engine ticking sound?
 

The engine in my 1977 450SL recently developed a faint ticking sound under the right valve cover gasket over the rear cylinder on that bank. The camshafts, and valve seals were replaced within 30,000 miles ago. What is it? Lifters?

77 450SL
172,000 miles

Valves always make a slight ticking noise. When this ticking noise starts to get loud, then the valves are out of adjustment.