Setting Valve Lash on Hydraulic Lifters
Setting valve lash for the first time can seem like a daunting task, but as often as it’s overlooked it’s extremely important to get the best performance out of your engine. Valve lash is defined as the mechanical clearance between the tip of the rocker arm and the valve stem tip. If there is too much valve clearance it will decrease the duration of lift, lead to excessive wear on valvetrain, and cause noise in the engine. Too tight and the valves can hang open causing poor performance and excessive wear on valvetrain components. There are several methods to setting valve lash, but if you follow the firing order of the engine, you’ll only need to rotate the cam one full turn (2 crankshaft rotations) to complete this procedure.
- To get started, make sure the engine is cold. You can use timing tape on the balancer or very carefully measure and mark the balancer every 90 degrees to double check the engine's rotation.
- Be sure to apply a generous amount of high quality assembly lube like Isky Rev Lube or Red Line oil on all of the contact surfaces before starting.
- With the valve covers off and spark plugs removed, rotate your engine to top dead center compression stroke on the number one cylinder. Do this by watching the movement of the lifters or rocker arms – the exhaust will open first, then the intake. As soon as the intake returns to its fully closed position you’ve reached the compression stroke.
- Now you can set the valve lash on both the intake and exhaust valve. Most hydraulic lift camshafts will require zero lash for the proper adjustment. The process will be the same whether you have stamped steel rockers or roller tip rockers.
- To achieve zero lash, tighten down the rocker as you spin the push rod in your fingers, do this until you notice slight resistance as you spin the pushrod (this is zero lash). You should also no longer have any lateral movement in the pushrod.
- When you know you’ve hit zero lash, tighten the rocker another 1/2 turn to set the optimum preload on the lifter, pushrod and rocker arm.
- Move to the number two cylinder in the firing order and the intake valve should already be open. Then rotate the engine over another 90 degrees or 1/4 turn clockwise while watching the lifters to ensure you're on the base circle of the camshaft lobe and repeat the adjustment procedure.
- As you move through the firing order the intake valve should be open on each cylinder. Simply follow the procedure on each cylinder and be consistant as you tighten each rocker.