Belt slip... please help, oh wise gurus

At the same time I installed the new 396 I went to a 2.75" "UltraGrip" pulley. I had major belt slip and it shredded the belt (it's a pretty aggressive pulley, so if it slips, I'd expect that).

I replaced that with a 2.65" plain Vortech pulley, which is slipping even more. In fact, even with no boost at 3500rpm you can hear it start to squeal.

With the old motor and a 3.1" pulley I had some slip until I went to a shorter belt (in fact a little too short), which produced wonderful boost.

This is a Vette that has a sucky 6-rib setup, so I may just be doomed, but I'm at the point of running a bolt through a bracket to force the tensioner in the direction of applying more force.

Before I do anything rash, is there a checklist of things I should look at other than:

- Belt and pulleys clean and dry
- Apparently in alignment with each other as best I can tell

Thanks for any advice...

- Dave

I wonder if they make a SD spring loaded tensioner pulley for your car, that would solve your problem!

Originally posted by SMOKNZ
I wonder if they make a SD spring loaded tensioner pulley for your car, that would solve your problem!

Isn't the Vortech tensioner already spring loaded? Also I thought Scott only sold tensioners for ATI's.

Originally posted by davepl
At the same time I installed the new 396 I went to a 2.75" "UltraGrip" pulley. I had major belt slip and it shredded the belt (it's a pretty aggressive pulley, so if it slips, I'd expect that).

I replaced that with a 2.65" plain Vortech pulley, which is slipping even more. In fact, even with no boost at 3500rpm you can hear it start to squeal.

With the old motor and a 3.1" pulley I had some slip until I went to a shorter belt (in fact a little too short), which produced wonderful boost.

This is a Vette that has a sucky 6-rib setup, so I may just be doomed, but I'm at the point of running a bolt through a bracket to force the tensioner in the direction of applying more force.

Before I do anything rash, is there a checklist of things I should look at other than:

- Belt and pulleys clean and dry
- Apparently in alignment with each other as best I can tell

Thanks for any advice...

- Dave


You are going to think i am crazy but on my powerdyne set up (which is also a 6 rib pulley) I Sprayed belt dress to keep the belt from slipping with out haveing to crank down the pressure on the tensioner.. Once sprayed it created a real sticky surface for the pulley to grip ....

Double check to ensure that all of the pullies are aligned properly. I was having the same problem you are until I swapped to the ultra-grip (which I believe is the same maker as yours) RR. I found that pulley alignment was the real issue.

Double and triple check those pullies for alignment issues.

Tim

convert to an 8rib. I just ordered my 8rib kit for my vette from ASP

I'm not in the mood to wait around 12 weeks, especially in the summer! Maybe this winter...

I just made a crazy mod to my tensioner, will let you know how it works!

Originally posted by IDOXLR8
Isn't the Vortech tensioner already spring loaded? Also I thought Scott only sold tensioners for ATI's.

Whoops (insert foot into mouth)

I didn't know the Vortech's already had a spring tensioner, sorry :D