Originally Posted By: JOD
Originally Posted By: edhackett
Come on Bluestream, get with the program. Timing chains don't get longer as their pins and bushings wear. Engines shrink.
Motorcycle frames get shorter too. I don't know how many times I have had to put on a shorter chain to keep one in adjustment.
Ed
first off, comparing a motorcycle chain to a completely sealed engine is, in a word, ridiculous. Yes, chains "elongate" from bushing wear--but they don't "stretch". And the mechanism of elongation is important, since a timing chain operating in a completely sealed environment will see a fraction of the elongation that a motorcycle chain will see, given that it's exposed. It's not even close to being the same thing...
Generally, the tensioner in almost are cars is enough to account for the very minimal elongation the chain will see during the duty cycle of the engine, as long as the chain is seeing adequate lubrication. And overwhelmingly, if the timing system in a chain-drive engine has advanced to the point where it's causing issues, it's almost always wear from the chain guides causing the issue, not chain elongation. Chains to not "stretch", unless metals have some unique properties I don't know about...
An "elongated" chain is known as a "stretched" chain. Chain wear can be caused by numerous factors. When they elongate they are considered stretched and when too far elongated/stretched they are no good and have to be replaced guides and chain