Cam belt damaged - Help

[awmw]

I have a 1998 Audi A4 TDI 110bhp - AFN

While doing some routine maintanance I took the top cam belt cover off just to inspect the belt, not expecting to fing anything wrong but saw a lot of dust and fibres. The belt was not running in the middle of the sprockets but was off to one side towards the engine. So much so that it was rubbiing on the back plate and the side of the tensioner wheel was cuting into it.

The car has been running perfectly, not making any strange noises and I had replaced the cam belt, tensioner and idler just 5 months and 5000 miles ago.

I have taken the belt and tensioner off but can see nothing wrong!

I put a straight edge across the sprockets and tensioner and they are inline.

In these two photos you can see how the side of the tensioner was cutting into the belt and the markings on the belt surface. ( top of belt was the side close to the engine )

This photo shows how the belt was running on the tensioner. ( off to the left )

Here you can see where the belt has been rubbing on the back plate between the cam and IP sprockets.


I can't see anything wrong but don't want to put it back together with a new belt just to have the same thing happen again.

Anybody got ant ideas?

 

[marms]

Looks to me like the tensioner or relay roller is not sitting square. Did you clean all the surfaces when you changed them? You can often end up with traces of old lock-tight compounds etc and these can very fractionally affect the alignment and it only takes a very very small variance to cause the belt to drift in/outwards. Certainly not worth putting it back as it is.

The only other thing I can think of is poor quality parts? Did you use the OEM kit?