On a U.S. spec 1980 M117 450: I replaced the timing chain on this car about 120,000 miles ago, and now it’s time to do it again. Can 10 (crankshaft) degrees of retard on the passenger side camshaft be attributable to chain stretch only, or does it signify further problems such as worn out sprockets? Is it critical to replace the tensioner rail as well as the uppers? I am planning on running the new chain through, and need to go shopping…THANKS TO ALL!

I would always replace the upper sprockets with the chain. If the chain is worn, the sprockets have to be to. They may not fail, but they will wear the new chain faster.

Install new rails and a tensioner.

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Benzmac:
Donnie Drummonds
300E
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM
OWNER OF MB AUTOWERKS .COM

Can't help you out with the timing chain question, but the 450SLC 5.0 is one cool car. How do you like it?

JP Toronto

Awesome. Simply awesome. I am an SLC nut, having had 4 during the last 15 years. I currently have a 1980 US spec car (“the Slug”) and the 1978 5.0 (“the Rustbucket”). It is a totally different driving experience. It’s not just the 240 vs. 160 horses (1980 specs). It is also the 500+ pound difference. There is much less weight on the front end, so it turns in sharply, and the anti-squat rear geometry is nice. Mine has the rare (unheard of?) factory alloys in a TRX size – 390mm. LOVE IT LOVE IT LOVE IT!