I bought a 1990 Talon Tsi AWD for $700 bucks and after further investigation (and running it several times) and hearing horrible "clacking" sounds (heard here: www.zero2blur.com/clacking.WMV), I came to the conclusion that the car was driven with "out of phase" balance shafts for maybe 7000-10,000 miles. Here is what happens when you do that. (at least that is my theory as to what happened to this car).

This is the "belt guide" that sits behind the CS sprocket and in front of the front balance shaft.


This is the gear for the front balance shaft drive, the wear matches perfectly with the belt guide.


and finally the Crankshaft. Notice the worn away key, caused by the sprocket slamming into the crankshaft key because (I believe) the balance shafts were working together rather than against each other...

The guy who owned it before me spent about $1700 bucks in two trips to the same shop. The first time they did new intake valves, the second time they did the timing belt, and thats when the screwed up the balance shafts. The owner must have felt some strange vibrations going on, but just ignored it and kept driving until the "clacking" started.

Luckily I can remove the worthless balance shafts and save this motor...

Damn, I should be on CSI!