To set the lifter preload, turn the engine in its normal direction of rotation until the exhaust lifter just starts to travel upwards. 2. Adjust the intake valve to zero lash and then turn the rocker arm adjustment nut 1/4 to 1 turn. This additional turning of the adjustment nut sets the lifter preload. Different manufacturers may have different instructions, but you will notice they all stop at 1 turn. Check out the video below from our Design Engineer here at Scorpion on Valve Lash Adjustment.