As title: any ideas as to why? This is on a 944 track day car. It uses a five run belt and so far its shredded two in two thousand miles. Everything is lined up correctly, there are no obvious marks on the drive pulley nor on the alternator pulley: and the belts were both from an oem manufacturer...

 

Not easy ....


Is it your car ? Can you show me photos ?

 

It is my car yes, but its difficult to see, let alone photograph. The first belt was fitted by an experience Porsche fitter and the replacement by an AA patrol, who left it slightly too slack. As over tension doesnt seem to be the issue then Im stumped.

 

Something is cutting the belt . Maybe a good idea to take the belt off and check the vee's for a rough edge's , I take it the belt has worn in the same place both times?

 

Does the pulley have flanges ? or is it a flat pulley like the subaru ones?

 

Its a five run belt and both belts have snapped and fallen off. There are no rough points that can be seen.

 

Kinda puzzled .

If it's not to tight and there is marks on the pulley the only other thing I can think of is heat causing it to snap ?

 

Mmmm, trackday car..... does it get over-revved much..... i saw a belt simply stretch due to the speed it was spinning at one day... just a thought.... if it is something like that, then i would suggest you tension the belts a bit more than just tight.....

 

No track use between the new belt being fitted and failing this afternoon.

 

sorry but i'm stumped ..


it is either


overtightened.

getting too hot - for some reason

has something on the crank or alternator pulley cutting into it



Well, thats what I can think off anyway , if anyone else has any other ideas for this chap



If anything needs to be done to the pulleys just give me a shout

 

bearing in an idler gone, transferring heat and vibration to the belt.

Simon

 

are the pulleys 100% inline ?
Any recent work done also?
Wonder whats been altered/adjusted/replaced that may have started the problem xxxx miles ago