How to Adjust Big Block Chevy Valves
Improperly adjusted valves are one of the most commonly overlooked causes of many engine problems, including misfires, a lack of power or high-speed performance, and backfires. Thankfully, adjusting the valves on a big block Chevy is much easier than on many other types of engines. The valves are actually adjusted while the engine is running, and the actual adjustment only requires a wrench.
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Instructions
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1
Start the engine and allow it to reach normal operating temperature, as indicated by the temperature gauge, then turn the engine off.
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2
Remove both valve covers with a wrench, then place a new valve cover gasket onto the each cylinder head. The gasket will prevent oil from spilling out of the cylinder heads as the valves are being adjusted.
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3
Make note of the single rocker arm nut located in the center of each of the sixteen rocker arms. These nuts will be turned to adjust the valves.
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4
Turn the engine on and allow it to idle.
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5
Loosen one rocker arm nut until a chattering sound is heard by turning the nut in a counterclockwise direction with a wrench. Once the chattering sound is heard, turn the rocker arm nut in a clockwise direction with a wrench until the chattering sound just stops. This is called the "zero lash" position.
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6
Turn the rocker arm nut a quarter of a turn, then wait for 10 seconds until the engine runs smoothly. Repeat this quarter turn four more times, pausing for 10 seconds between each quarter turn. The 10-second pause allows the valve lifter to adjust itself within its bore, thereby preventing the valve from striking the top of the piston. Repeat Steps 5 and 6 for the remaining 15 valves, then turn the engine off.
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7
Install the valve covers with new valve cover gaskets to complete the process.
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