a fractional type belt that would normally be used for a different purpose, such as a furnace or other mechanical type equipment.

[Bob C]

Is the crank pulley double groove as it looks like the A/C has its own belt.
Could you post a picture of the A/C side of the engine looking at the crank pulley?

Bob

[drealbmw]

The views in these photos are from the driver's side. The a/c compressor and pulleys are on the passenger side.

I'm in Austin for the next day, but will try out your suggestions when I get back to San Antonio Saturday afternoon.

Thanks for the helpful hints.

P.S. I KNOW the a/c side compressor and/or pulley are misaligned. Those are making a squish-squish sound, but I can live with that. The squealing sounds have to go!

[Jordan]

Originally Posted by CarlG

You mentioned "A/C" ?? Didn't see the compressor in the video.

Anyway, like others have said, the noise sounds like alternator malfunction, not belt noise. Also, the cogged belt is a must. Gates BX40 (or BX42) would be my choice in this instance.

It's one of Ken Davis's older units where the compressor is on the passenger side. It runs a dual belt system off of a double pulley on the crank. I'm familiar with the car. It's from Texas.

[Chuck Sea/Tac]

[QUOTE=drealbmw;1352030

P.S. I KNOW the a/c side compressor and/or pulley are misaligned. Those are making a squish-squish sound, but I can live with that. The squealing sounds have to go![/QUOTE]
So this also means you're willing to live with replacing the belt every few hundred or thousand miles?

[tbirdtbird]

Jordan, so what does he need to do about the belts? Or would it help for him to contact Ken. I did not see any pix so I assumed it was one of Ken's recent kits which is how I based my advice.
Something doesn't sound right. Did the older kit utilize the full 5/8 belt? Or less? Or did someone put on a newer alt with the requirement for the 5/8 belt? Clearly running a 1/2 inch belt in a 5/8 grooved pulley will never work; it ain't called a V-belt for nothing. The sides of the V do the gripping, not the bottom of the belt

That is why I said the 19/32 belts won't work; they bottom out in the shallow alt pulley and the sides do not make proper contact
colleyville dave

[Mike V. Florida]

...the alternator stopped charging, too. In fact, it started discharging!

I can think of no way a good alt will discharge no matter what size belt or pulley.

[Y-Blockhead]

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Originally Posted by Mike V. Florida

I can think of no way a good alt will discharge no matter what size belt or pulley.

Thanks Mike. You gave me my 1st chuckle of the day.

[drealbmw]

It looks like Ian Simpson from Alberta wins the prize!

We took his suggestion, and pulled the old 5/8" pulley from the alternator, and replaced it with a smaller, 1/2" pulley.

Then we took off the 5/8" fan belt, which was squealing but charged the battery, and replaced it with a 1/2" fan belt, which was quiet but apparently did not have enough grip to turn the alternator properly and charge the battery.

That did the trick!

We now have a smaller pulley and a smaller fan belt, but we still have enough power (14.2 volts). And NO SQUEALING!

I'm not sure why going small means larger voltage and no squealing, but I am exceptionally pleased by the results.

We can now motor around our small country town in style. And in quiet!

Thanks to all who helped us along the way.

Your suggestions will give us a head start when we tackle the next project on the a/c pulley problem.

[tbirdtbird]

OK, clarification,
his AC may not be an earlier Ken Davis Kit.
A guy from south Texas Bill Coleman sold about 15 kits that looked similar. Those kits had problems and he stopped making them