Need help with '66 L36 A/C pulley/belt application

[Michael J.]

I am having trouble getting the Quanta suppled belt, allegedly correct, to fit on my '66 L36 A/C compressor. It is about an inch too long and thus will not tighten. It is a 3/8" wide belt, and my A/C pulley is 5 1/2" in diameter. with a deep groove that the belt sits low into. Does anyone know if that is the correct belt width and the correct A/C pulley diameter? Thanks for any help.

[Joe L.]

Re: Need help with '66 L36 A/C pulley/belt application

I am having trouble getting the Quanta suppled belt, allegedly correct, to fit on my '66 L36 A/C compressor. It is about an inch too long and thus will not tighten. It is a 3/8" wide belt, and my A/C pulley is 5 1/2" in diameter. with a deep groove that the belt sits low into. Does anyone know if that is the correct belt width and the correct A/C pulley diameter? Thanks for any help.

Michael------


The original belt was GM #3889376. It's specifications according to GM are 15/32" wide X 45-3/4" long.

[Michael J.]

Re: Need help with '66 L36 A/C pulley/belt application

Thanks much Joe, I saw your reply to an earlier similar thread, and seems you indicated it was discontinued in 1970? This belt is a bit longer and narrower, so I guess I will need to search around for a belt that fits those dimensions and fits higher in the groove. Thanks again.

[Joe L.]

Re: Need help with '66 L36 A/C pulley/belt application

Thanks much Joe, I saw your reply to an earlier similar thread, and seems you indicated it was discontinued in 1970? This belt is a bit longer and narrower, so I guess I will need to search around for a belt that fits those dimensions and fits higher in the groove. Thanks again.

Michael-----


GM #3889376 was discontinued in November, 1970 and replaced by GM #1490919. The latter was 15/32" X 45-1/2" but long-since GM-discontinued.

[Justin S.]

Re: Need help with '66 L36 A/C pulley/belt application

Tell them their gas tanks suck too. They're blissfully ignorant about the fitment issues

[Michael J.]

Re: Need help with '66 L36 A/C pulley/belt application

Thank you Joe, much appreciated. I think this is another case of the reproduction people being sloppy about their products on configurations, and focusing too much on cosmetics.

[Michael J.]

Re: Need help with '66 L36 A/C pulley/belt application

Tell them their gas tanks suck too. They're blissfully ignorant about the fitment issues

I have not tried those, but it is obvious they are using bad designs and dimensions too often, so I will not.

[Joe L.]

Re: Need help with '66 L36 A/C pulley/belt application

Tell them their gas tanks suck too. They're blissfully ignorant about the fitment issues

Justin------


Well, if you don't like the Quanta tanks, I don't think you'll like any other, either. As far as I know, the Quanta tanks are manufactured for them by Spectra Premium, a Canadian supplier of fuel tanks and other automotive parts. I believe that Spectra manufactures all of the Corvette fuel tanks on the market today regardless of brand or source. The difference with the Quanta tanks is that Spectra embosses the tanks they make for them with the O. L. Anderson logo which Quanta is licensed to use.

[Justin S.]

Re: Need help with '66 L36 A/C pulley/belt application

Joe,
I didn't know aboot that. Maybe Spectra is in cahoots with a strap manufacturer that will fit around their bloated tanks eh

[Michael J.]

Re: Need help with '66 L36 A/C pulley/belt application

Michael-----


GM #3889376 was discontinued in November, 1970 and replaced by GM #1490919. The latter was 15/32" X 45-1/2" but long-since GM-discontinued.

This one from Paragon seems to be more correct on dimensions than the Quanta one:

https://www.paragoncorvette.com/p-359622-air-compressor-belt.aspx

[Rick R.]

Re: Need help with '66 L36 A/C pulley/belt application

Michael, I had a similar problem with the Quanta alternator belt for my '67 L79 that I purchased through Zip. It worked, but was a tad too long, and put the alternator way out at the end of the adjustment slot. I know that I have all of the correct pulleys and brackets. I called Quanta directly and asked if they had a belt that was slightly shorter. Turns out their belt for a base 300 hp was a little shorter and it worked perfectly. Correct style and look, but of course the p/n on it is not correct for an L79.

Rick

[Mark E.]

Re: Need help with '66 L36 A/C pulley/belt application

Over the decades, I often experienced the "proper" sized belt was either too long or too short on many GM cars I maintained.

Manufacturing variance with the belt? Or stacking tolerance issue with the pulleys?

So I got into the habit of selecting the belt that actually fit that car. It's surprising how much difference 1/2" in length makes in adjustment. I like choosing a belt so the slot is 1/2" - 1" from its shortest adjustment.

Getting the exact right belt is even more critical for short balancer-to-water pump belts on some big blocks.

[Larry M.]

Re: Need help with '66 L36 A/C pulley/belt application

Michael:

When I purchased Quanta belts for my 1967 327/350 HP factory air car (no PS) years ago, neither belt fit as advertised. What I found on the AC belt was that there was one Quanta part number with a A suffix and another with a B suffix. The one I got with suffix A was too long and was returned. In talking with Quanta, they said a lot of guys found this belt too short, so they lengthened it for them, and gave it an A suffix. The B suffix belt was ultimately sent to me and fit fine.

I believe since my car is a small block, there were issues with the compressor clutch diameter, and some guys had the larger diameter (solid-lifter) compressor clutch. So the belt was too short for them.

Anyway, call Quanta and inquire. You might also consider buying a cheap 15/32 width hardware store belt that is about 50 inches long. Cut it and fit the cut belt to you car. Then measure the EXACT LENGTH of this belt that works for you and tell Quanta you need one that exact length. You should hopefully get a nice belt that fits your car, but the embossed part number may not be the one you want. I personally did this for both of my Quanta belts to finally get the ones that fit the car correctly (car had all the original GM pulleys by the way).

FWIW

Larry

[Michael J.]

Re: Need help with '66 L36 A/C pulley/belt application

Thanks Larry, yes I think Quanta just picked up the wrong specs. A friend sent me the AMA spec sheet, and it shows the wrong width (.38" instead of 15/32") and the wrong length (47" instead of the 45 1/2") compared to the original part referenced by Joe above. In measuring, the original size is dead nuts on, and even the '66 TIM&JG shows 15/32" for the width. But, I guess the reproduction business is very hurried and not much time to check correctness. At least Paragon has it right.

[Joe L.]

Re: Need help with '66 L36 A/C pulley/belt application

Thanks Larry, yes I think Quanta just picked up the wrong specs. A friend sent me the AMA spec sheet, and it shows the wrong width (.38" instead of 15/32") and the wrong length (47" instead of the 45 1/2") compared to the original part referenced by Joe above. In measuring, the original size is dead nuts on, and even the '66 TIM&JG shows 15/32" for the width. But, I guess the reproduction business is very hurried and not much time to check correctness. At least Paragon has it right.

Michael------


There are many errors in the AMA specs. One would think they would be always accurate but they are not. I think a lot of this has to do with "preliminary" information submitted by the various auto manufacturers to the AMA which got changed before PRODUCTION began.