Lower timing chain priming /firing method? aj16 engine

Hello
I am replacing my lower timing chain tensioner blade , however no matter what i do i can not get the piston to release far enough to take the slack of the lower chain , i know is gravity fed , I poured oil in there and tried to move the piston and still had no luck , any help will be appreciated , the car is a 1995 aj16 powered xjs ,i tought i will have better lock on x300 forums the reason i posted it here

Look here I think I remember Jim addressing this in his write up:

http://jimbutterworth.co.uk/8timingchains.htm