low oil pressure

this is an add on from the last oil pressure problem......

i tryed the 20-50w and a new filter (not fram) and it seemed to solve my problem but, by running a heavyer weight oil i seem to have an engine knock, not severe but noticable..i think i will step back to 10-40w or maybe 10-30w in the hopes that i got a crappy oil filter..... but i wanted to get some imput from you guys to see what you think....so what do you think

Heavier oil usually reduces knock, rather than causing or increasing.

Can you describe the knock?

it soynds like valves.. i thought that it might go away if it got warmer but no luck