I'd think 20w50 is way too thick for your engine. I'd go 10w30 or 10w40 in the summer, 5w30 in the winter. Unless you have VERY badly worn rings or leaks and are trying to limit oil consumption, 10w30/40 is the best for your engine in the summer.

Ticking is usually caused by sticky hydro lifters/studs. Thicker oil makes them stick more.