1986 420SE V8 full emissions gear now 124K miles. Just read 500 posts on "Timing Chain Tensioner" but did not find a clear answer to my timing chain clacking noise. Clacking Noise goes away when car is idling; goes away when engine is revved. Clacking noise been there since I bought car at 93K miles and had just had right side cam replaced by a German indie. Clacking noise is getting louder now. Engine has factory compression, does not burn oil; very strong acceleration, smooth idle; no metal shavings in oil pan. Up front: new timing chain and rails; new timing chain tensioner installed about 10K miles ago to solve clacking noise with no success neither has the new timing chain and rails made the clacking noise go away. Air pump is disconnected. Cruise control unit is disconnected. I know there has to be a solution to this problem that does not require an engine tear down as some less than reputable Mercedes shops in my area have suggested (they can hear those $5,000 dollars ringing!).