I am having a problem with keeping my belt onto the water-pump on my 396. The belt keeps poping off. I tried a smaller belt, it squeeled and burned off. A larger belt simply flies off.

My water pump and pullies are not seized as I can spin them by hand. So I know this must be an alignment problem between the belts. Question is, how exactly do you get this dead on?

Thanks for your help!

DV8R - I'm experiencing a similar problem. My belt comes off at higher RPMS. I've noticed that the belt is making contact with the front edge of the water pump pulley. I've order some water pump pulley shims and see if I can somewhat center the belt on the pulley.
By the way I'm using a six rib pulley setup off of a late model Chevy truck.

DVR8:
I presume you are running a stock style V-belt set-up.

First, the inside diameter of the belt must never ride on the pulley - only the "V" sides of the belt should touch the sides of the pulley. The belt should be mostly inside the pulley groove, but a small amount above is tolerable typically.

Assuming the pulleys are not bent (you would see them wobble at idle): What I do is get a straight edge and check to see if one of the pulleys is off canter. All should be pretty close. The problem I have seen usually is with the alternator, and shimming the alternator brackets with some thin washers does the trick.

If the mis-alignment is real bad, you can sometimes tell by standing beside the car and looking along the belts (like you would check a 2x4 for straightness).

Good luck.

If I remember right, there were two different sets of pulleys for the big block motors. One was the standard pulley and the other was a deep groove pulley. I think the deep groove pulley was used on high performance motors to combat with the higher rpm's and more wobble with the belts at a higher speed. Also, have you checked the tightness of your belts after you installed them and ran them? I had a problem once with my 69 Charger where I installed a new belt, ran it for a while, never rechecked it, and while driving on a highway one day out on a cruise, i noticed my temp starting to go up. Pulled over to the side of the road and all of my belts were off and gone. graemlins/clonk.gif Always check the tightness after you run it for a while so they have a chance to wear in then recheck them to make sure they are tight enough not to fly off like mine did. graemlins/sad.gif graemlins/clonk.gif Hope this helps.

I had a similar problem, and tried just about everything, and yes, all the pullies were lined up. What happens is that the belt "rides up" in the alternator pulley. Now bear with me here, I'm an old fart and new to the computer stuff, so posting a photo ain't gonna make it (I even tried to e-mail you a diagram the other day and that didn't work either).

Started with a piece of 3/4" by 1/8" flat stock, bent it 90 dgrees and welded it to the lower alternator bracket. Welded to the top of that, is another piece of the same stock about 2" long positioned parallel to the underside of the belt, with about 1/8" clearance between the flat stock and the belt. You want to get this thing as close to the pulley as you can, but leave enough room so you can change the belt if needed. Finally, the leading edge of the stock is slightly bent downward and smoothed out so that it won't fray the belt if the belt "flaps".

This instantly cured my problem. Other guys have gone to boneyards and picked up old idler pullies.
Either way, whatever works. graemlins/thumbsup.gif