My '78 with a ZZ-4 GMPP engine loses the AC belt every other time I get over 5200 RPM. Of course it takes the power steeering belt out with it and sometimes the alternator belt along too.... Overheating time!!!

Any suggestions out there???

Dave

Check alignment, tension, and condition of the A/C clutch. If the belt has been over-tensioned it could have broken cords which will cause the belt to walk off. You should be okay at that rpm, but going to a mono-belt system might be better over the long run.

I assume it's only slinging the belt while the A/C is on?
This is why Duntov didn't want A/C on any of the solid lifter engines. It would always sling the A/C belt off at rpms over 5000. In 72, for the LT-1, they made the pulley with a deeper groove to keep the belt on.
Is your belt too wide to fit in the groove properly?
The A/C belt, since it's so long, has a tendency to "flop" at higher rpms, also. This contributes to the problem. Most of the belts today are very flexible(rubbery), making it even worse.
If the pulleys are all lined up right, and all of the brackets are tight, I would suggest trying a belt with a slightly narrower section width, so that it fits down into the pulley a little deeper.

Joel,

It doesn't care whether the AC is on or off, and the belt is the correct width. You gave me the "key" though........ When I pulled the non-matching L-82 engine out and dropped it in my '38 Pontiac, I remember the L-82 water pump pulley would not line up with my ZZ-4 crank pulleys and the 'Vette motor had deeper grooves than the chrome pulley I put on the ZZ-4. I now know what the problem is, just gotta figger out how to fix it.

Thanks for the info, big help!!

Dave

Hope that fixes it!!

Maybe cause the ZZ-4 might have the long water pump? Someone told me at a car show one time that big blocks have the deep grooves and will work, if it is the short-long pump that is causing the alignment problem maybe check on a long BB pulley, can't remember if he said that you might have to change the crank pulley also.

It's a short nose water pump and the pulleys line up just right. I afraid I gotta get a whole new set of pulleys. Might just look in to the serpentine belt trick..

Dave

Well depending if they line up or not there are pulley shim kits out there.  I know we sell some in the weiand line for shimming the water pump pulleys outward for better alignment.

Come to think about it that might just be one of my problems too.....

As I recall I used washers under the water pump pulley to space it out about 1/8" and it wobbles slightly, about .062" runout. Is there a website that refers me to the shims??

You are in Portland, I am in Nashville..., temporarily in Panama City now, Who is "we"???

Dave

We is Weiand, I work for them or Holley.

You may be able to find these or something similar to them at a napa, auto zone or Advanced.  High end speed shops would have these or probably even summit.  Problem with mail order is you end up paying as much in shipping as you do for the part itself.

Here is what they look like.

http://www.holley.com/products.asp?product=8230