[punk-coder]

My '94 Saturn had a timing chain instead of a belt, which was awesome until the chain broke. Due to it being metal it shattered and fused itself in various parts of my engine, destroying the whole thing. Instead of having to pay for a new timing belt, I paid $2,500 for a new engine.

[Tiksi]

It's usually not much better if a timing belt snaps either. Two valves can't occupy the same space at the same time, so often you get shattered metal everywhere anyways. The difference is that timing chain failures are rare, timing belt failures are expected.

[kagamine]

The country I live in owners change the timing belt before recommended date or else they pretty much can't sell the car for the price they want. It's a bid deal. So much so, that when I sold a car last year I was getting somewhat irritated by the question of it having been done or not (said so in the ad, tyre kickers don't know what else to ask about).

[colhom]

It's actually a valve and a piston you have to worry about. At normal engine speeds the valves will simply snap shut if the cam stops spinning.

Valves slapping piston is generally only a worry with an interference engine design.[1]

1. https://en.m.wikipedia.org/wiki/Interference_engine

[Tiksi]

Yeah, I was thinking of interference engines, especially OHC/OHV Interference designs. "Timing belt failure" is deeply anchored to Honda engines in my mind, which are pretty much all interference.

[Infernal]

My '08 Honda Fit may be interference, but it also has a timing chain that /should/ require no maintenance for the life of the car.