Thick oil to solve valvetrain noise?

I've got a ticking coming from under the passenger side valve cover, I read that the first thing to try is a thicker oil, how thick would you go? is 20w-50 too thick? engine runs pretty well, maybe a slight occasional miss, haven't done a compression test yet. any thoughts? I'de love to just tear this engine apart and figure out what it may be but that becomes difficult since right now I rely on my Scamp to get me to work and school...
Thanks in advance!