Originally Posted By: crw
I think you have your perspective backward... engines used to have chains but now many smaller engines use belts.
Rather the opposite. Many manufacturers are switching to (or in some cases back to) timing chains. Examples are many, including GM's Ecotec motors, Ford's Duratec motors, the Chrysler/Mitsu/Hyundai World Engine, VW's TSI motor, Toyota's 1ZZ & 2ZZ engine familys, and the Mazda engine in question. Timing chains are, undoubtedly, in vogue.
Originally Posted By: crw
Not to change the subject, but I wonder if anyone has produced a database that lists every engine and whether or not it has a chain or belt, and if it is an interference engine or not. I'd like to put all cars that have belts and are interference engines on my "cars to avoid" list.
I wholeheartedly agree, as I (by some miracle) avoided bent valves and piston damage when the belt on the AEG in my Beetle let go. Overall, though, it's more difficult to achieve a non-interference design with today's higher compression NA engines necessitating tighter piston-to-valve clearances (better quench) and higher lift camshafts. If you throw variable valve lift, duration, and cam phasing into the mix things get even tighter. A failure in any one of these systems, to say nothing of the chain/belt, causes catastrophic engine damage at worst, and expensive and labor intensive rebuilding and machine operations at best. Avoiding these technological advancements will soon become nigh impossible as they are adopted industry wide. The question is, is it better to have a more efficient and powerful engine, or one that won't self destruct in the event of a failure in one of these systems?
