Weird belt problem
 

A few times I've noticed that the blades on my alternator have bent out and began to fray the belt. Ive especially noticed it after spirited high rpm driving. Then today I noticed to my shock that the belt was down to four ribs and a alternator fan blade had broken off! I checked the bolts on the alternator and they are tight. what would cause this? Belt tensioner bad?

Re: Weird belt problem
 

If it is a tensioner I wrote a article in the Heart Of the Beast publication (Relief for a Tension Headache) to rebuild your tensioner. If you go to the main website and log in and then go to the Members Only section and then Newsletter and select issue 34 and Page 28. Hope that helps

Dave Hetrick

Re: Weird belt problem
 

Did you replace your alternator & replace the pulley with the one from your original alternator?

Re: Weird belt problem
 

And did you use the spacer. If you replaced the blades with no spacer this will happen

Re: Weird belt problem
 

I have not replaced the alternator. It is the one that was in the car when I got it in December. However I do not see a spacer between the pulley and the fan.

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Re: Weird belt problem
 

You would need to remove the pulley to see the spacer, if it is there (image below shows the "stack"). As you suspect, if the spacer is missing, the Original pulley will press against the fan when the shaft nut is tightened. As the fan warps from the pressure & heat cycles, the pulley can also slip on the shaft under charging load, compounding the problem.


http://cdn3.bigcommerce.com/s-nkg90o...0.1280.jpg?c=2

Re: Weird belt problem
 

When I had a similar problem, my fan blades were hitting the alternator housing in different spots., they were not forcing the blades out. And it was making quite a racket. I tried bending the blades out myself to eliminate the noise. Little success for a very short time. And that was with a factory pulley. That's when I figured out that the replacement alternator did not have the factory spacer, it didn't have any spacer at all. My lack of the spacer did not cause the belt to fray in anyway. Not saying this could not be the cause, just from my experience on my engine.
When you use a replacement alternator, just make sure you use your original pulley and spacer as mentioned, (that's if they are still on the vehicle, which in your case they may not be) and you won't have any problems.
Just thinking out loud, IMO, your alternator fan blades would have to be so out of round and distorted to cause a blade to break and the belt to fray. I would tend to agree with Dave, that it may be the belt tensioner that could be causing this type of problem, to where higher or even normal rpm operation would be causing the belt to be interfering with something that would cause it to fray.
It would be interesting to see what your alternator fan blade looks like, post some pics if you can....
And was or is your alternator charging properly during this time???

Re: Weird belt problem
 

Try to identify the belt and see if it is the correct length.

Re: Weird belt problem
 

I got the pulley off today. The spacer is there so I'm at a loss for an explanation now. Belt is also the correct length.

Re: Weird belt problem
 

Can you provide pics of the alternator, pulley, fan and spacer?

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