Another quick question people, done a quick search but couldnt find much, took the head of my cvh of, as i got low compression on a cylinder, 1,2,3are 8 bar, cylinder 4 is 5 bar, started to smoke a little, so took head off and i poured some oil on top of the piston to test to see if the piston rings have gone,now i guess it shouldnt disappear, but how long would you give it before you say there okay? Cheers bill