Chrysler Repair: Timing Belt, piston head, dodge shadow

Question
In one of your replies to a question of mine, you mentioned that if the timing belt broke in my car, (1994 Dodge Shadow ES, 3.0 V-6)that the engine would not be damaged.  How is that possible?  I read somewhere that there are two types of engines, but I forgot the names of them.

Thanks

-K

Answer
Hi Kevin,
The terms are "interference" and "non-interference"  and refer to whether the valves occupy the same place as the piston at any point in the cycle of the engine. If they do, and the timing belt breaks then there will be one or more valves that are open when the belt breaks and thus are struck by a piston and damage results, or if they are never in the space travelled by the pistons then the valves cannot be struck by the pistons when the timing belt breaks and no harm can be done.
According to the '94 manual for the 3.0L engine, "the piston head with valve recesses, along with the cylinder head, forms a compact spherical head with clearance for total valve lift with pistons at top dead center."  "Clearance" means "non-interferance".
Let me know if something happened to your engine if its belt broke.
Roland