SERPENTINE BELTS KEEP SHREDDING

paddyrk

Member
Jun 7, 2018
71
4
18
Dublin, OH
Hi, I have a 1991 347 stroker that puts down 331 hp and 370 ft-lbs of torque at the wheels, and after I had it dynoed I keep shredding serpentine belts. I did an A/C delete about a week before the dyno day and it seemed to run fine, but the computer was so messed up that it hardly made any power anyway. I took it to cars and coffee in Columbus (a 20 minute highway drive) and ran in hard on the way there, and then when I did the same thing on my way home, about 10 minutes in, while just driving normally, my father who was behind me said he saw the belt fly off, my battery light came on, then my coolant temp shot way up. We went back and collected the belt and it was only half of the belt. I replaced it, went home, then took it out the next day. It was a Sunday morning so of course I pulled once of twice, and it seemed fine. I popped the hood that night and found that I was missing two of the ribs on the belt.

Would this be a pulley problem? Or do I need a heavy duty belt? Any would help would be appreciated. Thanks.
 
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Usually it's an alignment issue which can cause shredding of the belt. Did you install an A/C delete pulley, or the Ford M-8511-A50 kit that moves the PS pulley up? I'm assuming the pulley?

With the new belt on, can you verify alignment? Since the issue started after the a/c delete, I would imagine there's a slighty offset from either the A/C delete pulley to the PS pump, or to the tensioner.
 
Usually it's an alignment issue which can cause shredding of the belt. Did you install an A/C delete pulley, or the Ford M-8511-A50 kit that moves the PS pulley up? I'm assuming the pulley?

With the new belt on, can you verify alignment? Since the issue started after the a/c delete, I would imagine there's a slighty offset from either the A/C delete pulley to the PS pump, or to the tensioner.
I installed a delete pulley from LMR, I will check the alignment, I assume everything should be straight up and down?
 
Tell tail sign is if the front part of the belt is shredded pulley is too far back, if the back of the belt is shredded then it's to far forward, gives you an idea of what to look for when checking the alignment.
 
Is your idler pulley smooth...or does it have shoulders like this ?....

Screenshot_20181022-151726_Chrome.jpg


Or smooth like this....

Screenshot_20181022-151739_Chrome.jpg


The pulley should have shoulders like the original factory metal one. Under stress the tensioner will flex and cause the belt to throw... or shred.

The only local store that sells the correct one is AZ.... they have been selling people incorrect pulleys for 20 years and won't fix it.

Here's what the original looks like...top pic....

Screenshot_20181022-152246_Chrome.jpg


It's also highly likely that you have an alignment issue... but change the tensioner pulley if you have the smooth one also.
 
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I used washer between the pulley plate and the mounting plate and that was able to move it backwards enough to not have it rub against the front of the delete pulley. Now I’m off to terrorize super cars around the city.
 
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