engine knocking sound

Belches out exhaust smoke from valve cover breather and oil dipstick tube. Exhaust is not black or white. I finally did a compression test this weekend. Cyl: 1 - 180 2 - 160 3 - 160 4 - 185 5 - 185 6 - 170 7 - 160 8 - 170 The engine has slight knocking sound on start up, idles smoothly when...