Yanmar 4BY - Installation of Piston and Connecting Rod

ENGINE
BY Service Manual
5-39
Pistons and Cylinders
IMPORTANT
Pistons and wrist pins are matched. NEVER
mix parts.
6. Insert the wrist pin and install the second
retaining ring.
Figure 5-53
Note: Install piston rings with markings facing
up (Figure 5-53).
Figure 5-54
1 – Top Piston Ring
2 – Second Piston Ring
3 – Oil Ring
4 – Oil Ring Expander
7. Install the piston rings using a piston ring
installation tool. The oil ring (Figure 5-54, (3))
has an expander spring underneath it
(Figure 5-54, (4)). Install the expander end gap
and oil ring end gap 180° apart. Stagger all
exposed ring gaps 120° from each other with
none in line with the wrist pin.
Installation of Piston and Connecting
Rod
IMPORTANT
ALL parts that are being reused MUST be
installed in their original location and
orientation.
Figure 5-55
Figure 5-56
1. Bearing inserts for the connecting rod and rod
cap are different. Install bearing inserts having
an “S” and blue dye (Figure 5-56) in connecting
rod. Install bearing inserts having red dye
(Figure 5-55) in rod cap.
0003830
(4)
(1)
(2)
(3)