turning crank by hand with timing chain off

[gogg]

Alright we were rebuilding my motor (SOHC KA) and had the head bolted on and the valves set to TDC, as well as the pistons. The timing chain was OFF and my dad started to crank the pistons by hand, after yelling at him he said nothing would happen, and rotated the motor around back to TDC again.

My worry now is that he bent a valve, but he never exerted any extra force on any part while spinning it.

So, my question in essence is: Can you spin the pistons on a SOHC KA with the valves set at TDC and not mess anything up?

[nuts510]

all your father did was make you nervous, since you had the cam on top dead center and the lifters are about half flatten, the valves are not open very far so the pistons cleared if you had it in the position one of the valves was open all the way, you would have definitely felt the piston make contact with the valve and one would have to pull pretty hard on the crank to bend the valve. you gotta remember when engines are bending valves the motors rotating 2000 or 4000 or 8000 RPM's so the impact is much greater and does all the damage. Good luck with your motor rebuild and continue on.

[Red coupe]

could you bend a valve with your bare hands? cause that would probably be easier then turning the flywheel till one bent.