5-Cylinder Timing Belt

["Dahl, Dave" <dad@roadnet.ups.com>]

     All this talk about pistons meeting valves reminded me that my timing 
     belt may be about due. I have an '87 VW Quantum Syncro (read: Audi 
     4000S Quattro) with the 2.2L 5-cylinder. I replaced the timing belt 
     around 60K miles and now have about 117K miles on the car. My 
     maintenance manual says absolutely *nothing* about replacing the belt! 
     I don't want to determine empirically whether I have an interference 
     or non-interference engine, so what is the collective net wisdom on 
     when I should replace the timing belt?  (BTW, I checked with the local 
     dealer.  He said to look at it every 15K, but I'd always heard that a 
     timing belt could fail when it looked perfectly good.)
     
     TIA.
     
     - Dave Dahl  (dad@roadnet.ups.com)
     - '87 VW Quantum Syncro
     - '93 Volvo 850 GLT