[455rebel]

It started about a month ago, noticed a squeal, looked under hood,
belt had flipped, so I bought a new one,put it on and forgot about it.
Car sat a weak while rain fell each day, drove it and squeal returns.
Remove belt, check alt for bearing wear and mabe a slight noise while
spinning,so I had another alt and put it on.same squeal above 3000rpm.
I had 3 different pulleys so I tried them all, same squeal.
I over tightened the belt, same squeal, I left it too lose same squeal.
I left the ps belt off and same squeal.
As far as line up goes, I've shimmed front and back, same squeal.
The only little thing I can c is that the alt hole that the 3/8 x 6 bolt
Goes through is a little large, mabe 7/16 , so it can get kinda
sideways, not much but some. Could this be it? Or any other ideas?
Been thinking of ordering a 3.25 deep grove alt pulley, but it didn't do
this before.
Anyone had a similar issue?
Ps and yes I have looked at the alt mounting brackets for cracks,
Can't find any.

[indymanjoe]

Belt width is what I found on mine.cant remember but one is supposed to be wider,alt or Ps.someone will chime in.

[1969GTO]

for what ever....I like the TOP COG belts.
I had a slight squeel I could barely here, went to a TOP COG...all better now

[Txbobcat]

Gates belts don't squeal either.

[455rebel]

Got it apart again looking everything over.
The only thing I can c is the hole in the alt that the long bolt
goes through is a little large, it lets the alt sit slightly off.
I am borrying another alt tomorrow to try.

[stellar]

I'm not sure what alt you have, but the 10DN and early 10SI alts had a 3/8 hole and later 10SI alts had a 10mm hole. A lot of large rebuilders would drill the 3/8 hole to 10MM and add a sleeve (shim) to put in the hole so it could be used for either 3'8 or 10MM mounts.

[455rebel]

I have gates belts now.
Mine has no shim.
Hole isn't round,it's kinda oval.
I'm trying another alt tomorrow, will post after install.

[72LuxuryLeMansLa.]

Originally Posted by Txbobcat

Gates belts don't squeal either.

Gates brand belts and hoses have always been my favorite brand, but the last alt belt I bought squeals like a stuck pig from 3000rpm on up also! I don't think they are sized correctly anymore........In my case though my 43 yr old 350 or actually 310ci engine (it has a zero compression #8 cylinder) doesn't see 3000 rpm for more than a split second as I accelerate up to 75mph to get onto I-10 these days so I can live with it until my new engine gets built and installed.

[Darth Menace]

Originally Posted by Txbobcat

Gates belts don't squeal either.

Oh I can't agree with that. I was told the gates belts don't squeel, but mine are brand new and do.

[PontGuy]

The PS belt has to be wider than the alternator belt so they ride over the crank and water pump pulleys at the same height. And I like TopCogs. This combo has always worked for me.

http://forums.maxperformanceinc.com/...=772212&page=3

[torqjunki]

Having some sqealing issues here as well. Quiet with a fan/clutch combo, but squeals when snapping the throttle with flex fan. I am going to try a thinner alt belt because it appears to be higher in pulley than PS. I have the stock accessory drive system for alt and ps and am amazed at how little belt wrap there is for the alt. it just kinda passes over the wp pulley with very little wrap. Sure this contributes to the issue.

[rohrt]

This is what I used.

I think the Alt belt is a 15xx belt and this what I used on the PS side. The ride a little higher then the factory belts but they are even, don't sequel and stay on.

Originally I used the proper size Gates belts but but I kept throwing the Alt belt when I raced the car.

[Blued and Painted]

What type of fan?
Normally the noise comes from a worn alt pulley. The belt runs low th the V and bottoms out where the inside surface of the belt is driving.

[torqjunki]

Here is a pic of my water pump pulley and belts. You can see that the alt belt is sitting higher than the PS belt. I can't find a belt thinner than what I have on there. I see everyone here recommending a Dayco 15480. It is the same size as the Gates 7480 I have on it. Could not find a Dayco 15480 anywhere. Dug around in my trunk and found one that I had for a spare. It is in good shape. Not sure why I went to the Gates, I know the Dayco has worked well for me. Installed the dayco and for now no sqeal. I need to drive it for a while to feel better about it. Only way I see to get my belts level with each other is to install a taller PS belt. Maybe it needs to be a 17XXX belt anyway.

[torqjunki]

OOps Forgot to post pic

[72LuxuryLeMansLa.]

Originally Posted by torqjunki

Here is a pic of my water pump pulley and belts. You can see that the alt belt is sitting higher than the PS belt. I can't find a belt thinner than what I have on there. I see everyone here recommending a Dayco 15480. It is the same size as the Gates 7480 I have on it. Could not find a Dayco 15480 anywhere. Dug around in my trunk and found one that I had for a spare. It is in good shape. Not sure why I went to the Gates, I know the Dayco has worked well for me. Installed the dayco and for now no sqeal. I need to drive it for a while to feel better about it. Only way I see to get my belts level with each other is to install a taller PS belt. Maybe it needs to be a 17XXX belt anyway.

I did the same thing until my "spare" broke and I went back to the squealing Gates........I need to go back to AutoZone and get another Dayco......

[77 TRASHCAN]

I sold auto parts for 13 years... I don't remember many GM cars of any make that used any other width than the 15 series Dayco or 7 series gates.

The screwy thing about this deal is, that it had NO squeal for quite a while, then decides to start making noise...

I'd polish the inside of the pulley w/ some 80 grit emery cloth. Do it to all the pulleys. If the belt is glazed, use the emery cloth on it, be careful...

My experience w/ noisy belts is that it's a pulley problem...the belt is seldom the culprit...
Hang in there Mr Rambler...LOL

[72LuxuryLeMansLa.]

Originally Posted by 77 TRASHCAN

I sold auto parts for 13 years... I don't remember many GM cars of any make that used any other width than the 15 series Dayco or 7 series gates.

The screwy thing about this deal is, that it had NO squeal for quite a while, then decides to start making noise...

I'd polish the inside of the pulley w/ some 80 grit emery cloth. Do it to all the pulleys. If the belt is glazed, use the emery cloth on it, be careful...

My experience w/ noisy belts is that it's a pulley problem...the belt is seldom the culprit...
Hang in there Mr Rambler...LOL

Unless it's a coincidence my squealing started when I changed the belts, not because they looked bad but as a maintenance deal.

[455rebel]

Originally Posted by 77 TRASHCAN

I sold auto parts for 13 years... I don't remember many GM cars of any make that used any other width than the 15 series Dayco or 7 series gates.

The screwy thing about this deal is, that it had NO squeal for quite a while, then decides to start making noise...

I'd polish the inside of the pulley w/ some 80 grit emery cloth. Do it to all the pulleys. If the belt is glazed, use the emery cloth on it, be careful...

My experience w/ noisy belts is that it's a pulley problem...the belt is seldom the culprit...
Hang in there Mr Rambler...LOL

Mr rambler, that's funny!
As a teenager ,when buying hot rod parts for my first car(1974 gremlin x
304 v8) the guys behind the counter at our only speed shop
Started calling me rambler boy, I was the only one in the county
Buying speed parts for a amc!!!

Back to the original problem, bolted another alt on tonight,
won't get to run it untill tomorrow.
Ps before all this started, the original belt that flipped and got replaced
was a little narrower than the replacement I now have that squeals.
I am looking for a narrow belt tomorrow!

[ta man]

Proper Alignment,deglazing of pulleys,proper alignment,tight brackets,proper alignment.