Rocker Arms - Navistar INTERNATIONAL DT 466 Service Manual

126
Figure 149 Measuring rocker arm shaft
1. Check the rocker shaft for scoring, pitting and
wear. Replace rocker shaft and all of the rocker
arms as required.
NOTE: It is normal to see a slight polishing at the
rocker arm area.
2. Use an outside micrometer to measure a
non-contact area of the rocker shaft.
dimension will be used as a baseline for the
shaft diameter.
3. Use an outside micrometer to measure each of
the 12 lever contact areas of the rocker shaft. If
the difference between the baseline and any of the
measurements is greater than 0.03 mm (0.001 in),
replace the rocker shaft and all of the rocker arms.
4. To ensure that oil supply holes are open, insert a
small wire or another suitable tool.
5. Check the cup plugs at each end of the rocker
shaft. Do not disturb the cup plugs unless they
are damaged. If replacement is required, pry out
the plugs and press in new plugs.

Rocker Arms

1. Inspect arms for scoring, pitting, or signs of
excessive wear. If the bore has visible damage,
replace the rocker arm. Be sure to inspect the
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
CYLINDER HEAD AND VALVE TRAIN
This
EGES-265-2
Follow all warnings, cautions, and notes.
© 2009 Navistar, Inc.
lower half of the rocker arm. The most significant
wear will occur at this location.
may be reused in their original locations if the
phosphate coating is worn off and the shaft was
not replaced.
Figure 150 Measuring the rocker arm bore
NOTE: The purpose of the black phosphate
coating on the rocker arm is to provide a break-in
lubricant between the rocker shaft and rocker
arm bore. It is normal to see the black phosphate
coatings worn off of the bottom of the lever arm
in the shaft and bore contact area. Rocker arms
must be labeled and installed in their original
locations to maintain the proper wear pattern.
2. Use a telescoping gauge and outside micrometer
to measure the rocker arm bore diameter at two
locations. Measure the diameter at A-B and C-D.
If the difference between the diameters is greater
than or equal to 0.03 mm (0.001 in), replace the
rocker arm.
3. Inspect the valve bridge contact pivot on the
rocker arm for scoring, pitting, or signs of
excessive wear.
4. Inspect the valve lash adjuster for signs of wear.
Replace the adjuster screw if excessive wear is
found.
Rocker arms