Adjusting the valves on your Honda Accord can, in many cases, restore idle quality and performance that has been lost due to engine wear. The key to performing this procedure successfully is to avoid rushing through it. Take it one step at a time, and adjust each valve in exactly the same way. This project is possible for the experienced home mechanic and does not require special tools or equipment.
Remove the 10mm bolts that attach the valve cover to the cylinder head and the timing cover. Remove the valve cover and valve cover gasket from the cylinder head, and remove the upper timing cover from the engine. Remove the spark plugs.
Rotate the engine to top dead center on the number one cylinder compression stroke. Place a finger into the spark plug opening in the cylinder head and feel the compression as the engine nears top dead center to verify it is on the compression stroke. Stop when the timing mark on the crankshaft pulley indicates top dead center. The timing mark/pointer on the camshaft pulley will be straight up.
Refer to the service manual for the valve clearance specifications for your specific year and model. The specifications changed from engine to engine, and year to year. Valve clearance specifications are also listed on the emissions tag under the hood. Note that the clearance for the exhaust valves is not the same as the clearance for the intake valves. Slip the correct thickness feeler gauge under the valve rocker arm. Loosen the lock nut, and tighten the adjuster screw until there is a slight drag on the feeler gauge as it is moved. Tighten the lock nut, and check the clearance again. It is not unusual for the adjuster screw to tighten as the lock nut tightens, so it may take a few tries to get it right. Adjust both the intake and exhaust valves on the number one cylinder.
Rotate crankshaft 180 degrees counterclockwise. The camshaft will turn 90 degrees, and the timing mark/pointer on the cam gear will be 90 degrees from straight up. Adjust the valves, intake and exhaust, on the number three cylinder.
Rotate the crankshaft an additional 180 degrees; the cam gear will now point straight down. Adjust all of the valves on the number four cylinder.
Rotate the crankshaft 180 degrees one more time, and adjust the valves on the number two cylinder.
Reinstall the valve cover using a new gasket and the original 10mm bolts. Bolt the timing cover back onto the engine and front of the valve cover. Start the engine and let idle. Test drive to verify the repair.
