250 sx timing chain tensioner Q?

[tri again]

Still stuck on this intermittent T chain noise. 85 250sx.

Low hour machine.

I pulled the timing chain tensioner and it looks like it only has
another 1/4" of throw.

In other words, total throw is a couple fat inches and when I put it in against the
chain rail, it stands off about 1/4 inch.
Then you screw in the tensioner so the body will seat to the engine,
tighten it down and let go of the screwdriver and the tensioner pops out
to put pressure on the chainrail.

It goes out and stays there like most other tensioners but the chain will be quiet for
a few minutes and then clatters for a minute or so and then quiet again
for 20-30 seconds.

Valves are set at .003".

Manual only states to check tensioner for wear and replace as necessary but it would sure be nice
if they said something about how far out it should be for normal limits.

Seems like with a fat 3 inch overall throw, it should have more than the last 1/4 - 1/3 inch left.

Almost completely positive it's never been apart since I got it from
family friend who's grandparents never really used it much since new.

Overall pristine machine and hate to throw a timing chain for no good reason.

Any way to check stuff without complete teardown?

Thanks