Yanmar 4TNE98, Service Manual

Page: 92 / 246

4TNV98 & 4TNE98 Diesel Engine Section 3. Engine 90
Figure 6-4
3. Remove the valve cover (Figure 6-4, (3)) . Discard
the valve cover gasket (Figure 6-4, (4)) .
Removal of Rocker Arm Assembly
1.
Remove the bolt (Figure 6-6, (1)) and locking
nuts (Figure 6-6, (2)) that retain the rocker arm
support brackets to the cylinder head.
2. Lift the rocker arm assembly from the cylinder
head.
3. Lift the push rods from the cylinder head.
4. Number the push rods so that they are reinstalled
with the same valve tappet and rocker arm.
Figure 6-6
Disassembly of Rocker Arm Assembly
1.
Remove the rocker arm shaft alignment screw
(Figure 6-7, (1)) from the support bracket that
secures the rocker arm shaft (Figure 6-7, (2)) .
2. Remove the retaining rings (Figure 6-7, (3)) from
the ends of the rocker arm shaft (Figure 6-7, (2)) .
3. Slide the rocker arm shaft (Figure 6-7, (2)) out of
the rocker arm support brackets (Figure 6-7, (4)) ,
springs (Figure 6-7, (5)) , and rocker arms (Figure
-7, (6)) .
NOTE : The rocker arm shaft fits tightly in the rocker
arm support brackets. Clamp the support bracket in
a padded vise and twist the rocker arm shaft to
remove. Reverse this process when you reinstall the
rocker arm shaft into the support brackets.
NOTE : Mark the rocker arms so they can be
reinstalled with the original matching valve and
pushrod.