16 valves bend
 

what are the possiblitlies to bend all 16 valves
if all 16 valves are bend, most likely the head or even the block have problems right?
since i recently purchased an engine. and found out it has 0 compression in all 4 cyclinders after all the swapping work.
did a leakdown test. found out the head is leaking air...

if the belt is broken or put on wrong that can happen, depending on what rpm the belt let go at, also it could be carbon or rust in the cylenders from sitting, but usually if there is zero comp, the valves are bent. could only be one side though, either the intakes or exhaust

Not sure if you fiddled with the valve adjustment.
If they are adjusted too tight it could leave a valve hanging open, hence no compression.

What do you mean you did a leak down test and found the head is leaking air?
From where exactly is it leaking? Back through the intake, through exhaust system? Are you sure it was at TDC when did the check?