Chevrolet rocker arms act like a pendulum, in that each rocker arm rocks back and forth on a threaded stud. As the engine rotates, the camshaft causes the rocker arm to press down on the top of a valve via a pushrod. A spring located on the top of the valve then causes the rocker arm to return to its starting position. Roller rocker arms feature a metal cylinder that spins on the tip of the valve, rather than sliding against the valve as with conventional rocker arms. However, as is the case with conventional rockers, roller rockers must be adjusted.
Remove the bolts that secure the valve cover to the top of the cylinder head using a wrench, then lift the valve cover off the cylinder head.
Peel the gasket off the interior lip of the valve cover, then remove any gasket debris from the top of the cylinder head by spraying a small amount of engine degreaser onto a lint-free rag and wiping the surface clean.
Locate each rocker arm’s adjusting nut. Each rocker arm has a single adjusting nut, located at the top of the rocker arm. This adjusting nut is what determines the valve lash of the rocker arm.
Start the engine and allow it to idle.
Loosen the adjusting nut on one rocker arm with a deep-set socket connected to a socket wrench until a clacking sound can be heard, then tighten the nut just until the clacking stops. This is the zero-lash position.
Tighten the rocker arm’s adjusting nut to the proper setting with the socket wrench. The proper setting for the vast majority of Chevrolet engines is one full turn, meaning that the adjusting nut must be turned in a clockwise direction for one 360-degree turn. Some Chevy engines require a different setting, so always consult the engine’s specifications manual to check the proper setting.
Repeat Steps 5 and 6 for the remaining rocker arms, then turn the engine off and allow it to cool.
Apply a single bead of gasket sealant to each side of a replacement valve cover gasket, then place the gasket onto the inner lip of the cover and lower the cover onto the cylinder head.
Tighten the valve cover’s retaining nuts with a wrench.
