Why am I shredding belts?

[lilmarauder]

I have gone through 2 belts on my cobra. 2.9 whipple, e85, all the goodies. I have read about factory tensioner issues, but cannot figure out why the car is literally turning the belt into a seven rib.

It will cut the front rib off of the belt and then it stops. It will continue to run and drive like normal, except the belt has sheared a rib. I am assuming it is my factory tensioner flexing allowing the front of the belt to ride on the edge of the pulley and it shears it off?

Anyone experience this? I'm kinda stumped

 

[1Fast-Turbo-Cou]

Check pulley alignment and make sure your idler pulleys don't wobble around.

 

[lilmarauder]

I should have mentioned I have dual bearing metco idlers everywhere but I will check them all.

I did notice that the belt rides normal on everything but the tensioner....once the belt is shredded it rides on the front of the tensioner pulley.

 

[lobra97]

try a torque wrench believe it 18-22. i kept busting inner belts and finally torqued them and luckily belt has been fine, staying in place likes its supposed to

 

[Woody6799]

I would say tensioner flex. I would look into upgrading your tensioner or adding the metco support brace.

 

[Zemedici]

Sounds like tensioner flex. But make sure the tensioner is torqued down as well

 

[lilmarauder]

try a torque wrench believe it 18-22. i kept busting inner belts and finally torqued them and luckily belt has been fine, staying in place likes its supposed to

Torque the tensioner bolts? If that's what you mean, I've got more than 18-22 on them

Seems like a thump tensioner is the way to go..

 

[cobra-k]

i had the exact same problem and i spent a while trying to figure it out by shimming pullys ect, it it ended up being the tensioner. for me i couldnt tell it was my tensioner until i decided to removed it. it was bent out of shape literally. it was so bad that the inside of the tensioner pully was grinding into my bridge plate. replaced the tensioner problem solved.

 

[lilmarauder]

I am going to install a thump tensioner and see what happens

Thanks for the input

 

[CobraBob]

Good advice posted in this thread. Good decision on your part. Post a follow-up post later so that anyone finding this thread in the future will know for sure how you made out. Great choice on the tensioner replacement; Thump tensioner is a good one!

 

[TXEnginerd]

Do you have an aftermarket alternator? That's another pulley to check...

 

[blknredsnake]

i was shredding and throwing belts every 50 miles, this was after an alternator swap, laser aligned and havent had a problems since, Unless something is bent or tensioner is bad, check alternator pulley

 

[lilmarauder]

Thanks for all of the help and suggestions. One thing I will do is post back with the outcome of the thump tensioner.

The things that changed was a 4lb metco crank kit, and a bigger alt pulley. All of my idlers are tight and roll very nice with a touch of resistance. The alt pulley seems to be tight and in place. If the tensioner doesn't solve the issue, the alternator is next.

I did put the factory tensioner in the vise and play with it for a few. It will flex inward (engine side). This could be the problem.

Thanks,
Chris

 

[lilmarauder]

The thump tensioner is on with the factory idler. I didn't think I would be too geeked about a tensioner....but man what an awesome piece. Super solid. It truly makes the factory tensioner look like junk. So far no issues with the new belt. I will post back when I really put the car through some hard pulls.

Chris

 

[lobra97]

nice! good to hear its on there nice and steady. yeah i tightened mine a lot and it was shredding belts like crazy. i actually went to 22lbs and it stopped doing that. these cars are very moody, good to hear yours is good though.

 

[lilmarauder]

Did a nice burnout and some decent pulls tonight and I have no issues now. I would say the thump tensioner fixed my issues.

 

[Stage 4.6]

I had the same exact issue as OP, started a thread a while back as many other people had the same issue. I never tried the RR tensioner, mine had the billet UPR tensioner, I purchased a brand new Stock tensioner with no fix to my problem, replaced all idlers with METCO DB, snub, brackets + shimmed alternator and no fix.

Finally broke down and purchased a new METCO 4lb crank pulley and hub and problem solved. The Hub on mine was about an 1/8in thicker, causing the belt to ride forward and strip exactly a rib of my belt.

 

[Woody6799]

Nice! Good to know. I plan on doing the thump tensioner but for now I just have the support brace. Hopefully I can swing it this winter when I do metco pulleys

 

[lilmarauder]

Just to reiterate, it's been a little bit now, and I have no more belt issues. Car holds boost longer as well. 100% of the issues were related to the factory tensioner.

 

[CobraBob]

Great that you took the time to post follow-up comments. Helps others in the future who might have this same issue. :thumbsup:

Really happy to hear that your belt issues are solved. Thump FTW! :rockon: