1996 GTS automatic belt tensioner pulley failure

[Ken Alker]

Has anyone heard of the automatic belt tensioner pulley failing on the Vipers? Mine is a 1996 GTS. Just after crossing the finish line of an autocross I heard my belt squealing. A fellow autocrosser brought a plastic ring to me that he said fell off my car after I crossed the finish line. It turns out it was the "front face" of the tensioner pulley! Upon investigation, it turns out that the outer portion of the pulley broke away from the inner bearing section and the bearing housing appears to have broken apart. Additionally, the front face of the pulley sheered completely off! It almost looks as if parts of the pulley melted, but it is hard to tell.

The only modification I've done in this area is replacement of the power steering pump pulley with the aluminum one made by Ipsco. I followed all directions and even changed the position of the power steering pump shaft to ensure the pulley was in line with the other pulleys (per Mark's instructions). My car delivers about 10% more horsepower than factory due to air box and exhaust modifications.

Perhaps this is a common failure similar to the plastic power steering pump pulley failure? Maybe the bearings just froze up and the belt spun the pulley hard enough to break it away from the bearing hub? Perhaps something else entirely is wrong and got the pulley so hot it failed? Is there any history on this subject someone could impart on me, or point me toward?

Thank you in advance.
Ken

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[Dan Cragin]

Its not a common failure, but the tensioner and belt should be replaced every 30k if you run your hard. You should replace the whole tensioner as sometimes they stick and cause excessive belt tension, loading that plastic pulley more. Your car is going on 18 years old, depending on your mileage there could be some other things that might need attention, like motor mounts, etc.

 

[Ken Alker]

Is there any merit to replacing the pulley with a billet aluminum version? Is that a bad idea for any reason? I do run the car pretty ******* the track.

 

[DrumrBoy]

No harm In going with the billet aluminum pulley. I'd also keep the spring-loaded tensioner unit In the trailer......I've gone through two of those on the track.....I think its a cast part and whether they get brittle with heat or are just not up to the task not sure, but they do break. Easy fix.....if you have an extra!

 

[Ken Alker]

Dan - is there a way to tell if mine is "sticking"? Is this something one call determine simply by pushing on it with the belt off (and if so, what am I looking for?), or is there no way to no if mine is sticking or not (resulting in assuming it is bad and replacing it blindly)?

 

[Ken Alker]

DrumrBoy - In what way does the unit fail? Does is literally break in half, or does it get a hairline crack, or otherwise? (Perhaps it is similar to the power steering pump bracket and pulley failure)?

 

[Dan Cragin]

If you pull up and down on the belt you will be able to feel if the tensioner is binding. I always just replace the complete tensioner assembly whenever I have an issue.

 

[Invasivore]

No harm In going with the billet aluminum pulley. I'd also keep the spring-loaded tensioner unit In the trailer......I've gone through two of those on the track.....I think its a cast part and whether they get brittle with heat or are just not up to the task not sure, but they do break. Easy fix.....if you have an extra!

Does anyone manufacture a aftermarket tensioner?

 

[Ken Alker]

I'd like to know if someone makes an after market tensioner as well. Mark Johnson of IPSCO in Colorado would be happy to make one. He has the capability and interest. He just needs someone to send him a tensioner so he can reverse engineer it. He already makes and sells the billet aluminum pulley to replace the plastic one.

 

[DrumrBoy]

I've broken two of them, mine have come apart at the mounting point, its a casting I think and a touch brittle. I just keep replacing with OEM; don't know of an aftermarket version. Sorry

 

[EllowViper]

I'm waiting to break mine at the most inconvienent moment...with the blower pulling so ******* the belt, I broke the front AC mounts. I just replaced my tensioner pulley since it was squeeking, but the tensioner was OK @ 55k miles. I did notice that the tensioner arm is pretty thin (all things considered). I would definately buy a billet one if IPSCO made it. One thing I did notice as I was re-engineering the front AC mounts. The belt (crank pulley) spins CW so as it travels past the tensioner, it is not under a lot of load like it would be if it was on the other side of the engine...thus why the tensioner is able to 'take up the slack' when you blip the throttle. The reason my front AC tabs broke is that the AC compressor is the first accessory that experiences tremendious belt tension as the engine spins...followed by the PS pump and then the water pump, and so forth as your move CCW. With the blower, most of the belt tension is experienced on the PS/AC compressor side of the engine. I guess that's why the PS pulley tends to frag.

 

[AZTVR]

For the price of an OEM replacement, it does seem like a good preventative maintenance item, esp on a 50k mile car like mine, and no labor charges. Hmmmmm......