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When flooring the accelerator I hear a squeak or something like it. The previous owner tells me it’s the alternator belt, and that it’s unavoidable with a high HP engine. I don’t mind the sound, but I do mind getting stranded somewhere because of a broken fan belt, so I want to try and fix it. After Summit’ing a bit, I’m confused. Serpentine or the like, that costs a fortune. Then I was thinking about a bigger alternator pulley, it’ll slow down the alternator, and it will also provide a bigger area of friction between pulley and belt, that might do it. But the pulleys that Summit shows confuse me a bit:
I.D., most are 0.642, but some are 0.650, are they really that close and won’t fit? What’s the I.D. of our standard Cleveland alternators?
O.D., I’d like to slow it down a little, but the ones they have are at least twice the diameter, it’s quite dramatic to slow it down 50%? Of course my Pantera is not a car that needs a lot of current for wipers and heated rear screens in stop and go traffic…

Has anybody had the same problem? And fixed it? I’d rather not spend a fortune on billet stuff that only I will see when I remove the engine plate. And will a bigger pulley scrape on the plate? I don’t want to modify that plate…
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I'm not 100% sure it's the belt, but haven't found what else it could be.

The belt is new, and it's tight. I've looked at alignment briefly, if consensus is that this is the cause I'll do it again.

Maybe not because of high HP, but this engine revs faster than any other big engine I've experienced (except my boss' Ferrari 599), and since it only makes noise when accelerating, that was my guess. But keep the suggestions coming...

Hello Mikael
I had this problem a many years ago on a Chevy Camaro. I could not figure out which belt was squeeling, was it the power steering or A/C belt. They were both new and both tight. Between the sounds of the motor and fan running.....who could tell. My thought process was if I can't figure out what is squeeling, maybe I could figure out what was NOT squeeling. So I used a bar of soap. With the engine running at idle, I SOFTLY held the bar of soap against one side and then the other side of the A/C belt. Then Reved up the motor and still had the squeel. So I soaped the power steering belt and that stopped the squeeling. With that I pulled of the power steering belt, scrubbed the both pulley grooves for the belt. I took a steal yard stick and laid it accross both pulleys to verify or at least try to verify their alignment. From what I could see, I found the alignment to be pretty good. So I cleaned the belt and put it all back together. And it didn't squeel. A couple of week later the squeel came back. So I sat and watched the A/C belt as I reved the motor. The belt didn't hop around or attempt to cant or off angle it'self off to one side as it approached the next pulley, it looked even looked like the V of the pulley matched the V of the belt. ..... in the end I took a can of belt grip, sprayed it into a rag and slightly wiped down the inside belt area between the pulleys. Fired it back up and no more squeeling...................... in fact no more squeeling for about 3 more years, at that point I took the car swiming one night.......but that's another story. Good Luck....... Doug.H #6434
Belt squeal is pretty telling, can also create that noise by increasing the load on the ALT by turning on headlights, A/C, etc and reving the engine a bit.

I would pull the cover and check the pullys' and belt for glazing (looks shiney and cooked)and alignment with a straight edge. If the pully is glazed but not worn (the V side walls of the pully should be straight)they can be sand blasted to get the glaze off, the belt must be replaced. Also, these engines are known for pully misalignment due to the mounting brackets and length of belt. See pic of how far mine was out of alignment! I ended up heating the brackets to bend back into shape. I have a higher amp alt that now runs without ruining belts every month. Am still thinking of installing an idler pully to help wrap the belt a bit more on the Alt pully.

Sorry about Picture size!

Alignment before (squealer)

Heating lower bracket to realign (on car)

Cooled and aligned

If the pully is glazed, hopefully it is just the Alt pully, I ended up blasting all of my pullys and powdercoating them.

Anyway, good luck and let us know what you found out.

Thanks for all the help. But I just found out the noise isn't the belt Smiler

On a drive today I did something I don't think any driving instructor has ever recommended: Look in the mirror when you floor the accelerator. But I did on a deserted road, and I've found that the noise is present exactly when the secondary throttles on my double-pumper opens and closes. Unless someone disagrees, I wouldn't be concerned about that.
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