Timing Chain Stretch and replacement
 

MB does not state if timing chain stetches X degrees then timing chain should be replaced, it does say about the use off offset woodruff keys for compenstation, how much would it take to stretch before ultimately jumping teeth(disaster). I read some posts as little as 5 degrees and others that say the chain will outlast the engine if oil is changed every 3,000 miles. So what is the answer??

Chaosmosis
'73 MB 450SL

Timing Chain Stretch and replacement
 

I don't know about other models but the early 380SL (81-83) are the ones with the weak chain unless they were upgraded to a double roller. I believe all 450s have double roller chains. Mine is a single in a 1981 and I changed it at approx. 85K and am ready to replace it again at 151K. Important as well is the tensioner. Before replacing mine the first time I could hear the chain rattling at start up because the tensioner was weak. I was lucky I did not have a major failure.

This may ease your mind a bit but my knowledge is limited so don't rely soley on my reply.

hi

do a search on timing chain and look for the thread by thomas pindelski. thomas did an excellent picture tutorial on this subject. he estimates based on certain factors when he'll replace his. just seek this out he even has a website he allows you to look at for all his maint work.
good luck
craig

Thanks, Craig!
 

My reasoning (illustrated and explained on my site) attempts to separate chain wear from tensioner and guide rail wear.

I replace the tensioner first and then look at the change in chain 'stretch'.

On my 560SEL only the tensioner had to be changed (see the chain rails page) whereas on the 380SLC both the tensioner and chain (twin row) needed replacement (see the chain replacement piece).