Yanmar 3TNV88F Service Manual page 125

Crankshaft and Camshaft Components
■ Replacement of crankshaft oil seals
1. Remove the seal (Figure 6-63, (2)) from the
cover (Figure 6-63, (1)).
2. Apply a continuous bead of ThreeBond Liquid
Gasket No. 1207F, YANMAR Part No. 977770-
1207F to the outside diameter of a new oil seal
(Figure 6-63, (2)), and install in the gear case
cover. Apply lithium grease to the lip of the seal.
Figure 6-63
3. Remove the rear oil seal (Figure 6-64, (3)) from
the seal housing (Figure 6-64, (2)).
4. Apply a continuous bead of ThreeBond Liquid
Gasket No. 1207F, YANMAR Part No. 977770-
1207F to the outside diameter of a new oil seal
(Figure 6-64, (2)), and install in the housing.
Apply lithium grease to the lip of the seal.
1
Figure 6-64
3TNV88F Service Manual
1
2
046360-00X00
2
3
K0001707A
■ Measure crankshaft bearing oil clearance
Oil clearance should be checked during
disassembly to determine the extent of wear, and
during assembly to ensure long engine life. The
same procedure is done for both connecting rods
and main bearings.
■ Inspection of cylinder block
1. Ensure that oil passages are clear and
unobstructed.
2. Check for discoloration or evidence of cracks. If
a fracture is suspected, use the color check
method or the Magnaflux method to determine
if the cylinder block is fractured.
3. Inspect cylinders for roundness, taper, or
evidence of scoring. Collect and record the
measurements. Consider honing, reboring or
replacing the cylinder block if the
measurements are not within specification.
• Take measurements at three places
(Figure 6-65) (a, b, c), and in two directions (d
and e) in each cylinder.
a
b
c
20 mm
(0.75 in.)
Figure 6-65
■ Inspection of pistons, piston rings and
wrist pin
Note:
• On an engine with low hours, the pistons, piston
rings may be reused if they are found to be within
specifications. The pistons and piston rings must
be reinstalled in the same cylinders from which
they were originally removed.
• On an engine with high hours, the pistons rings
should be replaced and the cylinder honed (See
Honing and Boring on page 6-46) or replaced.
The piston should be replaced as necessary.
ENGINE
20 mm
(0.75 in.)
d
e
K0000230B
6-41