marks. Follow the instructions supplied by the manufacturer of the honing machinery.
(7) Machined surfaces. Check the machined surfaces of the cylinder block with a straightedge. If the
machined surfaces are worn or warped to the extent that a 0.010-inch feeler gage can be passed between
the straightedge and the machined surface, replace the cylinder block.
(8) Planing and milling. Do not attempt to plane or mill the top of the cylinder head to remove warpage or high
spots. Any amount of metal removed from the face of the cylinder head will change the compression ratio
of the engine and in many instances will cause a sharp detonation spark knock.
182. Camshaft and Cam Gear
a. General. The camshaft used on this engine is an alloy steel forging and operates in solid bronze bushings which
are assembled to the cylinder block. The camshaft and crankshaft gears are helical cut and have a maximum tooth
contact surface. Several parts of the teeth are engaged at one time, and this sliding action increases the strength and
reduces the gear noise. All bearings and cam faces are ground to extremely hard surface and should not cause any
trouble during the life time of the engine. It is seldom, if ever, necessary to replace the camshaft and bushings.
b. Removal.
(1) Remove the engine (par. 174b).
(2) Remove the fan drive pulley (par. 180b).
(3) Remove the governor (par. 108b).
(4) Remove the magneto (par. 116c).
(5) Remove the screws (10, 11, and 14, fig. 92), lockwashers (2), plain washers (6 and 13), and nuts (9)
attaching the timing gear cover (15) to the cylinder block.
(6) Remove the timing gear cover (15) and inspect the seal (12) for wear, breaks, and damage. Drive out the
seal and replace it if worn or damaged.
(7) Remove the timing gear cover gasket (5). Clean the gasket mounting surface with dry-cleaning solvent and
make sure that the surface is clean and smooth.
(8) Drive the edge of the camshaft gear nut lockwasher away from the nut and remove the camshaft gear nut
and lockwasher.
(9) Use a camshaft gear puller (2, fig 93) to pull the camshaft gear (3) off the camshaft (4).
(10) Use a blunt screwdriver to remove the camshaft gear key (7, fig. 94) from the camshaft (1). Be extremely
careful
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