ABSTRACT
The valve guide shown in Fig. 3.3 is a hollow cylinder which is inserted into the cylinder head and its purpose is to ensure that the valve remains concentric with the valve seat. Valve guides are normally made from cast iron or phosphor bronze and they are made to be an interference fit in the cylinder head. In an alternative arrangement, that is sometimes used in cast iron cylinder heads, the valve guide is an integral part of the cylinder head. In operation the valve guide takes heat away from the valve and conducts it into the engine cooling system.
