belt squeel

[prg machine]

I have a squeeling alternator belt when I romp on the engine. I am very tight on the adjustment. A friend reccomended a step down pulley. Sounded logical........ordered one from Summit and went to change it out with the stocke pulley on the alternator. The aftermarket pulleys hub replaces the alternator shaft bushing and fan. I called Summit and they said this wiould not work on a street engine since without a fan the alternator would overheat and sieze up
What is a solution and still staying with V belt drive?

[OrangeCrush1970]

you sure it's not your water pump bearings going bad?

[sameyrasmea72]

Did you replace the belt? Try some belt dressing i think its called from an auto store.

[Stocker]

Might be able to stop the squeal by replacing the belt with a new one. A (very) temporary fix -- and to prove beyond a doubt the belt is squealing -- is to rub a bar of soap against the belt while the engine is idling.

Disclaimer: Avoid the fan, don't wear loose clothing, keep your fingers out of harm's way etc. etc....

Edit: Just saw sameyrasmea72's advice for belt dressing. If you were here, I'd give you a nearly full can of it. It didn't work at all for me, just made a mess. Might have been the brand I bought though...

[Bob D]

What kind of radiator fan are you using? I had the same problem, tried several styles of belts including the notched ones to no avail. I ended up removing the fan and going with an electric one. No more squeal.

Bob

[PanelDeland]

I would suggest cleaning the pulley groove also.I usually use roll emery cloth and just buff the groove well.Cleaning with a wire brush first if it's really grungy.
Also make sure the belt is the right size.I assume the length is OK since you say it's tight but is the width right?V belts come in several widths and using one of a narrower width than the pulleys are designed for will cause squeal.A V belt should not bottom on the pulley but should run a 1/4 in or so from the bottom of the V.
Belt widths are designated as A B C or may be an L# designation.The V belts with reliefs(toothed) inside are usually considered to have better grip and are usually a better quality of rubber.
You may know most of what I posted but i thought some pointers and/or reminders might help.One company I worked for spent thousands on seminars to train maint people in the finer points of stuff like this.

Getting good grip from a belt without having to tighten the belt excessively will help with bearing and belt life.

[Sammy]

I have used the bar of soap method before it works well to determine which belt on a muti-belt pulley system is screaming @ you.

[Olden Days]

The last time I had one (belt) that wouldn't stop squealing ,it turned out the alt was going bad

[AustinScott]

I just went thru this same problem.
I bought a new belt & it still squealed. But it ended up being that the alt bracket was hitting the top of the alt (1st & 2nd picture)
not allowing me to tighten the belt fully.
So I had to move the bracket to the front of the alt( last picture). and it allowed me to tighten the belt fully. no more squeal

(click pictures to enlarge)

[prg machine]

new water pump..... Summit heavy duty high flow, alernator rebuilt and checks out fine, new aluminum crank pulley, nw notched belt that is the correct size
for the most part it only squeels slightly when I hit the throttle hard from an idle of say 700 RPM ifI have the engine up to 1200 or so and hit it it won't squeel
kinda annoying and I have cleaned the pulley real well


the larger stepdown pulley seemed logical, but we need fans on these things

[Green Machine]

I don't know if the K20 has the same water pump pulley as a C20, but assuming it does, The C20 has a smaller WP pulley than the 1/2 tons. It likely should not squeel, but ours squeels pretty good when wound out. We are going to replace it with one from a 1/2 ton, they are about 7 inches, same as crank pulley, that should slow the fan down enough and give it more surface diameter to grip, that should stop the squeel.

[70c10]

I got the same problem right before trans down shifts when I romp on it it will squeel real quick and loud!. I was thinking about a deep groove pulley.

[prg machine]

googled the problem and belt/pulley alignment seems to pop up.
Hmmmmmmmmmmmmmm????? something else to check I guess.

[Huck]

V belt issues~~~~~~~~~~~~when you think that it's all sorts of things like belt being wrong size, wrong pulley, warn or bad bearings, etc.~~~consider this~~~~~~The pulley cam actually get warn so that the "V" looses the flat nature of the sides of the V and instaed of having good belt to metal contact---you loose some of this frictional contact. Tightening the belt doesn't solve the problem. Using a small straight edge, carefully check to see if sides of the V are warn to start looking like alook like a "U". Replacing the pulleys and using a new belt of the correct size will solve the problem for years to come.

[WorkinLonghorn]

You can easily determine if it's the alt.belt slipping by reving the motor with everything off,and then doing it again with the headlights on high-beam,fan,radio(not AC),and if it squeals worse,then it's the Alt.belt. A new belt of the right size on clean pulleys won't squeal if tightened properly.If you still hear something,I'd agree with the guys above about a bearing or something.
Incidentally,about a year ago I bought a lifetime warranteed """""""Rebuilt!"""""""" Alternater from.........................Autozone! and guess what? It rumbled and screeched and I thought My engine was in big trouble,because how could a rebuilt unit be bad? Well it was a total POS so yours might be too.

[sleepertruck72]

This is interesting because I had a squeal in my old motor which I thought was all sorts of crap. I put in my crate motor with new everything except power steering pump. I thought that was causing my squealing. It is similar as described if I am idling and step on it real hard it will squeal. I dont notice while I drive on the street. Is this something to worry about ? The power steering works fine, I think. It doesnt leak at least. The alternator is new, belts new.

[prg machine]

Originally Posted by WorkinLonghorn

You can easily determine if it's the alt.belt slipping by reving the motor with everything off,and then doing it again with the headlights on high-beam,fan,radio(not AC),and if it squeals worse,then it's the Alt.belt. A new belt of the right size on clean pulleys won't squeal if tightened properly.If you still hear something,I'd agree with the guys above about a bearing or something.
Incidentally,about a year ago I bought a lifetime warranteed """""""Rebuilt!"""""""" Alternater from.........................Autozone! and guess what? It rumbled and screeched and I thought My engine was in big trouble,because how could a rebuilt unit be bad? Well it was a total POS so yours might be too.

This alternator was rebuilt right here in town by a local rebuuilder......not in Mexico or some piece work /sweat shop. I took it back to em and they ran it up on the test machine and it checks out great.........quiet as a mouse as well..............besides if the bearings were going out in the thing.......it would most likely make noise all of the time.. I am checking pulleys and alignment next........just haven't got backl to it......worked on a front bumper all day!

[GuyO]

I know this is an old thread, but I too am having the issue. New belts, new parts and belt dressing (what a mess) and still sqealing on initial startup, or when romping on it. The only thing left is the wider belt as PanelDeland suggests!

[gotchamel]

Having been through this{we all have}recently pulley alighnment is VERY crucial.Had what I thought was a alt belt squeal turned out to be a ps pulley just barely out of alignment,I mean just barely.I had no idea what a small tweak could sound like.

[70CHEVYBB]

how long has this problem been going on? I ran into a similar problem with belt squeel. I had the same size crank pulley but my water pump pulley had two different sizes on it. I took the power str belt off from around the water pump and squeel stopped.

[special-K]

Put a Z/28 deep groove pulley on.