low compression on rebuild engine any help?

I have recently rebuilt a rodeo 2.6l 4ze1 engine new pistons, rings, bearings, seals, even a rebuilt head. and befor i put new head on i was getting 60 on #1 60#2 30#3 120#4 now with new head installed i have 120#1 90#2 60#3 60#4. any help. could i have timing set wrong on camshaft. every time i have taken head off and put in back on i have came up with diffrent on the cylinders. what is the mark on the side of the cam sprocket adapter. i go by the mark on sprocket but i have been told that it is out of time causing the vavles to be out of time.. any help.. Thanks in advance