Weird belt problem

[ALLTHECAMS]

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?

[mgbrv8]

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?


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

[A26B]

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?

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

[GOLDCYLON]

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

[ALLTHECAMS]

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.

Sent from my XT1080 using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[A26B]

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.

Sent from my XT1080 using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

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/products/665/images/2191/ZR-1_OriginalAltPulleySchematic__89295.1496501998.128 0.1280.jpg?c=2

[Roadster]

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???

[XfireZ51]

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

[ALLTHECAMS]

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.

[Roadster]

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

Sent from my SM-G935P using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[GOLDCYLON]

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

Sent from my SM-G935P using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

I was going to ask that next. GC

[ALLTHECAMS]

I'll try to get that tomorrow

Sent from my XT1080 using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[ALLTHECAMS]

https://uploads.tapatalk-cdn.com/20170610/215366ff5b6abd72afe14c247930c662.jpg
https://uploads.tapatalk-cdn.com/20170610/e24591b988bfce155a7c2617ca781e0f.jpg
https://uploads.tapatalk-cdn.com/20170610/8472ddfde65bae518e8baff8882b8032.jpg
https://uploads.tapatalk-cdn.com/20170610/7737ba3a135ea5865eecec23a5b61433.jpg

Sent from my XT1080 using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[ALLTHECAMS]

I got a new alternator fan today, about a 1/4 inch smaller. Put it all back together and took it for a test drive. Seems to be working so far.

Sent from my XT1080 using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[ALLTHECAMS]

https://uploads.tapatalk-cdn.com/20170610/87cd836ad17b0f631c45fc3ad090c2f7.jpg

Sent from my XT1080 using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[Roadster]

Everything appears to look normal, except.....the fan...wow, did that get chewed up!!! I have never seen an alternator fan do that.
And the back of the pulley seems to have a weird shaped wear pattern, where the finish is worn off more on the bottom LS of the pulley in the pic. Maybe nothing at all, but just seems odd.
JMO, the only thing that I can think of, is that you have a bad bearing in the alternator, or maybe the tensioner is at fault as it was mentioned earlier. Therefore causing a wobbling effect that would have created your problem.
again, just thinking out loud!!!
I thought that the fans were originally black, your appears to be silver (the one that got all chewed up). Not that it means anything.
But there has to be something somewhere, somehow that caused the fan to look like that!!!
Good luck, hope the new blade works out for you, I would just keep checking everything after every outing to make sure it is ok...


A side note, the only other thing I could think of is, if the fan was hitting the outside housing of the alternator on a continual basis for a long period of time, then that would most likely chew or break off a piece of the blade as shown. But then you would also have major wear marks on the alternator housing. Just another thought!!!