I've got the crank at TDC and the cam gears are lined up.
But when i advance the distributor all the way, the crank still doesn't reach the 16º mark.
It goes to about 13º

How do i fix this????

i've got a b16

 

Have you done any work around the cams or timing belt recently? Are you absolutely sure the cams and crank pulley are lined up correctly? How are you getting your timing readings? Is the engine idling normally at ~800RPM? Are you sure your timing light is in good working order?