what could have caused this?

[chino12]

so today i got the case from the welder, i hope it will hold
so then i went to the garage, cleaned the case and put in the pistons rods and shaft

and assumed that top dead center is when piston 1 and 4 are at the top of the cylinder - that was to me the only way for the rods to be straight
i tighten the the rods to 25nm as written in book

i then tried to rotate the shaft but i couldnt

could this be because of the new set of rods&pistons which might not be aligned to the cylinder?
or i did some stupid shit ...