Aftermarket Belt Tensioner Pulley Failure
 

A couple of years ago my tensioner went bad and I rebuilt it using a combination of stuff including some L98 parts and an aftermarket aluminum pulley from UPR products (the pulley specs as a 85-93 Mustang ultra light tension/idler pulley). I followed the tensioner rebuild project of the Forum, so if you have this pulley I suggest you check it.

I can't think of any reason other than poor build quality as the cause, there are actually several holes although you can only see the one in the pic. The belt shows some damage too, I was noticing some odd coolant temp and voltage fluctuations which is why I started poking around. Guess I'll go back to the factory pulley.

http://www.zr1.net/forum/picture.php...pictureid=3973

Re: Pulley Failure
 

Pulley bearing failure?

H
:cheers:

Re: Pulley Failure
 

Possibly... I have been noticing a silvery oily residue under the air horn and around the general vicinity of the belt. Although I think that is from a leak in the A/C system which is another area I need to address and that could also account for belt slippage.

Re: Pulley Failure
 

Judging from the hole in the pulley (which is aluminum) looks like it froze and the belt wore a hole in it, might be the source of your silvery residue?
H
:cheers:

Re: Pulley Failure
 

Hmmm, that's a good possibility

Re: Pulley Failure
 

Yup. Beat me to it!! That's the pulley seizing up.

Bob: I replaced mine with a GM pulley for a C4 LT1. Works now for over 10 years! Also, Jerry's Gaskets has ZR-1 pulleys.

Re: Pulley Failure
 

After looking closely at the photo appears it could have started as fatigue crack.
Is the center section of the pulley solid or spoked?



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Re: Pulley Failure
 

Pretty sure Jim Voter had that exact same pulley fail on the way home from BG

Pulley Failure
 

It’s hard to imagine that billet aluminum is weaker than plastic (stock) and I agree it has to be bearing failure with a seize that heated and burned by the belt friction. It would seem that would be noticeable though. I’m tempted to go back to stock myself. I guess another reminder to make America great again and we need better quality parts overall and stop outsourcing if this is from China.

I can’t remember the Dynomite post. Was it bigger and needed and larger belt too? If same sized belt used it could cause more tension on the pulley than it should have? Thanks for sharing since some of us did this mod.


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Re: Pulley Failure
 

One of the symptoms I had was periodic low voltage at idle. Sometimes I'd be sitting at a red light and the voltage would drop down to like 8-9 and the stereo would shut down. It was an intermittent issue and my thought was this was due to belt slippage, possibly from my leaky A/C system. I had my alternator rebuilt a while back and that made no difference so I eliminated that as the possible source. Now I'm thinking maybe it was the pulley occasionally seizing up and dragging down the belt speed at idle. Guess we'll see once I get that replaced.