This is what happened on may way home!

[kamaro]

I was on my way back home today, and about 500 yards away at a traffic light idling, I saw the charge light came on, I thought maybe I lost a belt, no big deal. But when I reached home and pop up the bonnet, this is what I saw :




That was a URO brand pulley with less than 600 miles on it. I guess I need to buy myself a genuine Porsche now!. And in case if you wonder, no, the belt was not over-tightened, actually it was a little on the loose side.

[stownsen914]

Yikes. Luckily no serious damage hopefully. Is/was the nut still tight? Sometimes a loose pulley half can round out the mount/boss on the fan where the pulley half mounts.

[pmax]

I’ll guess it’s China made junk failing from metal fatigue.
I would buy a used pulley.

Check the hoses for any damage from the shrapnel.

[kach22i]

Originally Posted by kamaro

That was a URO brand pulley with less than 600 miles on it............................

Thank you for the FYI.

Yikes!

[LIRS6]

wow that is impressive (in terms of its destruction)

Jason

[ahh911]

Are/were your alternator bearings good?

Phil

[pmax]

The belt's a keeper.

[2.7RS]

The tightness of the belt has to do with the number of washers.

If you didn't torque the nut properly it could be your fault.

And no. I don't work for URO. I'm an engineer

[walt]

Did you check the belt tension after driving a few miles. I have found that belt can become extremely tight after run-in.

I suspect something else is going on other than a defective part.

[LIRS6]

Curious - looks like 5-6 shims on outside, none on inside... ??? I don't see an a/c belt - is it possible that u had the belt on the a/c pulley which placed torque on the fan pulley?

Jason

[UROParts]

Hi guys, excellent questions and discussion, thanks to everyone for sharing your expertise - please continue.

We've sold about a thousand of pulley half 930 106 209 02 over the last few years without any issues, but just to be safe we're having Engineering grab a few from stock to analyze the metal and compare current production to the original pulley.

[Walt Fricke]

What is the yellowish color due to? Is that rust of some sort? Quatar a salt laden environment?

You can play failure analysis engineer here. Fatigue fractures usually start at a point, and spread. When the crack has spread far enough, the rest of the structure fails all at once. The original crack area often looks polished (from rubbing before the failure) and often discolored (water got in, so some rust on the crack face). In bolts, you can see a sort of beach sand ripple from waves effect, fanning out from the origin. And the final fracture area looks nubbly, a sort of fine sand stone finish, as it all broke at once, and had no chance to get polished. Here you have lots of places to look, and a much more complex shape than a bolt. But you might be able to spot some.

What is that cone shaped nut?

This does seem like a somewhat rare occurrence. The most common pulley half issue is one where the shim formula was ignored, the cup washer bent or otherwise wasn't able to clamp everything together, and the pulley half worked back and forth against the squared off part of the alternator pulley side where they mate, until a circumferential groove was sawn into that locking part, leaving the outer half free to rotate. Those outer halves, however, haven't themselves looked like they had failed or were ready to fail. Do your fan side pulley locking protrusions look like they are developing a slot?

[proporsche]

Originally Posted by kamaro

I was on my way back home today, and about 500 yards away at a traffic light idling, I saw the charge light came on, I thought maybe I lost a belt, no big deal. But when I reached home and pop up the bonnet, this is what I saw :




That was a URO brand pulley with less than 600 miles on it. I guess I need to buy myself a genuine Porsche now!. And in case if you wonder, no, the belt was not over-tightened, actually it was a little on the loose side.

i am sure you did nothing wrong..but why are all your adjusting shims on the outside of the pulley with only 600 miles on pulley how old is the belt? Plus you said it was loose a little?
Also i would send the pulley to the Euro guys in Simi Valley for inspection..

Ivan

[Geneman]

check out the serpentine belt conversion kit from clewett. i had a huge problem of belts jumping off ( is 911 RSR racecar). this solved it complety when nothing else would.. easy to install and uber beefy.
https://www.clewett.com/index.php?main_page=index&cPath=60

[UROParts]

@Kamaro, any chance you could post a photo of the pulley hub still bolted to the cooling fan?

Originally Posted by Walt Fricke

What is the yellowish color due to?

The plating is a gold color, see more photos on Pelican's site: https://www.pelicanparts.com/More_Info/93010620902.htm?pn=930-106-209-02-M253

[MBAtarga]

Originally Posted by Walt Fricke

What is that cone shaped nut?

Yes- good question from Walt - cone shaped nut or what? - and where are the shims located with respect to the remaining portion of the pulley?

[smadsen]

If the belt were riding properly in its groove shouldn't the fan side of the belt groove have a shiny mark where the belt rode? Hard to tell from the pic.

[kamaro]

It has 5 shims on the outside and 2 in the inside, its hard to see it in the photo but this is what I found when I took the nut off. The plastic cone is just a cover, it's a factory part I believe.

The belt was new 600 miles ago, and I had zero issues all the past time, no squeels or any abnormal noises, the alternator charged good, no overheat issues. and even when it broke it was so silent that I never thought something broke.

Its a bit hard to send the broken part back to URO due to my location, but I'm willing to send them any details they may need to improve their product. I'm not here to bash them, as I used several of their parts with no issues in the past, including a windshield seal that fitted better than the OEM.

[Cory M]

Never seen this failure before, then I see it twice in one day. Same thing happened to the 911SC taking on the Dakar rally right now:

https://www.instagram.com/p/CJmBPzWD6qG/?igshid=19yj6nof7xcda

[unclebilly]

Is it a European belt (slightly narrower) or a off the shelf b profile belt from NAPA?

How far did you say you drove like this? How many minutes?