Yanmar 4TNE98, Service Manual

Page: 104 / 246

4TNV98 & 4TNE98 Diesel Engine Section 3. Engine 102
NOTE : To properly align the rocker arm shaft with
the rocker arm shaft supports, first reinstall one of
the end rocker arm supports
(Figure 6-72, (6)) with
a hole for the shaft alignment stud (Figure 6-72, (5)) .
Align the hole in the rocker arm shaft and the hole in
the rocker arm support bracket. Reinstall the
alignment stud.
Figure 6-72
NOTE : Figure 6-72 shows components for one
cylinder. Components for all remaining cylinders are
assembled in the same order.
4. Position the rocker arm assembly on a flat surface.
Reinstall the alignment studs (Figure 6-72, (5)) .
5. Place the rocker arm shaft assembly onto the
cylinder head.
6. If removed, reinstall the valve adjusting screws
(Figure 6-72, (2)) and lock nuts (Figure 6-72, (3)) .
7. Align the push rods with their respective rocker
arms.
8. Reinstall and tighten the rocker arm shaft
retaining bolts to the specified torque.
9. Tighten the rocker arm shaft alignment studs.
10. Adjust the valve clearance.
11. Reinstall the fuel injectors. See Installation of the
Fuel Injectors on page 167.
4TNE98 Engine
1.
Lubricate the rocker arm shaft. Slide the rocker
arm support brackets (Figure 6-30, (4)), springs
(Figure 6-30, (5)) and rocker arms (Figure 6-30,
(6)) onto the shaft.
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 : To properly align the rocker arm shaft with
the rocker arm shaft supports, first install the rocker
arm support bracket
(Figure 6-31, (4)) with the hole
for the shaft alignment screw (Figure 6-31, (1)) .
Align the hole in the rocker arm shaft and the hole in
the rocker arm support bracket. Install the alignment
screw.
Figure 6-31
2. Position the rocker arm assembly on a flat surface.
Install the retaining rings (Figure 6-31, (3)) onto
the end of the rocker arm shaft.
3. Install and hand tighten the rocker arm shaft
retaining bolt and nuts.
4. Install the valve adjusting screws (Figure 6-31,
(7)) and lock nuts (Figure 6-31, (8)) .
5.
Place the rocker arm assembly in place onto the
cylinder head. Tighten the rocker arm support
bracket nuts and bolt to the specified torque.
Tighten the rocker arm shaft alignment screw.
6. Align the push rods with their respective rocker
arms and adjust the valve lash. (See Measuring
and Adjusting Valve Clearanceon page 104.)