[skraeling]

Only ONE timing chain? You're rolling the dice ...

Wonder if Toyotas are as sensitive to the timing chain issue as the Hondas? I have a '97 Geo Prizm (Toyota Corolla) with 92K and thinking maybe I should have it done.

[bvw]

Here's one site that gives timing belt advice:
http://www.theautoshop.com/timing.html

[bvw]

I've had two timing belts (or chains) go on me. One an early 80's Honda I had let go too long, and another on a Old's Cutlass. Got both enegines rebuilt After rebuild and tweaking (considerable playing around with the early vintage electronic oxygenation controls controls) the Cutlass was hot. Leaf u-joint risking hot. Taking it home from the garage, some gent in a Ford Bronco plowed into it whilst I was at a stoplight and pushed it into a Septa Bus. The bus had an side panel and bracket damaged -- the bus shop bent the bracket out and replaced the panel from junker stock. Cost $75.

My hot Cutlass was totaled. I replaced it with an 1989 Acura.

[TalBlack]

There is a difference between a timing CHAIN and a timing BELT. Belts have to be replaced at about 60k.

Since way back when the Japs use a timeing chain tensioner to take up the dangerous slack that age imparts to the chain. THAT is one BIG reason that the jap cars last so damn long. The timing mechanisim is an engines weak link. The better it is the longer the car lasts. Witness the Mopar slant six which used GEARS.

[XBob]

on timing belts/chains

It has to do with engine design, and valve timing and belt/chain mfg type.

Put simply, follow the manufacturers recommendations.

There are several types of engines, and generally, engines with steel timing "chains" are more reliable, more noisy, and less stressed. Basically the chains never need replaced, until you go in for an engine rebuild. Timing chains almost never break and engines with timing 'chains' generally have a longer stroke and are 'undersquare', so there is no damage if the chain breaks, other than the chain.

Those with rubber timing "belts", which are basically fancy rubber fan belts. They get old, wear out and break. They also generally squeeze more performance out of a smaller engine and are quieter. But many have (if I remember correctly) an 'over square' design, where if the belt breaks, the valves are down, and they literally chew up the whole engine - just throw it away and put in a whole new engine.

So basically, if you are driving more than 60k miles on a timing 'belt', pray before you start it up, each time.