Timing belt

["Jerry FIELDS" <Jerry.Fields@ccmail.adp.wisc.edu>]

     Sean Reifschneider writes:
     
     "My big question is:  Is the engine free wheeling?  If the belt 
     "breaks, will it crash the valves?  I'm guessing it will, so I'm 
     "planing on at least inspecting the belt in a couple of weeks when I'm 
     "back home."
     
     I have had 2 timing belts break, one on a Ford product, the other on a 
     Toyota. Maybe I was lucky, but did not trash the valves or head in 
     either case. Toyota occured at highway speed 55 - 60, Ford was on a 
     city street at 30 - 35. Both engines were 4 cylinder overhead cam 
     designs with 4 or 5 speed manual transmissions. 
     
     When you check your belt, check the camshaft and crankshaft gears for 
     wear. I replaced both items on the Ford, the Toyota looked good, so I 
     left them alone. Both engines also had an idler pully for correct belt 
     tension. (I've not done this on an Audi, so cannot speak from 
     experience.) Check this idler, and if you install a new belt, make 
     sure the tension is at the recommended specification! It is a good 
     idea the check it even if you don't change the belt...
     
     FYI the Toyota had 215K on it when the belt let go. I am the original 
     owner, so can verify the mileage! The Ford had, I think, around 90K. 
     
     Hope this helps.
     
     Jerry Fields