how often is a timing chain replaced ?
every 200,000kms or

its for a friends car

For most cars, generally every 100,000kms (major service).

__________________
"Wrong fitment".

Timing chains don't have an interval (replacement) period.

Unless it's an early 3 series BMW........

What car is it (just realised your not Spec IV darren!!) ?

Chain guides can be replaced if worn out as can the tensioner....but there only done if / when noisy.

__________________
[CENTER][SIGPIC][/SIGPIC][/CENTER]
[CENTER][COLOR=#ff0000]Built Ej207: Semi-closed RA Cases - Wiseco Forgies - Manley rods - BC 272 cams - GDA Heads - billet f/whl - Vi-pec - WbO2 - 800cc Yellow tops - TD05-20G - 409Hp ath @ 1.75bar on E85[/COLOR][/CENTER]

My mistake. I know that some cars have belts and some have chains, but i would have thought they would still have the same interval for changing/checking.

__________________
"Wrong fitment".

a chain is obviously more durable then a belt.

On the corrado/golf vr6s they usually get changed around 120.000 miles so around 200k....

If they aint making a rattling noise from cold or hot they are fine usually.....

its for a 180sx

Ahem....both the SR20 & the CA18 have timing BELTS not chains......

100,000km or 3 years which ever expires first.

__________________
[CENTER][SIGPIC][/SIGPIC][/CENTER]
[CENTER][COLOR=#ff0000]Built Ej207: Semi-closed RA Cases - Wiseco Forgies - Manley rods - BC 272 cams - GDA Heads - billet f/whl - Vi-pec - WbO2 - 800cc Yellow tops - TD05-20G - 409Hp ath @ 1.75bar on E85[/COLOR][/CENTER]

I have seen belts fail with minimal K's on them but they were around 5 years old, be aware that they fail in great fashion, even if you only have 20***k's on the odo, change it, it's a lot cheaper than valves, guides, gaskets, labour, head repair, etc etc.

I am guessing he is up around the 200***k mark??

Ahem.....Google FAIL Rossco.

SR20 has a chain.

I wouldn't change it unless it's rattling. Exceptions are V8 Mercedes with single row chain, change every 100,000. Gemini's (if there are any still on the road) Toyota 18R and Magnas that rattle for 300,000km and still never break.