ENGINE
Inspecting the Cylinder Block and Components
5-38 6LY3 Service Manual
© 2007 Yanmar Marine International
Disassembling the Pistons
A floating-type piston pin is used in this engine. The
piston pin can be palm-pressed into the piston pin
hole at room temperature (coat with oil to make it
slide easily).
Figure 5-39
Figure 5-39
Measuring the Piston Pin
1. Measure the outside diameter of the piston pin
(Figure 5-41, (1)) as shown.
2. Replace the pin if it is worn beyond the stated
limits.
Figure 5-40
Figure 5-40
Measure at positions a, b and c in directions A and
B.
Figure 5-41
Figure 5-41
1 – Piston Pin Outside Diameter
Measuring the Piston Rings
There are two compression rings and one oil
control ring.
Figure 5-42
Figure 5-42
1 – Top Compression Ring
2 – Middle Compression Ring
3 – Oil Control Ring
• Measure the thickness and width of the rings.
• Measure the ring-to-groove clearance after
installing the ring on the piston.
• Replace if wear exceeds stated limits.
Piston Pin
Standard Limit
Piston Pin Hole
Inside Diameter
37.025-37.040 mm
(1.457-1.458 in.)
37.100 mm
(1.460 in.)
Piston Pin Outside
Diameter
36.994-37.000 mm
(1.4564-1.4566 in.)
36.964 mm
(1.4552 in.)
Clearance
0.025-0.046 mm
(0.0009-0.0018 in.)
0.110 mm
(0.0043 in.)
0005622
0005623
0005624
A
B
ab c
(1)
0005625
(1)
(2)
(3)
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