Recently I had to replace the valve cover gasket and at the same time took a look at restoring valve lash to factory spec of 0.012 for exhaust and 0.008 for intake. Most of the clearances needed to be increased a mil or two and the result was an engine that ticks quite a bit more loudly. When looking into this, actually reducing valve lash seems to have a positive effect on engine wear, fuel economy and also noise produced. As a result, I plan to go back in and change the clearances to 0.011 and 0.007 respectively. In this round of maintenance, it occurred to me I have a chance of inspecting the timing chain. At what point does the chain or anything related to it need service? Is there a way of visually inspecting its condition?

 

An irregular rattle at idle that improves as rpm's are raised is one clue. the other is if a plastic timing chain guide is broken. The one single reason why I favor plastic guides over metal.

 

Forgot to mention this 2.4L '94 22re is approaching 250,000 miles and ask at what point timing chains are usually replaced?

 

250k is a lot. But the question might be what was the mileage it was last replaced.
But hard to say mileage-wise. Proper oil changing with a decent filter with anti-drain back does prolong their life.
But one thing we saw often was headgaskets and timing chains having fairly similar lives. This is one of the reasons I encourage people to remove the head when doing a timing chain. It’s not hardly anymore labor, you can do a MUCH better job, and you don’t have to fret about the headgasket going out in the next year.

 

I doubt the head gasket has ever been replaced / I am the second owner since 130k. I would rather not get into servicing the chain / head gasket, but would like to preempt any damage due to chain failure.

 

servicing the head gasket and timing chain on the 22re is cake. i do it in my driveway. takes the good part of about 5.5 hrs to complete the job, but i've done it a few times.

jimkola is right, at 250k, if neither has been changed, you should at least be considering it. the 22re is an interference motor, but when the chain breaks, it doesn't always result in piston & valve contact. however, because it can have that happen, better to replace it prior to breakage.

 

At 250k and 30 years I'd expect both the chain and headgasket having been done at least once. But if not, I can't imagine a better promo for factory parts.