ticking sound gets louder with engine rev. using a stethoscope, i have isolated the location on cylinder 1 location. ticking sound gets very pronounced when stethoscope is placed on exhaust manifold on cylinder 1. rebuilt heads have 20K miles on them. chain is also new. what are the suspects in this case? lifter, valves, tensioner? thx

Usually ticking is a collapsed lifter....

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If it gets louder like that it could be something more serious. I have a collapsed lifter or two; the noise goes away when the oil pressure comes up, it's no big deal. His/her noise gets louder when revved, AND the noise originates near cylinder 1. Did you replace the tensioner with a NEW one when the chain was replaced?
I don't own a Mercedes V8, but I do know you MUST replace the tensioner along with the chain or you're asking for trouble. Some will say you must also replace all of the guides and rails as well while you're in there. It just makes sense. You don't mention replacing any of these. I'd be willing to bet the tensioner is not tensioning the chain and you need a new one, plus you need to replace the guides & rails. You should have done this while you were in there. Do it now; if that chain jumps a tooth the engine will be a paperweight and the scrapyard will be calling your name. Good Luck

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