The seatings in the Head can then be cleaned up by using a 45 deg. cutter with a pilot 5/16-in. diameter, 4-in. long, for the inlet valve guide and a 3/8in. pilot will be needed for the exhaust guide.

After prolonged service, and repeated cutting, the Seatings may become sunk well below the surrounding surface of the combustion chamber, and this condition lowers the efficiency of the engine. In such circumstances it may be necessary for new valve seats to be inserted - a factory job.

The Valve guides are detachable, and may be removed and new ones fitted with a double diameter soft punch or drift. The small end should be 5/16-in. diameter for about 2-in., and the remainder ½-in. diameter approximately 4-in. long. Drive out the guides from inside the ports, but do not remove them unless they are worn or damaged so as to need replacement.