I have heard that it is possible to check for chain stretch in these cars (420SELs - mine is an 86) by measuring how far off the cam timing is. How is this done? Is it hard, and can my mechanic do it quickly. I am curious because I know chains in these engines need to be replaced every 100,000 miles. I'm past 180,000 now, and although I have no record of a chain change in the records that came with the car I'm sure it must have been done. I am just wondering how much longer before I need to change it. Also, if the timing is retarded due to chain stretch, what kind of other benefits will I see, other than avoiding a major catastrophy (better mileage, more power?).

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Jason Priest
1999 E430
1995 E420 - retired
1986 420SEL - retired