Yanmar 3TNV82A Service Manual page 212

ENGINE
Note: If installing new piston rings the end gap
must be checked and adjusted as
necessary. See Inspection of Pistons,
Piston Rings and Wrist Pin on page 6-78
for specifications. Use a piston ring end
gap filing tool to adjust the piston ring
end gap on new piston rings.
Note: Reinstall the top and second piston rings
with the stamped "makers mark"
(Figure 6-131, (1)) facing the top of the
piston. The "makers mark" may vary in
appearance but will always be located on
the top surface of the piston ring
adjacent to the piston ring gap. The oil
ring and oil ring expander can be
installed either side up.
Figure 6-131
IMPORTANT
Always use a piston ring installation tool
(expander) when installing piston rings.
Never attempt to install piston rings by
hand.
7. Reinstall the oil ring expander
(Figure 6-132, (4)). Reinstall the oil ring
(Figure 6-132, (3)) with the end gap at 180°
from the expander end gap.
8. Reinstall the second compression ring
(Figure 6-132, (2)). This ring is identified by its
dark color and tapered face profile.
9. Reinstall the top compression ring
(Figure 6-132, (1)). This ring is identified by its
silver color and barrel-shaped face profile.
IMPORTANT
The oil ring expander (Figure 6-132, (4))
end gap must be located 180° from the oil
ring (Figure 6-132, (3)) end gap.
6-86
(1)
0000225A
Crankshaft and Camshaft Components
(4)
Figure 6-132
10. Stagger the piston ring end gaps at 120°
intervals (Figure 6-133, (1, 2, 3)). Do not
position the top piston ring end gap in line with
the wrist pin.
(2)
1 – Top Compression Ring End Gap
2 – Second Compression Ring End Gap
3 – Oil Ring End Gap
Figure 6-133
TNV DI Service Manual
(1)
(2)
(3)
0001722B
(1)
(3)
0001968