SERVICE MANUAL
CYLINDER HEAD & VALVES
Section 3
ENGINE GEAR TRAIN TIMING
Valve train failures from broken or bent push rods,
valves, rocker arms and worn valve keepers and/or
rotators in many instances have been found to be
caused by improper timing of the gear train. Depending
on valve lash setting, if the camshaft gear is improperly
timed by one (1) tooth early, the engine pistons will strike
the intake valve heads or if the timing is set one (1) tooth
late, the exhaust valve may contact pistons.
IN ALL CASES OF THE ABOVE, GEAR TRAIN TIMING
CAN BE VERIFIED WITHOUT REMOVAL OF ENGINE
FRONT COVER AND/OR TEAR DOWN.
IMPORTANT: The revised intake ramp height of the
new 400 Series Camshaft requires the engine gear
train timing specification be increased from .60 mm
(0.024 in.) to .74 mm (0.029 in). Two methods are
available when checking engine gear train timing
without removal of front cover and/or engine tear
down.
CGES-185-3
PRINTED IN UNITED STATES OF AMERICA
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