Timing belt versus chain

[Victor Norman]

I recently did some engine work on a 1998 A4 1.8T. Now this car has both
a belt and a chain - the belt drives one camshaft and the chain connects
the second camshaft to the first. At 80000 miles the timing belt was
fine but the chain tensioner had completely worn away, to the point
where the engine lost all oil pressure (it's an hydraulic tensioner).
Result - one wrecked engine.