Yanmar 3TNV82A-B Service Manual page 189

4-Valve Cylinder Head
(1)
Figure 6-52
Rocker Arm Shaft Outside Diameter
Use a micrometer to measure the rocker arm shaft
diameter (Figure 6-53). Measure at each rocker
arm location in two directions 90° apart
(Figure 6-53). See Rocker Arm and Shaft on
page 6-9 for the service limit.
Figure 6-53
TNV DI Service Manual
(1)
0001916
0001952
Inspection of Valve Guides
Valve Guide Inside Diameter
Visually inspect the valve guides for distortions,
scoring or other damage.
Note: Measure the valve guides while they are
installed in cylinder head.
Use a telescoping gauge and micrometer to
measure the inside diameter at each end of the
valve guide. Measure in three places and 90° apart
(Figure 6-54). See Intake / Exhaust Valve and
Guide on page 6-7 for the service limit. Replace the
valve guides if not within specification.
Figure 6-54
Inspection of Cylinder Head
Cylinder Head Distortion
Place the cylinder head flat and inverted
(combustion side up) on the bench. Use a straight
edge and feeler gauge to measure cylinder head
distortion (Figure 6-55). Measure diagonally and
along each side. See Cylinder Head on page 6-6
for the service limit.
Figure 6-55
ENGINE
0001869
0000192
6-57