How to Do a Valve Adjustment

by Don Bowman

Valve adjustments are made with a cold engine--the purpose is to adjust the valves so that as the engine heats up and the valve adjusters expand, they do not keep the valves open. The valves need to have no more than one to three thousandths of an inch clearance when hot. Check the owners manual to make sure that the particular engine needs to have a valve adjustment and what the clearances should be when cold. The intake valve will be different then the exhaust.

Remove the air cleaner and associated hoses if obstructing the valve cover removal. Use the ¼-inch sockets and the common screwdriver for removal.

Remove the valve cover(s) using the ¼-inch sockets and ratchet.

Connect the remote starter switch by disconnecting the small wire on the starter at the terminal marked S. Connect one of the wires of the remote to the small terminal on the starter and the other wire on the positive terminal of the battery.

Identify the intake and exhaust valves location. The intake will be lined up with the intake manifold runners and the exhaust will be lined up with the exhaust manifold runners. Start with the intake valves. Hit the starter switch in short snaps and watch the valve you will be adjusting. To prepare for adjustment, the valve should go down (opened) and then come back up (closed). When the valve comes all the way up, hit the remote starter with one more quick snap to get the camshaft onto the heal of the lobe.

Feel the rocker arm and make sure it is loose--there should be no pressure on it. Loosen the lock nut with a 13mm wrench and an Allen wrench. The Allen should fit in the center of the stud. Hold the center of the stud with the Allen wrench and loosen the lock nut with the wrench.

Insert the appropriate feeler gauge as called for in the owner's manual or on the placard on the hood for the intake valve, in between the rocker arm and the valve spring. Turn the center stud with the Allen wrench until the rocker adjuster just touches the feeler gauge. The feeler gauge should slide in and out with minimal drag, but must have enough drag to indicate that the rocker is indeed touching the feeler.

Hold the Allen wrench from turning, when a slight drag can be felt, and tighten the lock nut with the wrench. Test the adjustment again by inserting the feeler gauge and try to move the rocker arm up and down by hand and feel for the drag on the feeler gauge. The feeler gauge should be able to be slid in and out freely but with a little effort. If there is friction or drag on the feeler gauge and no vertical movement of the rocker arm with the feeler gauge installed, the valve is set perfectly.

Move to the next valve and repeat the same process. When doing the exhaust valves remember to use the right feeler gauge for them and do them in the same manner (the adjustment is going to be different than the intake adjustment---check the owner's manual for the correct setting).

Install all parts in the reverse order of removal. Prior to putting the valve cover back on, inspect the gasket. If the gasket is old, worn, cracked or otherwise damaged, replace the gasket, else you will have oil leaks.

Items you will need

About the Author

Don Bowman has been writing for various websites and several online magazines since 2008. He has owned an auto service facility since 1982 and has over 45 years of technical experience as a master ASE tech. Bowman has a business degree from Pennsylvania State University and was an officer in the U.S. Army (aircraft maintenance officer, pilot, six Air Medal awards, two tours Vietnam).