chain stretch?

[Padrino]

Has anyone ever found a chain that has stretched??

I have on tensioner piston that has extended further out than the other by quiet a bit, almost to the point that the chain is touching the case. The other tensioner/chain looks fine.

[Padrino]

bump

[CHILI]

Yes, they do stretch. I asked this question a while back and then PM'd Johhny Walker. He said the rule of thumb is, if you can get the tip of your finger in-between the chain and the case (at the tensioner sproket) you are ok. If it gets to be about 1/8" or less, it's time to change the chain. But, he also said (as did my mechanic) that it's VERY rare for a 911 timing chain to break. Normally it's the tensioners that fail and cause the big $ damage.

[Padrino]

thank you, thank you.

I get a sound like a bunch of marbles in the chain locker after the car has been driven for a hour or so, meaning the chain has warmed up and losened. I've dreaded that the only thing it could be is the chain sprocket on the intermediate shaft which my local mech thinks it is because there's a bit of slack in the when you grab the fan belt and give it a yank...the chains don't move but the crank pully moves ever so slight.

I'm just about to go through an engine rebuild to get to the intermediate shaft even though I have an even 180 lbs on each cylinder.

I think I'll replace the chains first and see.

[Doug Zielke]

Chains don't "stretch". Stretch implies elasticity.
Actually, the bushings and pins comprising each link, wear.
The accumulated wear elongates the chain.
If you have a lot of slack in a chain, it is just worn out, not stretched.

[yelcab1]

Originally posted by Doug Zielke
Chains don't "stretch". Stretch implies elasticity.
Actually, the bushings and pins comprising each link, wear.
The accumulated wear elongates the chain.
If you have a lot of slack in a chain, it is just worn out, not stretched.

IT is just semantic with the same effects.