Does anyone have experience running an alternator, water pump, and Sanden-style A/C compressor all with a single v-belt? If so, how long has the belt lasted?

This is how my Crestline came to me. Seems like a single belt would not be up to the task of running all 3 for very long.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

My Classic Air A/C on my 55 bird is set up as a 1 belt. It’s been on several years with no problems. It works as far as the belt goes, and with the electric fans, fuel pump, EFI, and electrical wipers I went to a 90 amp alternator. With everything on, including the headlights and blower fan, it holds the output voltage and the belt doesn’t slip. In retrospect, I’d have bought something with a 3 belt set up. It’s a bitch to change the belt because there’s very limited movement between the big alternator, block, and frame.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

In my opinion a single belt would not be a normal set up unless the alternator and AC compressor would be on opposite sides of your engine. Normal belt contact with a pulley should be over 90* if possible. Without PS I would use 1 belt for each item. My 56 Victoria with Vintage Air AC engine brackets has the Sanden AC compressor where the generator was stock and the alternator in front of the right cylinder head and each has its own belt. Only the water pump pulley has approximately 90* of belt contact; all the others are way more. I have PS on a 3rd front pulley. All belts are relatively short which will be better for longevity. I don’t believe I’ll ever need to change one but they are easy to remove one at a time over the fan which has a shroud. I requested a VA engine bracket kit to hide the compressor.
This is my experience and others may differ and it only to share what has and is working for me on a Y-block powered factory car. In the distant past AC compressors had 2 belts and wrapped almost 180* of pulley contact. Newer compressors don’t seem to need as much. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.

Thank you for the replies.

I found some installation instructions for the A/C system that came with the car. Instructions and components appear generic so I am not sure where the kit came from. It specifically stated that the belt should be installed around the generator, compressor, and water pump, just like it is.

I have always seen multiple belts on factory a/c installations. The belts only ever drive 2 accessories. But, like DryLakes said, the modern compressors don’t require as much power to run.

My installation runs smooth and quiet, cools well and doesn’t seem to slip, so I guess it’ll work, especially if it’s held up for years for others. Just wasn’t sure how much tension/load a single belt can take. I’ll be sure to carry a spare and some changing tools.

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

It sounds like your belt system is almost a square/rectangle which means all the pulleys are seeing 90* of contact with the belt. Since PS is normally the one that slips your sounds good to go. If your alternator is in front of the right cylinder head with the compressor under I would just check every so often on the voltage from the alternator.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

That’s right, it’s a square. The alternator is under the compressor, both on passenger side of engine. There is some voltage drop at slow hot idle with the compressor on, but it comes right up as soon as I accelerate at all. I’m not gonna worry about it, just cruise and see how it goes this summer!

1954 Crestline Victoria 312 4-bbl, 3-speed overdrive

Carry an extra belt and stop worrying about it. 

The '57 Tbird I just got has been mostly sitting since a  Classic Auto Air system was installed on it about 12 years ago.  Now, in getting around to checking it out, it will run for about a minute, cold temps on the outlet hose, and then the single belt system will begin slipping.  Not sure if drag increases on the pulley from the compressor, too lose a belt, not enough belt coverage, or oil/ freon needed. 
Just sharing my experience to date. 
Ralph   

rponfick..check the belt in the pulley grooves along with your other inspections. You don’t want the belt on the bottom of any of them, they need the side grip. Remember also the more tension you need is harder on the water pump bearings and the front alternator bearing.. 

56 Vic, B'Ville 200 MPH Club Member, So Cal.