I hesitated to post this question as it seems so simple, but it's driving me crazy. My '55 TBird has an alternator conversion. The conversion is a Casco kit and I assume the alternator is from some GM product.  The alternator in the kit has a single groove pulley. I do not run a fan off the water pump. The problem is my alternator belt squeals on start up.  It never squeals when driving.  I've tried new belts and tightening the belt numerous times, but I can't seem to stop the noise.  I've tried all kinds of belt gook with no real results. It's not a significant problem, but it is annoying. I thought about changing the pulleys to run two belts, but I'm don't know if the parts are available. Anyone had this problem and solved it?

I've found this to be (given the pulleys are aligned pretty close) either the belt is too narrow for one or more pulley than stock (riding on the bottom of the tapered groove) or something is really tough to turn when cold.
Can you tell which pulley is making the noise? One ? All ?


1936 Ford 3W Coupe : 56 T-Bird 312, 47 Packard 3 speed, 40 juice brakes.
1968 Merc Cyclone FB GT 390, Getting a better front clip!
1977 Ford F-250 Supercab RWD Explorer Long box.
1976 Chev Camaro RS LT
Future rebuild : 1949 Ford F-1

... mmm ...

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It is a very pretty engine I may be wrong but it appears the pulleys are somehow askew..it is hard to judge by the photo but somehow the alignment between the alternator and water pump is off. You want to rub a candle on the belt as a dressing to help with the squeal until you really figure out the issue.

Two things to mention (as I have had this similar trouble with an alternator install)...

1. Could be that the "V" of your belt - meaning the angle of the sides of the belt itself - are not mating with the "V" of your alternator pulley. I would check for that first.

2. I would recommend that you remove the belt and use sandpaper to roughen up the grooves of all 3 pulleys so that you get better friction when the belt engages. 

Daniel Jessup

Lancaster, California

aka "The Hot Rod Reverend"
check out the 1955 Ford Fairlane build at www.hotrodreverend.com

Just from the photo it appears the belt runs low in the water pump pulley and slightly high in the alternator. Does this happen all the time or right after start up when the system is asking for more load? That does make a difference. Daniel has the best suggestion. I have “roughed up” pulleys before with 120 grit from a roll and it’s alway the older pulleys like the pump or crank doing it because they are shiny smooth and warn. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

I am having the same problem with the power steering belt on my 292.  It always squeals on cold startup but the noise goes away after running the engine for a minute or so.  If I start the engine again after it has warmed up there is no squeal.  

The noise only happens on startup and it goes away quickly.  The generator never did this.  In the photo above, the belt was misaligned on the crank balancer pulley.   I fixed this and installed a new belt, but the squeal remains.  I believe the belt squeal is caused by the additional load of the alternator and a groove depth mismatch between the alternator pulley and the crank and water pump pulleys.   I have tried a few different belts with no effect. I'll try to roughen up the alternator pulley and see if it helps.  Thanks!

Phil.....try roughing up the pulleys.  I used a small file to rough up the edges of the "V" in my power steering pulley and this solved the problem.  

It looks like the water pump pulley may be intended for a 1/2" belt.  The alternator pulley should be larger than about 2 3/8" diameter for a 3/8" belt, to prevent the belt from "puckering," is what Powermaster said when I was researching pulleys a years ago.



Lawrenceville, GA