Fan belt on 68 C-20 no accessories

[Happy_dan]

Another of those really simple questions for things I should probably know.

I have a 68 C-20 with not accessories. Just the fan and alternator.

I replaced the belt and it seems to fit in the pulley quite well, but if I am sitting still and push the throttle by hand quickly, I get a squeal.

It's not the water pump since I out in a brand new one when I rebuilt the engine.

Does anyone have the part number for the right belt just so I am sure I have the right belt?

I believe what I have on there is a 15530.

[Willys_MB]

Is your alternator tight? If it's not tight enough it could loosen up enough to let the belt loose. You could also go to NAPA/O'Reilly and get a belt that's 1/2" shorter. You're currently running a 53" belt, so maybe try a 52.5" belt. Without pictures it's really hard to help figure this out. If you can post some pics of your setup we might be able to help you out.

Belts suck. They're just the sort of thing you have to trial and error. You can get a ballpark figure using a string, but you still need to get a belt and put it on there to really know.

[Happy_dan]

I will get pictures. The alternator is tight and the belt is tight.

I did a search and found several threads in the subject.

After seeing some pictures, I am thinking the belt might be slightly wide so it doesn't sit down in the groove far enough. It's really not a huge problem since it's only when idling and I snap the throttle. IN normal driving I don't hear it.

DISLCAIMER: I am hard of hearing and unless it's loud or I have my hearing aids on, I might not hear it even if it's there.

[Happy_dan]

Here are some pictures. I am not sure but it almost looks like the alternator may be ever so slightly off from the fan pulley.

[mr.mud1]

Originally Posted by Happy_dan

Here are some pictures. I am not sure but it almost looks like the alternator may be ever so slightly off from the fan pulley.

Hi Dan,Great talking with you this evening.i think you may be right unless it's the picture,it does look as if the alternator is back a touch?obviously you re-used all your original bracketry?try the old belt back on,when you have time and see if it's any happier?

[Happy_dan]

Yessir, all original brackets. I will look to see if I saved the old belt.
Maybe a washer or two on the alternator bolts.

[sick472]

It looks like you have plenty of room to get a straight edge in there. Place it firmly up against the faces of the pullies so that it is trying to touch the rim in two places on each, preferably as close to the center as possible (it won't be close, but at least not on the outer portion of the rim). If it's perfect...it will touch both pullies in two places, it not, you've got some adjusting/shimming to do.

My 85 K20 would squall at the shift point from 1st to 2nd. The pullies were out of alignment due to a broken AC compressor bracket. The alignment was off visibly at 3 feet away with the naked eyed. Once aligned and tightened with a 1/2" of belt slop using my thumb to apply about 10-15 pounds of pressure...squall gone.

[Happy_dan]

This is great. Thank you. I will get a straight edge and check as soon as I can

[Happy_dan]

Checked with a straight edge and all 4 points touch. Seems like alignment is ok.
I will take the belt back off and make sure the pulleys are clean look good.

If I can find the old belt, I'll try that too.

If you look at the first two pictures what I notice is that the belt sits pretty far down in the alternator pulley but almost flush with top of the fan pulley. Not sure if that is an issue, just an observation.

[sick472]

The depth that the belts sit down into the pulleys does not concern me, they look normal. I have had freshly painted pulleys squeal right out of the gate. Paint can be more slick than raw steel. I tend to sand the overspray out of the grooves when putting together a freshly painted pulley. A few motors that I have had really like the belts to be tighter than I'd expect, but once tightened down...no squealing. I often use a piece of broom stick to to get leverage on the alternator when tightening the belt.

[Happy_dan]

Thank you. I will get the belt off and clean the pulleys good. There could very well be overspray on one or more of them.