The valve springs can break over time and the valve stem seals can become defective; in either case, the individual components can be swapped without having to remove the cylinder heads due to a second method recommended by the manufacturer which also does not require removing the camshaft although a special tool exclusive to the SOHC engine is used. It is a valve spring compressor that just uses the camshaft as the fulcrum and with the aid of a ratchet to compress the spring and take off tension on the valve stem locks. The second procedure requires the utilization of a more familiar tool, but the valve springs are designed in such a way that they are recessed, and as a consequence, most clamp-type spring compressors cannot be employed unless the cylinder head is detached. When the cylinder head is pulled off, a normal C-clamp-type compressor is used on the spring pockets with an extension. For this operation, a compressed air source is sometimes required, therefore it is recommended to assemble the required tools in advance. The procedure starts with the dismantling of the valve cover and spark plug from the chosen cylinder and placing the piston on the top dead centre on the compression stroke. There is a thread air hose adapter inserted into the spark plug hole so that with the help of compressed air valve is held. Shop rags must be packed into the cylinder head holes to avoid that some parts may fall into the engine. The spring is then pushed to take out the
Rocker Arm and every component is labelled for ease of reassembling. With the spring compressed, the lock of the valve stem is un-fastened and the spring retainer, the valve spring and finally the valve stem seal. If air pressure cannot retain the valve closed further checks on the valve face and seat are required and in some cases cylinder heads may have to be removed for further valve repairs. The valve stem is tied with a rubber band or a tape after which, the valve is checked for damage, lubricated and a new seal is fitted. The spring and retainer are then placed and the stem lock of the valve is greased if required. When the lock is properly positioned, the air hose is disconnected and the rest of the installation performed in the same manner as the removal. Last of all, the engine is started again and the bonnet is kept open in order to observe whether there is any oil leakage and also to listen to any unusual sound that may be produced by the engine.