i have a question but not sure if i am in the right place, but here goes. i am in the process of replacing water pump,rad.hoses, thermostat and belts.my question is when replacing the belts i read the wrench trick to keep the right pulley from turning.i also read about backing off the tension on the valve tappets.i like this idea but not sure if i go backing off the tappets if i can unscrew something too much or springs will come flying out or if i can mess anything up?