fan belt question

[dave`12]

My engine comes from who knows what original vehicle. I've added aftermarket a/c and p/s. Because of this, when I bought fan belts, I had to measure rather give application. The only belts at the place I got them that were my length were notched, so I got them. 2 of the belts ride high, but I decided to try it out.

So, this morning, I go out to tinker and find that the alt belt has flipped around, with the notches facing away from the pulley! It was 2/3 on the pulley, which was still tight. One or 2 revs and it would have abandoned ship for sure. The engine had been ran for about an hour.

I have pictures of the engine after setting it up, and I know for sure that I put it on correctly. At first I thought someone was messing with me, but all my neighbors are cool, and being that I've been working on this project for a year now under a car port and have never had an issue, well I just don't think someone took tools, loosed it up, flipped it around, and put it back together.


So I need some opinions. Anyone ever hear about this happening? Some pics are below,
1st the alt pulley.
2nd the p/s pulley
3rd the crank, showing how they ride. The well seated belt is the a/c.

I'm guessing I should replace the alt belt, how about the p/s?

[truckster]

The belt on the alternator is definitely too wide. You need a narrower belt.

[storm9c1]

Believe it or not, belts do come in different widths. Belts should ride flush with the pulley. If they sink in too far, they are too narrow or worn out. If they ride above too much (as in your case), they are too wide and could sling off. You should be able to take your existing wide belt to a parts store and ask for a different width. You may want to get a few belts that are 1" longer and 1" shorter than your existing belt. The difference in width will also change the accessory tension profile (if you get the same length) and I'm not sure how much fudge factor you have in your accessories. So better to come home with 2 or 3 options and take the ones back you can't use.

The PS belt looks fine. It rides a little high but should be OK. The alt belt is the one that's concerning. If you can't get a correct width belt, the next option is to change the alt pulley.

[truckster]

Originally Posted by storm9c1

The PS belt looks fine. It rides a little high but should be OK. The alt belt is the one that's concerning. If you can't get a correct width belt, the next option is to change the alt pulley.

Except that the belt will still be too wide for the crank pulley. It's best to get the correct width. I believe the belt on mine was 7/16 wide.

[dave`12]

Thanx for the input. I got one 2 inches shorter and 7 16ths wide and it's perfect.

Still can't figure out how that thing got inverted and didn't come off...