9.5
Section 9
Inspection and Reconditioning
9
Hard starting, or loss of power accompanied by high fuel consumption may be symptoms of faulty valves.
Although these symptoms could also be a ributed to worn rings, remove and check the valves fi rst. A er
removal, clean the valve heads, faces, and stems with a power wire brush. Then, carefully inspect each valve for
defects such as warped head, excessive corrosion, or worn stem end. Replace valves found to be in bad condition.
A normal valve and valves in bad condition are shown in the accompanying illustrations.
Normal: Even a er long hours of operation a valve
can be reconditioned and reused if the face and
margin are in good shape. If a valve is worn to where
the margin is less than 1/32 in. do not reuse it. The
valve shown was in operation for almost 1000 hours
under controlled test conditions.
Bad Condition: The valve depicted here should be
replaced. Note the warped head; margin damaged
and too narrow. These conditions could be a ributed
to excessive hours or a combination of poor operating
conditions.
Leakage: A poor grind on face or seat of valve will
allow leakage resulting in a burned valve on one side
only.
Coking: Coking is normal on intake valves and is not
harmful. If the seat is good, the valve could be reused
a er cleaning.
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