UncleMaz

Could not update title. I want interested parties to know. K050330 is too short! Broke my crank pulley clean off! Use the Gates K050335 instead. This is the next size longer. Thanks. More road/AX test updates to follow.
Original thread: https://rennlist.com/forums/924-931-944-951-968-forum/420972-bargain-early-ac-delete.html (post 11)

Rock

What the hell? Was the belt made of like steel?

If a belt broke a crank pulley... id suspect something else was going on.... but maybe im wrong?

UncleMaz

Could be, but just in case the belt was too tight, I wouldn't want someone else to have the same problem. Belt is fine, alternator spins noise free, oil pressure, but no crank pulley.

N/a 944

BELT BROKE YOUR CRANK PULLEY?!?@?! GOod god. That either saved you in a way, or the belt was made of steel!

UncleMaz

I went to the store to buy another 24mm socket, optimistically thinking I just need to retry the belt. So, I was surprised too. I heard clunking when it came off. I wasn't spinning the motor much more than 3500rpms at the time of failure. Without the evidence (I'll never find the pulley/pieces), it will be difficult to know for sure.

FRporscheman

Shoot, I even bought a 858mm belt and was about to put it on Wednesday. Guess I should find something new to do on Wednesday.

This thread is useless without pics.

genikz

Michael, I just yanked the crank pully off my spare block. You're more than welcome to it. I can express mail it if you need me to.

UncleMaz

858mm should be perfect. This one is/was 854mm. Where did you get the 858mm one? I think you would be fine with that one.

Chris, thanks for the offer. I am picking one up this morning. Michael

UncleMaz

I will take a picture of where my pulley used to be

Jfrahm

If you think about what a too-tight belt does, it puts a rotating bending force on the crank, pulleys and shafts. This is an excellent way to break something that is very strong, bend it back and forth 10,000 times and see what happens.

-Joel.

genikz

Very good point, Joel.

robert944h

Do you have any way to gauge the tension on the belt? The a/c belt by factory specs runs pretty darn tight. Your acually supposed to use the 9201 tool (same used on the timing belt). Set the belt to 9 on the gauge then one complete turn on the adjuster.

FRporscheman

I ordered a 6PK860 at work (I work at a bmw shop). (I dislike bmws). But the one we got was a 6pk858 but whatever, I'm gonna try it anyway.

But I was about to order it from here: http://catalog.autohausaz.com/autoha...product=5pk860

You can just do a part number search for whatever belt you want. The first number is # of ribs (some need 5 some need 6, check yo application). Then a PK. Then the lenght in mm. So my belt is a 6pk858 but on autohausaz they have 6pk860 instead. Other sizes I've checked are 872 and 875.

I wanted to do the 944spec alternator tensioner... and I think for that, a 858 belt will be too short, so I might try ordering a 872.

I first tried Kragen for the belt. They said they could order anything, but only had 840 and 880 in stock. If anyone needs exactly 858 and cannot find it anywhere, try a random mechanic shop, they deal directly with worldpac.

UncleMaz

FAILURE UPDATE

I would go down to take pictures, but I have had a long day.

I went down to Frank's this morning (see Where in the World thread). Turns out, the four 10mms were sheered off like this: 1) Clean full thread 2) Head sheered off (full fill) 3) One stripped out and remaining bolt half way down. 4) One with head and 1/3 bolt sheered off.

I will post a pic later.

It appears the heavy tension, combined with a jimmied crank pulley probably caused the failure (Frank's hypothesis). I am sure you could use any belt between 857-860mm and it would work perfectly. The belt I had on there was to tight at 854mm. Arash you are good with your belt. Should fit perfectly. I am now running a 863mm belt on there now with no problems but would prefer it a bit snugger.

UncleMaz

Thanks Arash. Michael