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Fan belt ‘cracks’
Posted by: DaveO90s4 ()
Date: February 28, 2019 11:36PM

Hi all,

I noticed that my fan belt had cracks in two separate places and at each crack was only holding together by the outer side rubber. Is there a known reason for that type of wear that I need to know about to ensure that doesn’t happen again? (I’m aware of problems of excessive tension - am pretty sure it wasn’t too tight). Have now replaced it with a new one.

Thanks

DaveO

Dave O

1975 Porsche 914 with 140 HP Corvair reverse rotation engine, zenith 40 TINS, Otto 20 (or 30?) cam, etc, Australia

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Re: Fan belt ‘cracks’
Posted by: Lane66m ()
Date: March 01, 2019 03:17AM

Too much heat in engine compartment?

Al Lane
Ellabell GA

1966 Monza Coupe, 110 hp, 4 Spd
1968 Camaro SS Coupe 350 CI 295+ HP PG
1964 Greenbrier Deluxe, 6 dr, 80 hp car engine, PG
2015 Chevrolet Malibu 2LT
2018 Chevrolet Silverado LTZ Z71 Centennial Edition
1947 Farmall A tractor 15 hp


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Re: Fan belt ‘cracks’
Posted by: DaveO90s4 ()
Date: March 01, 2019 03:24AM

Hi Al. Thanks for the reply. Maybe heat soak - but don't think so. Max cyl head temp is 300C, engine oil max 110C, max crankcase temp with heat soak <90C. Maybe just a 'New Old Stock' belt?? Fingers crossed.I've now only got one spare belt - hard to find 3VX 560 belts in Oz - the equivalent all seem to be 'ribbed'.

Cheers

DaveO

- You'll see in another post that I trashed the new replacement!!! That's another story...

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Re: Fan belt ‘cracks’
Posted by: Lane66m ()
Date: March 01, 2019 03:28AM

Morning and evening Dave. If it was a NOS belt 50 years old, yep that was the cause. Rubber was aged and went past it life. Ever seen any other auto belt go 10 years on a vehicle without cracks.

Al Lane
Ellabell GA

1966 Monza Coupe, 110 hp, 4 Spd
1968 Camaro SS Coupe 350 CI 295+ HP PG
1964 Greenbrier Deluxe, 6 dr, 80 hp car engine, PG
2015 Chevrolet Malibu 2LT
2018 Chevrolet Silverado LTZ Z71 Centennial Edition
1947 Farmall A tractor 15 hp


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Re: Fan belt ‘cracks’
Posted by: joelsplace ()
Date: March 01, 2019 03:40AM

I've got a 2001 LeSabre with the original belt on it. Still looks nice. I probably shouldn't have said anything...
1981 C10 original belts and hoses made it until about 6 years ago.

Joel
Northlake, TX
4 Ultravans, Lost count at 100 Corvairs...

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Re: Fan belt ‘cracks’
Posted by: Lane66m ()
Date: March 01, 2019 03:48AM

Synthetic compound belts of the 2000 decade versus rubber compound belts of the 60s?

Al Lane
Ellabell GA

1966 Monza Coupe, 110 hp, 4 Spd
1968 Camaro SS Coupe 350 CI 295+ HP PG
1964 Greenbrier Deluxe, 6 dr, 80 hp car engine, PG
2015 Chevrolet Malibu 2LT
2018 Chevrolet Silverado LTZ Z71 Centennial Edition
1947 Farmall A tractor 15 hp


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Re: Fan belt ‘cracks’
Posted by: DaveO90s4 ()
Date: March 01, 2019 03:52AM

Hi again Al. On my car (engine in 914) it is simply not possible for me to observe the vertical alignment of the belt as it runs between the idler pulley and the crank pulley. Would you be able to tell me - when the belt is dead vertical and in perfect alignment - the distance between the idler pulley and some other fixed position atop the engine? I would then use that distance as a target distance when adjusting my idler pulley. I’d set the idler to get the correct belt tension and I’d know the resulting misalignment (from vertical) by the variance between your ‘perfect’ alignment distance and whatever equivalent distance I end up with.

I’m hoping you have an engine complete not in car with a new oem bekt that you could do this for me.

If anyone else could do this for me then that would be appreciated too.

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Re: Fan belt ‘cracks’
Posted by: DaveO90s4 ()
Date: March 01, 2019 04:11AM

To follow up on my immediately previous post - where would one take the measurement that I'm after? If all corvairs have the same diameter fan pulley then how about measuring the distance between the two closest points of each pulley (idler and fan)? Or if not all fan pulleys have the same outer size, how about between the closest point of the idler pulley and the dead centre of the fan pulley?

I hope that I am not imposing. If so, my apologies. If I were to get several replies from different people that would be excellent.

Night time here. I'll go to bed now and hopefully I'll have a few responses and data points by the time I wake tomorrow.

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Re: Fan belt ‘cracks’
Posted by: steve c goodman ()
Date: March 01, 2019 07:37AM

Dave the reverse turning engines I deal with use
3VX-560 Gates belts with no problems of fit. I
know very well how difficult it is to look at
crank pulley on the 914 because of placing of
the engine to the bulkhead.

Correct pulley on alternator has been a topic for
you in the past and I presume you have correct
diameter, I seem to recall you found a 64 with
the shield which is what I always use on reverse
turning engines.

I have fabbed a belt guard on the fan shroud on
opposite side of top pulley on a couple of the
engines but not on every one. I have also seen
a couple of instances where guys have fabbed a
guard between the crank pulley and alternator
pulley but I have never needed one on my engine
conversions.

Ensure your crank pulley is running true, a very
tiny amount of wobble will cause the belt to
vibrate and then jump off pulley. GOOD LUCK

best wishes, Steve
Rear Engine Spec. Inc. Golden, Colo.

1962 spyder 3.0L turbo---1965 Crown V8
1967 monza 110/4---1968 monza 110/4
1971 amante gt 110/4
CORSA/RMC/PPCC

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Re: Fan belt Idler pulley measurement
Posted by: MattNall ()
Date: March 01, 2019 08:06AM

Dave

Fan pulley belt guide.... pivot bolt.... center of head..

Idler pulley..... horizontal plane of shaft... outer edge / rim of distributor side of pulley..

5.5" / 140 mm [ inches times 24.5 ]





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Fan belt ‘cracks’
Posted by: Frank DuVal ()
Date: March 01, 2019 08:18AM

Quote
Dave
Max cyl head temp is 300C

!!!!!!!!!!!!!!!!!!!!!!!!!! eye popping smiley I do hope you mean degrees F.grinning smiley

I think you are overthinking this. Distance between fan pulley and idler pulley will vary with stretch of belt. DIstance between fan pulley and alternator pulley should never vary engine to engine more than 1 or 2 mm. Insignificant variation. If this varies while spinning the pulleys, one of them is bent.

56" belt 3/8" wide and tighten until you can still turn the alternator fan (or generator on earlies still running them...) with your fingers applying force.

Age cracks. Maybe belt was old when you bought it.

Yes to 3VX560 being a good one. So is Clarks Ultimate to me. But, what brands are available down there? And need to convert inches to mm for local stock? 1422 x 9.5 or so.

Frank DuVal

Fredericksburg, VA

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Re: Fan belt ‘cracks’
Posted by: WalterElias ()
Date: March 01, 2019 02:13PM

V-Belt Supply Wrapped belt less than $5.00 each. I order them in quantities of 10. Replace the belt once a year whether they need it or not. Problem solved.

V-Belt Supply 3V560

Dan Kling
1961 Greenbrier Deluxe, 110 HP, 4spd, 3.89 stump puller
1963 Spyder Coupe, restored, converted to 4spd Saginaw
1967 UltraVan #299, The migration has begun, we're on the road again......Save the Whales!

Photos of our Greenbrier, UltraVan and work-in-progress @

[www.flickr.com]

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Re: Fan belt ‘cracks’
Posted by: DaveO90s4 ()
Date: March 01, 2019 02:18PM

Hi Gents, to reply to your kind replies:

Steve. Yes, correct '64-only alternator pulley. All was good, no belt problems at all, until I changed out the about-to-break cracked belt. I hope this is simply a matter of operator error. I had thought I was beyond my earlier belt problems and was on a journey to discovering completely new problems. Sent you a much too long PM.

Matt. Thank you very much for that datum point measurement. Just what I needed. I reckon my idler with correct-ish belt tension is about 1/2" to 3/4" closer to fan pulley than your measurements. As a result the belt is arriving (reverse rotation, for those reading along) at the crank pulley at an angle. Now the new belt has done 50 miles or so maybe I can tighten it a bit to get better crank pulley entry alignment without over tightening the belt. Cold:- I can very very easily turn the alternator pulley with one finger. So maybe it is a bit too loose.

Frank. Yes, degrees Farenheit for cylinder head temps. My mistake. I understand that alternator position is absolutely fixed and idler position is variable with belt wear etc. What I was trying to establish is the idler position when it is set so that a belt is then in perfect alignment to leave the idler pulley (reverse rotation) to arrive at the crank pulley dead vertical (irrespective of belt tension). This is because with my engine in my 914 it is simply impossible to see this properly. I've not yet been able to find a source for 3VX-560 belts here in Australia so I end up importing them for US. Works out at about $50 Aus per belt. I may be over thinking things - but I just want to get over this problem and enjoy the 914 with all the extra HP I've now got. It really is a great combination when going properly.

Best regards to all

Dave O

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Re: Fan belt ‘cracks’
Posted by: MattNall ()
Date: March 01, 2019 02:26PM

Do belts SHRINK when aging on a shelf???





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Fan belt ‘cracks’
Posted by: 63turbo ()
Date: March 01, 2019 03:12PM

Dave O-
I've been following your posts on this for quite some time, and it wasn't quite
clear to me why you were having so much problem with this, but I get it now, looking at my own car... the issue is for your car running opposite, your idler
and alternator relationship is backwards now... your idler needs to be "straight up" and tangent to the crank pulley, and your alternator needs to be "forward" ever so slightly to have the same relationship with tension that a conventional rotation Corvair would have. You might be able to correct this somewhat by getting an aluminum idler (if you don't already have one) and have its v-groove cut somewhat deeper, allowing you to bring the idler "back" farther, and possibly enlarge the bolt holes on the alternator and push it "forward" towards the fan pulley somewhat, or perhaps a different, adapter mount for the alternator could be rigged to accomplish the same thing.

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

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



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Re: Fan belt ‘cracks’
Posted by: DaveO90s4 ()
Date: March 01, 2019 03:47PM

Hi Kevin. Yes, your comments re idler : crank pulley alignment are I think correct. But there is something else going on. Other reverse rotation engines don’t have the problems I’m experiencing. So there is something atypical with my set up. As purchased, the alternator pulley was not the right one. It was too small. I’ve corrected that. I’m wondering now if the previous owner also fitted an incorrect (oversized?) idler pulley. A smaller diameter idler pulley would allow me to get the correct belt tension coupled with correct alignment for clean belt arrival at crank pulley.

As it is now, with a new belt I’m in the middle of fitting (was commanded to stop for coffee with my wife ha ha), the idler pulley obscures the head of the belt tension adjustment nut. Crazy.

Or is it simply that my brand new 560 belts too short?

I’ll keep at it and will solve it one way or another.

Best regards

Dave

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Re: Fan belt ‘cracks’
Posted by: Ratt643 ()
Date: March 01, 2019 04:10PM

Had a Gates heavy duty belt shred on me coming back from Pensacola on I-59. That belt wasnt that old but think the 90 turns really wreak havoc on a belt. i put on my spare Clarks belt but was apprehensive about heading on home without another spare. Took me an hour trying two different part stores near where we were to find a belt. No one had a 57 inch belt!! When you ask the kid behind the computer for a 57 inch belt, he looks at you like you've lost your mind! Next road trip, there will be two belts instead of one!


1964 Monza Coupe

Maryville, TN
U.S. 129 The"Tail Of The Dragon"

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Re: Fan belt ‘cracks’
Posted by: DaveO90s4 ()
Date: March 01, 2019 04:28PM

Hi Ratt643,

57” belt? Or is that just a typo and you meant 56”?

I’m beginning to think that the simple solution to my problem is a marginally longer than stock belt. A 57” may be on my horizon.

Am almost over trying to figure out the root cause, am about to jump to solution mode.

Dave

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Re: Fan belt ‘cracks’
Posted by: Ratt643 ()
Date: March 01, 2019 05:08PM

DaveO90s4 Wrote:
-------------------------------------------------------
> Hi Ratt643,
>
> 57” belt? Or is that just a typo and you meant
> 56”?
>
> I’m beginning to think that the simple solution
> to my problem is a marginally longer than stock
> belt. A 57” may be on my horizon.
>
> Am almost over trying to figure out the root
> cause, am about to jump to solution mode.
>
> Dave


I use a 57 inch belt. They tend to have a straighter shot down to the balancer from the idler pulley.


1964 Monza Coupe

Maryville, TN
U.S. 129 The"Tail Of The Dragon"

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Re: Fan belt ‘cracks’
Posted by: MattNall ()
Date: March 01, 2019 05:27PM

3/8" by 57??? Not a 7/16 -1/2!!!





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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