I was told by a MB club owner, member, Timing chains on early V8 should be changed every 100,000, however to check if the adjuster has been changed, take off the passenger side valve cover, you will see a hole in the head directly above the chain adjuster, run your finger through the oil on top of the adjuster, if the surface of the adjuster is a dirty brown its an original, if its white, its been changed. mine was white have 172 000 its starts in the winter at 10 below 0, hardly touch the key and all other times, the chain does not make a noise, a quiet motor and fast. most reliable car i have ever owned, 10 years this month.