AC compressor only powered by the crank pulley

[dexleo2]

Hello everyone,

I'm considering installing an aftermarket A/C in my 1973 Mach 1. I got to looking at my 351 Cleveland in my Mach 1 and my water pump pulley is a single belt groove and the crank pulley is triple grooved. So my power steering is around the crank and around the water pump, the alternator is direct to the crank pulley and so as it stands if I was to add an ac compressor I would only have the crank pulley to spin it. I'm wondering if I have the compressor hooked only to the crankshaft pulley will that work or will it spin it too fast, or do I need to search for a 3 groove pulley for the water pump. Thanks everyone.

 

[jmontes]

I installed a CCA kit in our 71. I didn't like the CCA Sanden compressor mount as it utilized a super long belt for the AC compressor and alternator on the 2nd grove of the crank pully. Ended up buying a Vintage Air compressor mount which works much better. It utilizes the front grove on the 3 grove crank pully with a 52" belt and works great. So to answer your question, yes you can use the 3rd (front) grove to drive the compressor.

https://www.vintageair.com/custom/product-pop.php?pn=131351

 

[Steve McMahan]

As I remember, the stock AC system used an idle pulley that was mounted to the frame that held the compressor. I’ve seen guys replace the stock tecumseh compressor with a modern one, and keep the original mount and idler pulley. Just another option to use the crank pulley.

 

[dexleo2]

My car don't have A/C, now so I don't have any of them parts.. Maybe I will see if I can find some maybe. Thank you

 

[Hemikiller]

Here' s a good pic of the stock AC front dress for the 302 and 351C. The AC tensioner pulley is missing, it attaches where the red line is. This gives you a good visual of the factory setup, which is only driven by the forward most groove on the crank pulley.

IMO, if your aftermarket setup can utilize factory brackets and pulleys, it'll be a much better setup than some of the aftermarket bracketry I've seen.

 

[Steve McMahan]

And another reason you might consider this, if you look closely at the brackets and pulley, the AC compressor’s crank pulley is a difference that the one that powers either the Alt or the PS pump. I suspect two reasons: 1 AC pump needs its own speed, 2 we tend to really tighten that belt, and it might put too much stress on the WP bearing. Just my 2 cents.

 

[dexleo2]

thanks everyone. I greatly appreciate the advice...

 

[Mister 4x4]

My car was also a No A/C car and I installed a Classic Auto Air system. The instructions said to run it off the power steering circuit, but I wasn't keen on that (3-pulleys for V-belts is the magic formula, I believe).

I picked up a factory idler arm kit and scored a 3-groove pulley from an A/C-equipped parts car, and also grabbed an adapter piece from Original Air (a co-company of CAA) to mate up the idler pulley bracketry and the newer Sanden compressor.

This isn't my engine, but hopefully it helps illustrate how the Sanden compressor and factory idler works together.

 

[Bobby]

I used a Classic Auto Air replacement system to replace the original stock system. The modern compressor used the original belt from the crank to the compressor and the manual tensioner pulley. It has the exact same configuration that yours has.