How to check timing chain wear limits?

[tri again]

85 250 es.
2nd engine with the same issue, both new 2 me.

Occasional chain noise that goes away and is not consistent.

I pulled the tensioner and it was almost all the way extended.

The manual says to screw in the tensioner preload screw,
bolt it to the engine and then let go of the screw so the tensioner plunger
can push on the chain rail.
Seems like it's only got another 1/4" to go before it has no more throw.

My thought is however far out from the engine the tensioner sits, is how
much you have left but the manual says nothing about that.

Sure seems to be a great indicator on how stretched the chain is.

I may pop a couple more tomorrow on good running engines just to get a
general idea of chain health.

Any other ways to check a timing chain?
Do they get real noisy before they throw?
and what do they destroy when the do throw a chain, or do they just get sickeningly annoying
and we change them because we can't stand the noise anymore.

Get DID chains and guide rails and set aside 5-6 hrs to change each one?

Thanks

[kb0nly]

If the chain is rattling and your out of adjustment on the tensioner then its time for a new chain. I had a 250ES dragged to me about a year ago that the owner said it was rattling on the timing chain then it suddenly made some horrendous noises and died. The timing chain jumped off the camshaft sprocket and tore everything up. I had chunks of metal in the crankcase. I did manage to fix it all, took a lot of time and a lot of money, a new timing chain is a lot cheaper!

[tri again]

Thanks kb,
that's what I needed to hear.

Maybe finally build a garage and save these 2 projects for next winter.