Fan Belt Squealing

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Clutch Powers
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Fan Belt Squealing

Post by Clutch Powers »

The clutch cable recently broke in our '65. It took about 3 weeks or so to get it figured out and replaced. When we started the car again, the fan belt started squealing. We tightened it and it was fine.

The next day it squealed again, so we readjusted and it was fine. This has been repeated the last four days.

From what I've searched and read on the forum, the pulleys may need cleaning and the belt may need spraying with silicone.

Is it possible the belt is stretching? Or is it likely we are not tightening the bolts enough? I was trying to be careful not to overtighten anything, but now the rear-most bolt doesn't seem to want to tighten. Why would that be?

I'll check the pulleys when my son gets home with the car. It sat for months while we worked on the paint and the belt was fine until recently. It hasn't come off and doesn't seem to be twisted.

Also, what does the silicone do? Shall I just spray the belt with it; or the pulley gooves too?

Thanks!
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terribleted
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Re: Fan Belt Squealing

Post by terribleted »

Sounds like either the adjustment is slipping (forward bolt on the idler pulley not tight enough?), or some bearing is rapidly failing. Remove the belt and make sure the alternator fan, idler pulley, and fan rotate freely. Then adjust the belt until it is tight enough that the alternator pulley can just barely be slipped in the belt by hand. Be sure the belt is a proper replacement as well, there are many so called replacements (from parts stores and other places) that are really not correct.
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Clutch Powers
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Re: Fan Belt Squealing

Post by Clutch Powers »

Thanks Ted. The belt that's currently on there is a Clark's belt and looks to be in good shape.

I looked closer at the pulleys and they could use some cleaning. We'll get to that tomorrow.

I probably have some silicone I can spray on the belt as well.

I'm not sure why that rear bolt won't tighten though.
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flat6_musik
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Re: Fan Belt Squealing

Post by flat6_musik »

I've heard of people spraying a minute amount of lubrication spray on a fan belt that's "chirping", but to spray it with silicone because it's probably slipping/squealing?.......naw, I wouldn't. I think friction here is your friend. Possibly your adjustment is loosening up, that's my guess. Check and see if you've got a nice FLAT flat-washer behind the adjuster nut on the grooved area of the idler pulley. Don't go bananas on it, but it should be pretty tight.
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terribleted
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Re: Fan Belt Squealing

Post by terribleted »

Clutch Powers wrote:Thanks Ted. The belt that's currently on there is a Clark's belt and looks to be in good shape.

I looked closer at the pulleys and they could use some cleaning. We'll get to that tomorrow.

I probably have some silicone I can spray on the belt as well.

I'm not sure why that rear bolt won't tighten though.
If it gets kinda tight and is then spinning the threads are stripped. If it gets tight but is not holding the idler tight perhaps the bolt is too long and hitting the bottom of the threaded hole (replace with shorter bolt or add a washer under the head to make it effectively shorter). I also have never seen any reason to spray a proper belt with silicone.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia
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bbodie52
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Re: Fan Belt Squealing

Post by bbodie52 »

If the bolt you mentioned will not tighten and keeps turning, the aluminum threads may be damaged and stripped. Also, as shown in the illustration below, fan belt internal construction includes multiple reinforcement strands that are hidden from view and are embedded inside the belt. These strands can become damaged (often after a belt flips). The belt appears to be OK, but the hidden damage allows it to stretch because it lacks the designed inner strength reinforcement that normally permits flexibility while limiting stretching and maintaining the specified length. If you have a spare belt (always recommended in a Corvair) you might try replacing the belt and see if that clears your problem.

:link: http://www.corvair.com/user-cgi/catalog ... IN&page=14
Image

The correct amount of belt tension permits some slight slippage of the generator/alternator pulley when pushing the generator/alternator fan blades by hand.
Brad Bodie
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Image 1966 Corvair Corsa Convertible
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UNSAFE
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Re: Fan Belt Squealing

Post by UNSAFE »

SILICONE !!!!!!!!!!!!!!!!!!!!!!!!

Don't be afraid to lay it on heavy . I soak my belts in it before using .

You're sure it's not the fan bearing squealing ???
Kevin Willson
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Re: Fan Belt Squealing

Post by flat6_musik »

UNSAFE wrote:I soak my belts in it before using .
LOL Why?!?
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Re: Fan Belt Squealing

Post by UNSAFE »

LOL Why?!?
You may be jesting - but it makes a world of difference in belt retention at high RPMs or speed shifting .

It seems even more important when breaking in a new belt . If they grab too much they will climb right out of the groove .

I use the heavier bodied "Pure Silicone " which is much like food grade . The usual FLAPS stuff is usually thinner .

I really do pre-soak the belts for future use .

I spray my belt and my pulleys and may re-spray occasionally if I'm at a track event .

I do keep a can in my car .
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Kevin Willson
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flat6_musik
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Re: Fan Belt Squealing

Post by flat6_musik »

UNSAFE wrote:
LOL Why?!?
You may be jesting -
Oh, not at all......I seriously doubt many corvair owners would know of this. I dunno, I still can't see myself doing it. Maybe a special spray-on belt dressing......
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UNSAFE
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Re: Fan Belt Squealing

Post by UNSAFE »

Maybe a special spray-on belt dressing......
Belt dressings cause the belt to grip -- liquid dish soap will do the same thing .

On the Corvair you want the belt to slip instead of grip .

Trust me on the silicone :cool:
Kevin Willson
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Clutch Powers
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Re: Fan Belt Squealing

Post by Clutch Powers »

We took a closer look this evening at the belt pulleys. We have now determined that the rear-most bolt is somewhat stripped out.

Is this common? What is the best way to resolve this?

Thanks!
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Re: Fan Belt Squealing

Post by davemotohead »

You need to install a Heli coil or Time sert to repair the threads! I also spray/soak my belts with silicone, you want slide action and not grab action as unsafe says,I have not thrown or broke a belt in years and the one on my yellow car has been in service since 1989!! it also keeps them from drying out and breaking :tu:
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Clutch Powers
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Re: Fan Belt Squealing

Post by Clutch Powers »

Thanks Dave. I had to take my wife to the airport tonight and when I got home, the Corvair was gone - but I take that as a good sign.

The steel wool and can of spray silicone had been moved, so my son must have gotten it put back together and running again.

I'll have to look into the helicoil. What size would I need to get?

Thanks!
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terribleted
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Re: Fan Belt Squealing

Post by terribleted »

The proper size for the bolt which should be a 3/8" 16 threads per inch.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia
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bbodie52
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Re: Fan Belt Squealing

Post by bbodie52 »

Brad Bodie
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