Yeah, when I had The Beast in the dealer for the 150,000 mile service I had initially told them to just go ahead and replace the timing chain, and the service writer wanted to know why I wanted that done. He told me that if I wasn't having problems, leave it alone.

I lost the engine in my AMC (Renault) GTA at 105,000 when the timing belt broke on its interference engine.

My two current cars have timing chains, for that reason.

The idea being one space in the engine block and head can be shared so the block and head can be more compact = less weight = better MPG.

Timing belts falling apart don't get factored into the equation !

Pete.

I've only replaced two timing chains...one in the aforementioned Ford, and one on a '65 Plymouth I rebuilt...since I was that far into the engine anyway, I figured it would be a good idea.