Remove the spark plugs and the valve covers, camshafts and rocker arms. Thread an adapter into the spark plug hole and connect an air hose from a compressed air source to it. Most auto parts stores can supply the air hose adapter. Apply compressed air to the cylinder. The valves should be held in place by the air pressure. Using a socket and a hammer, gently tap on the top of each valve spring retainer several times, then use a valve-spring compressor to compress the spring. Remove the keepers with small needle-nose pliers or a magnet. Remove the valve spring and retainer. Remove the old Valve Stem Oil Seals, noting differences between the intake and exhaust seals. Wrap a rubber band or tape around the top of the valve stem so the valve won't fall into the combustion chamber, then release the air pressure. Inspect the valve stem for damage. Rotate the valve in the guide and check the end for eccentric movement. Move the valve up-and-down in the guide and make sure it does not bind. Reapply air pressure to the cylinder to retain the valve in the closed position, then remove the tape or rubber band from the valve stem. If you're working on an exhaust valve, fit the new exhaust Valve Stem Oil Seal on the valve stem and press it down over the valve guide. If you're working on an intake valve, install a new intake Valve Stem Oil Seal over the valve stem and press it down over the valve guide. Install the spring and retainer in position over the valve. Compress the valve spring assembly only enough to install the keepers in the valve stem. Position the keepers in the valve stem groove. Apply a small dab of grease to the inside of each keeper to hold it in place if necessary. Remove the pressure from the spring tool and make sure the keepers are seated. Disconnect the air hose and remove the adapter from the spark plug hole. Repeat the above procedure on the remaining cylinders. Install the rocker arm assemblies, camshafts, timing chains and the valve covers. Start the engine, then check for oil leaks and unusual sounds coming from the valve cover area. Allow the engine to idle for at least five minutes before revving the engine.
