Cooling fans and squealing belts

[xaircav]

As you know I have a '62 283 in my '53 five window. I recently did an alternator conversion. If the cooling fan is installed and I blip the throttle the fan belt squeals. I have tried several different belts, a six blade fan and now a four blade 15" low drag fan. Removing the fan removes the squeal so the extra weight of the rotating mass must cause the belt to slip. I'll need to put the fan back on when the weather warms up but I'm sick of the piglet sound. Doesn't squeal at idle or cruise.

[Clay54]

Please don't take this the wrong way, but have you considered/tried a belt dressing? I have a '84 Suburban diesel and the belt for the AC not only bounces when the compressor comes on but also at times will squeal. I found some belt dressing (don't remember the brand) at the auto parts store and stopped the squeal. Still bounces but that has not been an issue. Clay

[mr48chev]

I'd say it was improper belt tension or possibly the wrong belt width that is causing the problem rather than fan, number of blades or what not.

On my 77 1 ton the belt squeals just after the truck starts if I have to crank it too long and the alternator is charging hard to recharge the battery and that may be the case on your truck. The alternator might just be working harder at recharging the battery than the generator did.

As Clay54 mentioned does the belt seem to bounce a bit when the truck is running? It simply may not be tight enough.

Also are the pulleys all in perfect alignment as being off even a fraction might cause the squealing due to not being seated in a pulley right.

[xaircav]

No matter how tight the belt is it squeals. I checked pulley alignment with a straight edge, tried belt dressing and several width belts. Mr. 48 may be onto something about alternator draw. I went from a 20 amp generator to a 63 amp alternator. What does guys think of a fan with a thermal clutch?

[_Ogre]

piglet sound

lol

post a pic of your alternator mount, it may not be rigid enough and flexing under load (acceleration)
look at the mount and belt when you blip the throttle
chances are if you beef up the alternator mount the ''piglet sound'' will go away

if you are using the old generator bracket, this type of bracket is notoriously weak



i could probably pull my motor using either alternator or ac compressor mount

[Highsider]

Originally Posted by xaircav

No matter how tight the belt is it squeals. I checked pulley alignment with a straight edge, tried belt dressing and several width belts. Mr. 48 may be onto something about alternator draw. I went from a 20 amp generator to a 63 amp alternator. What does guys think of a fan with a thermal clutch?

I went to a 97 amp alt and use a skinny, stock-style, v-belt and I have no noise at all...ever.

Sayin'