420 SEL timing chain dilemma - Page 2 - PeachParts Mercedes-Benz Forum

david s poole · #16 01-14-2009, 10:33 AM

the 27mm socket is 1 1/16".

Randy · #17 01-16-2009, 10:58 AM

on my '86 420, I was scared to death that the engine might wreck after I bought it. It was in good condition otherwise, I had known the car since new, but it had 146,000 miles and 17 years. I studied this forum and manuals, then I went for it. first I measured chain stretch; found 7 degrees, about at the recommended limit. Then I went in; engine was very clean internally; the plastic chain guides were not cracked but were somewhat yellowed; replaced the upper guides, the tensioner (used an OEM as they were said to be better) and tensioner guide, and installed the new chain by seperating the old chain and connecting the new one to it and barred it through the engine. As these engines will bend the valves if you get the cams out of time, I removed all the rockers as a precautionary measure. I did not have any trouble and my car has run great ever since. I was glad it was in better condition than I expected, but I am also glad I went ahead and bought some anti-engine-wreck insurance. Caution: be sure you install the center link in the master link of the new chain; I almost left mine out by accident, and the result would have probably been a disaster. My car is a hobby mostly, not a daily driver, although it could be; I get satisfaction out of working on it. If you don't mind taking a chance, you have to decide that. I hope this helps and encourages you.