Adonay

I have now broken this F"#¤ thing 3 times . Could sombody give me any sugestions to why ? Alternator is to blame we belive.

This was a brand new piece .



I have also broken the one for the power steering 2 times . Engine was rebuilt\refreshed this winter and mainpully was changed as well as crank .

I really had it with this problem . Does not help that i noticed clutch slip yesterday either .

DLS

Sorry for Off topic but do you hang on 944sverige.com?
do you have more pictures of the engine or any movies of it?

Adonay

Not at all.
I have a profile on 944sverige.com "joacim951" i will make a build thread there later this year when i actually get to install most of the upgrades i have for the car. Maybe il make a 3l pictorial as well. I have some videos of the car not sure i want to put those on the web. Maybe if i go back to nurburgring again i can post something useful \ interesting.


Love your tripple steam vent btw

ramius665

I've seen a few tensioners break, but they're usually the original and were improperly adjusted. Hopefully a new alternator will fix things?

DDP

I've never broken one of these. If you've broken both sides I would say you're over-tightening them. I'm not sure but why would both break? The only common ground there is you tightening them. Different parts of the engine. It might help to loosen the alternator bolts a little to allow it to move more freely.

lee101315

Maybe the belt is too long? Or are the balance shafts out of phase?

DDP

If there belt were too long the threaded part of the tensioner would simply come out while being extended.

Did these break while driving or while installing? I guess I assumed during installation before.

Ronin-951

Check the Main Crank Pulley for cracks and the Alt. pivot and Bearings for slop. Inline Compression loading on the adjuster is out of wack somewhere.

Adonay

Balance shaft are 100% correct . They are NOT to tight . I have used both loose and tight. More loose to allow the altenator som "free play" that snapped even quicker. My mechanic have never seen this before and he has long experience with these cars. Belt is the correct porsche part supplied by lindsey.

This is while driving usually at woot or engine brake.

DDP

Yeah, with what you just said and the way it broke, I agree with Ronin.

Techno Duck

Ive seen this happen with the PS tensioner due to the pulley wobbling on the crank (wasnt centered right). But if i remember right the alternator pulley is bolted to the balance shaft gear i think? Might want to check and see the pulleys all align correctly.

Scott H

This thread popped into my head while I was reading through the Porsche manual. I'm pretty sure the turnbuckles need to be mounted in front of the mount, not the rear. If I had to guess there is a slight angle to the turnbuckle, then add a little torque and vibration and voila, crack. The manual doesn't explicitly state this, but assembly is pictured with the turnbuckles in front, Crazy Eddie posts a good picture in this thread: https://rennlist.com/forums/944-turb...-question.html

If nothing else, something to try with the next one?

Richgreenster

Stop 4 wheeling you car!

JK

The broken piece looks to be out of alignment to the other atachment point. Maybe the bolt is being torqued with side load then with the vibration it just snaps.

Adonay

.. i think it will be fine this time around.





This time around i am sure it will hold if it does not i will trade it for the mechanics 930

JohnKoaWood

2 most common issues I have found on the number of cars I have been working on...

1) over tightening the jam nuts... they only need to be snug, not squeak tight...
2) over tightening the mounting hardware... if the mounting bolts are too tight, the ends will distort when you adjust the tensioner... causing them to break... (have seen a few looking like the pictures you posted... each one had the moutning bolts WAY too tight, and MOST also had the jam nuts WAY too tight)

next time, loosen the mount bolts before you adjust the adjuster... then snug them once the belt is tensioned.