I repaced the head gasket on my 16hp kohler 460s and when I go to reinstall my rocker arms(non adjustible) I notice that when tightening, the valve spring compresses slightly before the mounting bolt is completely tightened. I made sure the lifter was completely off the cam lobe and the pushrod is positioned correctly. Wouldn't any movement of the valve spring result in opening of the respective valve? I am a bit of a rookie with lawn tractor stuff. Any direction would be helpful. Thanks.