The tool levers against the cam to push down on the valvespring, unloading the follower and allowing you to remove it. Before compressing the valves to a particular cylinder, I checked the piston location by looking down the spark plug hole. If the piston was near the top, I turned the crank to move it farther down. Though it is unlikely you’d be able to bend a valve using this valvespring tool, why risk it? Even though I was not going to be reusing any of this stuff, there was no reason to damage perfectly good parts. Supposedly, turning the crank until the keyway points in the 10:30 position puts all the pistons in a safe position. I did this but still turned the crank slightly as needed while I removed the followers.