Corvair DiagramCorvair Photo
Corvair Center
home forum corvairs calendar links Corvair Podcast
California Corvairs
Clarks Corvair
Clarks Corvair
“CORSA"



Chevy Corvair License Plate
Chevy Corvair Chrome Wheel
Corvair Center Forum :  Corvair Center Phorum The fastest message board... ever.
Corvair Center 
belt tension
Posted by: joewryan ()
Date: November 19, 2020 06:43PM

I'm pretty sure this topic has been discussed before, but I could not find anything in search.

My 65 140 has an issue with the belt shaking at the entrance to the blower fan. The shaking causes the belt to move horizontally about 3/8" and allows the belt backing to hit the belt guide. This causes an annoying noise, and is wearing out the backing of the belt. BTW, this is a Clarks belt. I have tried various belt tensions, and a new belt, and all seem to allow the belt to do this. I replaced the tensioner, through a process of elimination, and no change. The harmonic pulley seems to be fairly straight, and the alternator pulley and bearing are new.

Any ideas?

Valencia, CA

1965 Corvair Corsa Vert

1954 Corvette Vert

1999 Land Cruiser Behemoth

Options: ReplyQuote
Re: belt tension
Posted by: RobertC ()
Date: November 19, 2020 07:57PM

Fan bearing “rough” - listen with a stethoscope.

Adjust belt guides on idler pulley / by fan bearing to slightly different positions.

Use a stick lubricant like Door-Ease on the sides of the belt.

Options: ReplyQuote
Re: belt tension
Posted by: 63turbo ()
Date: November 19, 2020 09:11PM

The other thing to check is how straight the fan pulley is... with the belt off, spin the fan, and keep your eyes on the sheaves. If you can see any wobble, pitch the pulley and get another.

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



Options: ReplyQuote
Re: belt tension
Posted by: vairmech ()
Date: November 20, 2020 05:05AM

The shaking of the belt is normal! That is made by the power pulses of the engine. The belt guides need to be about 1/4" away from the edge of the pulleys.

Ken Hand
Handy Car Care
248 613 8586

Vairmech@aol.com

Options: ReplyQuote
Re: belt tension
Posted by: dryenko ()
Date: November 20, 2020 07:08AM

Not normal for my builds and installations.
I find the fan pulley to be the main culprit.
They must run true at the grooves.
Constant width as well.
I have seen "squished" idler pulleys do this but it is rare.

Bob C aka Dryenko
Dobson, NC 27017

Options: ReplyQuote
Re: belt tension
Posted by: 66vairman ()
Date: November 20, 2020 08:52AM

Many belt posts over the years. Here are a few I recall.

The pulley belt grove must be smooth. Rusty, pitted, or rough spots cause issues.

The fan bearing assembly must be at the correct height.

Guides should NOT be too close to pulley as Ken stated.

And of course make sure the harmonic damper rubber is good. If cracked or hard it is time to replace.

The fan and pulley fit over a ridge on the bearing flange. It's a tight fit and if the parts were painted sometimes they don't seat properly (wobble).

Others may remember more.

Options: ReplyQuote
Re: belt tension
Posted by: corventure Dave ()
Date: November 20, 2020 09:01AM

Carburetor idle balance can also contribute to the belt shake. Especially with Powerglide equipped transmissions. At idle in gear there is a load on the engine. I always make PG equipped carb idle balance settings, in drive with the wheels well chocked.
I found that the spring loaded tensioners where the spring attached to the engine compartment were the worst and noisiest for transferring the power pulses from the belt.
Also make sure the throttle linkage is actuating and resting at idle properly.

Corventure Dave

Options: ReplyQuote
Re: belt tension
Posted by: joewryan ()
Date: November 22, 2020 02:17PM

Thanks everyone. I do see that the fan pulley is a bit wobbly.

Valencia, CA

1965 Corvair Corsa Vert

1954 Corvette Vert

1999 Land Cruiser Behemoth

Options: ReplyQuote


Sorry, only registered users may post in this forum.
This forum powered by Phorum.