Hi, welcome to Just Answer.
Valve timing has a large difference from every engine and make to make. Typically German mechanical engineering was advanced for it's time and so this intricate valve and camshaft setup is still used from the 300E to the late models. Also, such perfection on the valve timming has also evolved all accross many European, Domenstic and Japanesse imports. On your model the camshafts need to be PERFECTLY timed, using the marks below...and the #1 piston on TDC (Top Dead Center)
Illustration of 3.0L 300E (most common)
Lead Technician
A.S.E. Master Technician, Advanced Level, Smog - European, Domestic, & Asian -- Car Category Mentor
Thanks for the NEGATIVE feedback...your question was "Is there big difference in Valve Timing on Mercedes 300E 6 Cyl engine to American engines." And that is the answer I provided, no where in there did you say "you must fix my car." Negative feedback affects my ratings greatly, and it's not fair I receive it for the mood your in becuase you can't fix your car or ask the appropiate question to get the help your looking for. I went above an beyond your question to provide a suitable answer, and if you needed more help all you need to do is ask, just like the BIG red words at the bottom of the post.
Listen, I'd like to help out, that's why I'm stuck to this site all day - trying to help someone who is stuck. But, as with all sites, negative feedback should be reserved for when someone has not only been unable to help, but may have given you a completely wrong answer. I thought you were just asking for the difference between cam timing of different makes...I had no idea you had noisy valves. I wish there was a way the feedback could be reveresed...but anyways...let me know the answers to the questions below and I can tell you why they are making that nosie.
Rip
After you installed the camshaft, and had it torqued down, how long BEFORE the engine was actually started? Hours, days?
And did you use assembly lube or grease on the valve stems and the followers, as well as the cam lobes?
Perfect...than you have no problems...and you havn't made any mistakes. The noise you here is normal during the first startup of the engine after reassembly, and it should lessen the more the engine runs. At about 10-15 minutes of running and at normal enigne operating temperature...turn the enigne off, wait about 30 minutes and than let it run again, there shouldn't be an more valve noise.