Inspecting Valve Springs - Navistar INTERNATIONAL DT 466 Service Manual

Inspecting Valve Springs

1. Clean all of the valve springs in a suitable solvent.
CAUTION: To prevent engine damage, do not wire
brush or grind valve springs. Disruption of surface
may result in fatigue cracks and spring failure.
2. Check the valve springs for rust, cracks, and
pitting. Replace any damaged valve springs.
Figure 184 Valve spring inspection
3. Check both ends of each valve spring at the
contact point between the cutoff end of the last
coil and the adjacent coil. If the cutoff end has
worn a notch in the adjacent coil, replace the
spring.
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
CYLINDER HEAD AND VALVE TRAIN
EGES-265-2
Follow all warnings, cautions, and notes.
© 2009 Navistar, Inc.
NOTE: These wear notches can also be detected
by compressing the spring and listening for a
clicking sound.
Figure 185 Checking perpendicularity and
flatness of valve spring
NOTE: Valve springs that are not perpendicular to a
flat surface place an unequal lateral load on the valve
stem during operation, causing premature valve guide
wear.
4. Use a square
perpendicularity of spring ends.
of any valve spring is not flat and square, replace
spring.
139
to check flatness
If the end
and