Long ago in a Galaxy far, far away...

There was a company that made adjustable timing belt cam pulleys for the 1.3 engine.

You might find a mention of it either in really old (2002-2003) posts at the Geo Forum at Offroad.com (if they still go back that far...) or in the tech stuff at Izook.com (a fine leisure service of ZukiWorld.com!)

I hope that this helps!