Q. 1 - Figuring out what V-belt I need?

[Machinos]

Two questions/posts at once!

First thing I need to do is get this alternator running. I've never had to fit a v-belt before, and I have no idea what the best way to do it is... it's a Delco/GM alternator and the pulley groove looks the same as the crank pulley on my Chrysler, so I think that should be fine. But I dunno what size belt to get. My guess is that I could figure out out with math by measuring the pulley diameters and the distance between the centers, but that'd be a bit of a hassle since the fan is between them. If I went to NAPA would they let me try a few different ones so I don't need to guess?

[Deyomatic]

One way that I've done it is to take a length of rope, the kind that won't stretch, and wrap it around once to see the size of the loop you'll need, if you choke the alternator as close as it will go to the water pump pulley, you can just add a little bit to make sure you can still get it over the pulley when installing. If that makes sense.
I still needed two trips to find the right one. When you find it, save your part numbers and write which belt it is and put it with the car's registration paperwork.

[36-3window]

put the alt midway in it's slotted adjustment.

take your tape measure and go all the way around the pulleys you want the belt for......go down to Napa a buy a belt that size....and one a liitle smaller...and one bigger....KEEP YOUR RECEIPT.....see what fits , you may have to go back for a different size...take back the ones you don't need


keep in mind that not every size in lenght is available

[BigJim394]

If you have or can get an old long belt that fits the pulleys correctly, put the alternator at the mid point of the adjustment range. Cut the old fan belt and fit it around the pulleys and trim one end so the ends butt up against each other when you pull them tight (as best you can). You can then take the belt out and duct tape the ends together or put a small hole in each end and wire the ends together. Then, if you have a parts store that has been around for 30 or more years, go there, and they will have a gauge that they will put your belt on, that will tell them which belt you need. I don't think Autozone will have a belt gauge.

[old beet]

Hey, if this don"t fit, can I get Anotherone?.....OLDBEET

[SwitchBlade327]

use a rope like mentioned above and make it fit as tight as you want the belt & tie it so it's the size of the belt you need. take it to advnce and they should have a tool that they can put it on and it'll tell them what size you need. We've got one at the store I work at, and that's how people around here figure it out.

[disastron13]

Go out to your shop and look in the Machinery's Handbook, there's an easy chart- just measure between the centers and look it up. It shows the right length for different diameters etc

[Machinos]

Thanks for the tips everyone. After I read everything it did occur to me that it doesn't need to be nearly exact, no one's even gonna see it. I just took a sewing tape measure and went around the pulleys, gonna get a belt tonight and see if it works.

[1oldtimer]

also most older gm alts take a 15 series belt. which is skinnier the the 17 series.