View Full Version : Alternator Belt Squeal


Barry H
Jul 23rd, 01, 02:42 AM
Looking for some help on this issue. I just got the 350 back in the car and probably have 70 miles on it. Engine runs strong, but the alternator belt wants to squeal when I rev the engine quickly either from within the car or by hand operating the throttle. If I bring up the RPM's smoothly it does not happen, but thats no fun. Here's what I have done to no avail:
1. Tightned and loosened the belt, and put a little soap on the alt. belt.
2. Took off alt. belt, started car, no squeal when revved.
3. Thought that belt might be new and need some wear on the edges, so I took and roughened the belt slightly, still squeals.
4. I painted the belt grooves, so I took sandpaper and roughened the grooves thinking this would allow the belt to "catch" and again nothing.
I'm looking for help on this nagging issue, any thoughts would be appreciated. Thanks in advance.

Go69
Jul 23rd, 01, 04:31 AM
I hate to over-simplify but are you absolutely certain that you are attempting to use the right belt for your application? Don't trust the parts guy behind the counter-look up that part number and verify that you do in fact have the right belt as they vary in width. If you are running a belt that is too narrow there is nothing you can do to stop the squealing..

Barry H
Jul 23rd, 01, 04:39 AM
Thanks for the reply. I'm using the same type alternator belt as in the past, but I did increase the length slightly. It looks to fit very well, but it does have the "teeth" (for the lack of a better term)not a solid "V" shape. Thanks.

SY1
Jul 23rd, 01, 05:38 AM
Barry,
Did you replace the water pump when you had the engine out? The reason I'm asking is with several manufacturers and remanufacturers there are sometimes slight variances in the lengths of the pumps. I don't mean short vs long pumps, but variances between two pumps that are suppose to be the same length. This will cause your belt to be out of line with the other pulleys slightly and the alternator is usually the longest run on the belt. They make spacer kits to correctly set the water pump pulley back in line. The notched belt will actually run cooler and was a good choice, I don't think that's your problem. Again make sure your belt width is correct for the depth pulleys you have. Sounds like you've already tried the other things, have you tried another alternator? The rear bearings will fail in a lot of the new ones and can make a sound that is similar to a belt. But usually if it's a bearing it will be there all the time, not just when you rev the engine quickly.

Barry H
Jul 23rd, 01, 05:50 AM
SY1,

Thanks for the response. The water pump was replaced during the rebuild and everything seems to be lined up properly. I will double check the belt width versus the belt that I have versus what the parts store says I should have for a 67 350. Maybe there was a slight difference when I went with the longer belt, but I took the old one in and asked for the same belt only longer. Again thanks for the responses.

Everett#2390
Jul 23rd, 01, 06:23 AM
Take and spray WD-40 on belt.

Does it quiet down? If so, then tighten belt alittle more. Also, another item to check is alternator output(amps), is there a load on it for some mysterious reason?

I adjust for 3/8-1/2 in deflection on the longest leg of belt.

Everett

Joe G
Jul 23rd, 01, 07:31 AM
You might try switching to a Dayco "Top Cog" belt. The "teeth" are on the outside which seems to let the belt flex into the grooves better.
Worked on my 69.

joe

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SY1
Jul 23rd, 01, 07:54 AM
Barry,
If you need to shim you water pump pulley Mr. Gasket makes water pump and crank pulley shim kits that include shims of various thicknesses. Edelbrock, Stewart, Moroso and Weiand pumps are usually very close to stock. But many of the less expensive rebuilt pumps will be off a little.

camarko
Jul 24th, 01, 04:48 PM
Do You have a repro alt. bracket? Mine did and that was why mine squealed because the bend in the repro was not quite exact as the orig. Changed to orig and belts lined up perfect,end of squeals.

BrianW
Jul 24th, 01, 11:06 PM
I have a double pulley on my alternator and run two belts - no squeeling even without running them very tight - might be worth a try if all else fails and you don't have other accessories which prevent this

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68 SS

RickD
Jul 25th, 01, 06:14 AM
Take a metal straight edge and lay it across the two pulleys. You'll be able to see if they're in alignment. Does the belt show any shininess on one edge? I'm not a big fan of the inside toothed belts.

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Rick Dorion
69 RS Conv,355,M20,4.10's

kleen2000
Jul 25th, 01, 07:03 AM
It may be a the wrong series belt. I had th esame problem on mine. I had a 13 series and it wouldn't stop sqeuealing. I switched to a 15 series and it went away.

davidpozzi
Jul 25th, 01, 07:08 AM
If you have a heavy or large fan, that could be what is doing it, not the alternator.
What year camaro?
Don't ever spray any lubricant on the belt, you don't want the belt to be slippery.
You can test which belt is squeaking by spraying a little water on the belt.
Water will make the belt more squeaky for a half hour or so.
Painting the pulley won't be a permanent fix as the paint will wear off.
Try a different brand of belt.
I like the Gates belts best.
David

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