SERVICE MANUAL
VALVE TRAIN - CAMSHAFT, TAPPETS & PUSH RODS
Section 4
Design changes to improve initial lubrication to valve
train components have been made by revising the rocker
shafts and rocker arms on 400 Series engines. Rocker
shafts were revised by drilling 3.1750 mm (.125 in.)
diameter holes through the shaft while the rocker arm
assembly oil hole was relocated to a vertical position.
Figures 9 and 10 illustrate the displaced and new
components.
Engines built with and after the following serial numbers
incorporate the new rocker arm and rocker arm shaft:
Engine
Serial Number
D-312
8499
D/DT-360
13716
DT-414
103448
DT-414B
140000
D/DT-436
46359
DT-436B
100000
D/DT-466
21868
DT/DTI-466B
75000
DT/DTI-466C
400001
IMPORTANT
1.
Displaced shafts must NOT be used with new
rocker arms.
2.
New shaft may be used with EITHER new or
displaced rocker arms.
Figure 9. - Rocker Arm
Figure 10. - Rocker Arm ShaftCG-6459
CGES-185-3
PRINTED IN UNITED STATES OF AMERICA
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