Alternator belt screeching

[Gaz64]

350 amps? Like to see that spec.

Chrome pulleys always slip, does the belt drive on the V only? If it bottoms in the pulley, you'll never stop it squealing.

[BAsque1]

I just got back from a ride and the alt belt broke, I overheated but I was about a mile from home tks God. I guess the pulley will need serious roughening. Here is a picture of the alternator.

Lou

[Steve Gallegos]

I put a new belt on mine and it does belt does the same thing when I start it up for about 10 minutes then goes away, I also have a chrome pulley. I'll try the tooth paste and see if it works.

[diverrick]

I am guessing he meant 35 amp system Heck a 60 amp system is alot. The number being thrown around is way out of whack.
if he does have that big an alternator, no wonder the belt slips!!!
Must be as big as half a house.

[BAsque1]

Originally Posted by Steve Gallegos

I put a new belt on mine and it does belt does the same thing when I start it up for about 10 minutes then goes away, I also have a chrome pulley. I'll try the tooth paste and see if it works.

Let me know your results Steve, I am going to use lapping compound on the pulley or valve grinding compound.
Lou

[Barnsnake]

At full output it will take 5-6 horsepower to turn that alternator. That will be tough with a narrow belt and a chromed pulley. A machine shop may be able to sandblast the pulley, or knurl it, or grind some texture into it without changing the groove dimensions too much.

It might be easier to get ahold of the alternator company and see if they can send you an un-plated one.

[twin turbo]

I used a bar of ivory soap, just held it against the running pulley for a few seconds and the squeal went away.

[Jaydee]

350 amp, maybe it's a hybrid?Cobra prius. try WD 40. That'll shut it up. It'll soften the belt.
JD

[BAsque1]

Originally Posted by Jaydee

350 amp, maybe it's a hybrid?Cobra prius. try WD 40. That'll shut it up. It'll soften the belt.
JD

Hey Jaydee, (It's Blue....!!!!!) just kidding Bro, I will try many things, unfortunately I paid big bucks for this custom built alt and I will have to find a solution. My first try will be lapping compound on the pulley groove.
Tks
Lou

[vector1]

I think you better search for a double pulley setup, there looks to be enough shaft on the front of the alternator for one. Or you can go with a cogged pulley system, or reduce the amperage of the alternator.

You can use a manual switch for the fans, turn it on after the engine is running to reduce cranking & fan amperage together which is what I do, especially when using a small battery.

Under cranking the battery is supporting the starter and fans and whatever else electrically is running--microwave, etc.

[BAsque1]

Ok guys here is an update, the belt that was there was old and in bad shape, I thought it was good at the time.

I changed it for a new belt a tad wider and the screeching went away until the temp of the engine reached and passed 200 degrees. I am going to try the toothpaste and perhaps lower the kick off temp of the fans so they go on at 185-190 degrees.

If this does not work I will use valve grinding compound on the pulley groove to see if this takes care of it.
If anyone has any other thoughts other than changing my alternator, suggestions are welcomed.
Lou

[itstock]

How loud is it over the sound of the exhaust? My belt screeches as well, though it's very low in volume (obviously high pitch). The only time I really hear it is when I'm idling next to another car or barrier of some sort. It's not loud enough to hear while driving, and it's not loud enough for someone outside of the car to hear while driving by.

FWIW, I also have the polished pullies and have tried a new belt with no change. I've become perfectly fine with living with the sound.

[Gaz64]

Originally Posted by BAsque1

Ok guys here is an update, the belt that was there was old and in bad shape, I thought it was good at the time.

I changed it for a new belt a tad wider and the screeching went away until the temp of the engine reached and passed 200 degrees. I am going to try the toothpaste and perhaps lower the kick off temp of the fans so they go on at 185-190 degrees.

If this does not work I will use valve grinding compound on the pulley groove to see if this takes care of it.
If anyone has any other thoughts other than changing my alternator, suggestions are welcomed.
Lou

A tad wider? Did the old belt run on the bottom of the vee?
If so, that's 90% of the screeching problem.

What is the true alternator output in amps?

Surely a 120 amp would be ample.

[CHANMADD]

The problem will persist untill you chuck that chrome pulley.............an aluminum set will work , but take note I said a ..set..not just one....and that alternator is putting a drag when the fans kick in....maybe you need a bigger battery..........the large alternator cannot help the engine start...it only charges the battery....i

[BAsque1]

I just ordered a larger diameter pulley in machined aluminum from March Performance Pulleys and this supposedly will take care of the problem. Will keep you all posted of the progress.
Lou

[BAsque1]

Ok new MArch Perfomance pulley installed (bigger diameter Aluminum) worked like a charm, temperature went to 200* the fans kicked on as supposed to NO BELT SCREECHING YAY!! problem solved.

[Ron61]

Lou,

That is great. Now sell the chromed one to someone who doesn't hear so well.

Ron

[CHANMADD]

Gotta love it when a plan comes together.!!!

[BAsque1]

Tks Guys, Ron61, hey I have a pre-owned chrome alt pulley sell it you cheap...
It took me less time to solve this problem than being able to upload pictures to CC albums...

[Ron61]

Lou,

I have had a enough trouble getting the Coupe back into safe running order. I don't need squeaky belts to go with the rest of the stuff. Scuff the chrome off the inner track of the pulley and save it for when the aluminum one falls off.

Ron