How expensive is a new timing chain (and supporting equipment if necessary)? If it lasts twice as long as a belt but costs twice as much, it's not much of a gain of anything besides convenience.
(I'm not saying it's twice as expensive per km, I'm asking. I genuinely don't know).
Think of the timing chain as part of the inside of an engine, bathed and cooled by engine oil. As long as you keep up with oil changes and general maintenance, they should in fact last the lifetime of the engine. The timing belts are parts outside the engine and have an expiration date, thus must be replaced, in some interference engines, if it breaks, you now have severe engine damage. Non-interference engines, at the very minimum, you may end up just stranded. Hopefully, not your aging parents or children at night. Even if it the belt by a miracle does not break, you can bet the belt has stretched and cause the engine to run rough. Some people may claim it only cost so much little for their 626 timing belt. Hogwash.....There are bearings in the idler and tensioners, and water pump, those do not last a lifetime, they fail for obvious reasons. And there are the Crankshaft, camshaft and oil pump seals that are made of rubber that become hard and shrink and leak. By not replacing the idlers, water pump, and oil seals you run the high risk of premature timing belt failure. Idler bearings will seize and break you new timing belt, water coolant and oil leaks will contaminate the timing belt and, well, break the timing belt. Bottom line, who needs the added expense, being stranded, and possible engine damage done by a broken timing belt.
Yup, idlers, water pump, and seals need to be replaced, but not every 100k like you claim. And no, not all t-belts cost $1000 to swap out. The 3.5 in my Honda cost $350 (no idler, tensioner, or water pump, not necessary at 100k). I really don't see t-belts as a deal breaker at all. Ya, I would prefer a chain, but having a t-belt is not going to factor into my decision.
Sorry, but you must be a mechanic that's looking for work. How can anybody argue that bearings in the idlers and water pump, and critical oil seals do not wear out and should not be changed at 100K miles. Wow, oil seals are made of rubber that gets exposed to 190 degree heat.....Open up any auto repair manuel and read it, find out for yourself. Depending on the car, for OEM parts, you will spend $400-600 in parts and labor $400-600.
Here's the highly likely above scenarios for the Honda (interference engine?), replace the timing belt and labor and nothing else. 30-50K miles later, 1)water pump fails, owner could not see the leaking pump since it is inside the timing belt cover. Overheated engine, blown head gaskets, $2K to repair. 2)oil seals fail, contaminate timing belt, belt prematurely breaks, back to square one, replace belt and seals, interference engine, $2K. Seized idler bearings, timing belt breaks, back to square one, everyone get the picture.
TIMING BELTS = DEAL BREAKER.
