The idea is to determine the origin of the leak - more the better since it will be easier to hear. Hear it in the intake it is an intake valve. Hear it in the crankcase it is rings or hole in the piston. Hear it in the tail pipe then it is an exhaust valve. When you are turning the engine I hope you are using the bolt on the crankshaft/balancer and not the bolt on the cam sprocket. Snap either of those cam bolts off and you will add to a bad day.