Inspecting The Crankshaft - Yanmar 6LY3 series Service Manual

ENGINE
Inspecting the Piston Pin Bearing
Excessive wear to the piston pin bearing may result
in damage to the piston pin and / or the piston itself.
• Measure the inside diameter of the piston pin
bearing.
• Measure the outside diameter of the piston pin
See Measuring the Piston Pin on page 5-38.
• Calculate the oil clearance from the difference of
the two values.
• Compare readings with the specifications given.
Piston Pin Bushing Inside Diameter
Standard
37.025-37.040 mm
(1.457-1.458 in.)
Oil Clearance
Standard
0.025-0.046 mm
(0.0009-0.0018 in.)
NOTICE: The piston pin bearing is a
non-serviceable copper alloy bushing that is
factory-installed. The piston pin bearing comes
installed with the connecting rod assembly.
Figure 5-55
Figure 5-55
1 – Cylinder Gauge
5-44
Inspecting the Cylinder Block and Components
Limit
37.100 mm
(1.460 in.)
Limit
0.110 mm
(0.0043 in.)
(1)
0005639
© 2007 Yanmar Marine International

Inspecting the Crankshaft

The crank pins and crank journals have been
induction-hardened for superior durability. The
crankshaft (Figure 5-56, (2)) is designed with
balance weights (Figure 5-56, (1)) for minimum
vibration.
The crankshaft main bearings (Figure 5-56, (3))
are the hanger type. The upper bearing insert
(cylinder block side) is designed with an oil groove.
There is no oil groove on the lower bearing insert
(bearing cap side). The main bearing on the
flywheel end is equipped with a thrust bearing
(Figure 5-56, (9)), which supports thrust loads of
the engine.
Figure 5-56
(3)
(4)
(9)
(8)
(7)
Figure 5-56
1 – Balance Weight
2 – Crankshaft
3 – Main Bearing (Basic)
4 – Thrust Bearing
5 – Main Bearing (Intermediate)
6 – Main Bearing Cap (Intermediate)
7 – Main Bearing Bolt
8 – Main Bearing Cap (Basic)
9 – Thrust Bearing (Flywheel End)
6LY3 Service Manual
(1)
(2)
(5)
(6)
0005641