Hey folks, I believe the timing chain stretches due to tensioner going bad and putting excessive pressure on it .. if you guys agree is there a way to preemptively swap them out and prevent the dreaded timing chain replacement job ? Atleast the one on rhe outside Maybe??

The chain stretches due to the constant load it's under pulling the cams/valvetrain and all that's attached to it. The tensioner is just there to keep the slack out of the "loose" side of the chain as it runs so it doesn't jump teeth.

Unfortunately, the chain is a maintenance item on these engines. It's not even that bad of a chain replacement.

That's what I thought Joe but few members here found that the tensioner over time extends to the max when compared to new one it was extending out quite more supposedly due to oil starvation or age and causing the chain to stretch out, I hope those guys can chime in

The only way to observe tensioner is visually and you need to remove a few pieces to view it. Usually if you invest in inspecting the tensioner you might as well check the chain slack and degree of tensioner protraction.

The tensioner goes out because the chain is stretched, not the other way around. The tensioner can stick in the extended position, yes, but it's not like the stretching of the chain will go away if you put a short tensioner back in.

We've measured the "chain stretch" using the MB tool on cars that have timing codes and extended crank issues, and even with it found in spec, a new chain solved the issue. I don't think inspections are 100% accurate on these engines unfortunately. We have two in the shop now that have cam timing codes/extended crank, no matter what we do it almost always comes down to being the chain.

Ugh I hate that job lol

Another question: When you put in the new chain do you rivet the last link or is there an easier way to do this ? I for the life of me keep thinking the last rivet will come off ?? I know its paranoia

you daisychain the new chain to the old chain and snake it in. pretty easy actually...

You mean all the posts on this and the diesel forum about elaborate efforts to replace the chain and tensioner are DIYs going WAY above and beyond? Can you do it without taking off the front of the engine? Or do still have to take off the front, but just to keep the timing straight you daisy chain it?

It can be done without removing all the front cover. That's why you feed the chain through.

dang it...

Has anyone heard of the timing chain jumping off its tracks? What causes this?