5. Inspection and servicing of basic engine parts
119
(2) Measuring piston ring gap
Press the piston ring onto a piston liner and measure
the piston ring gap with a gauge. Press on the ring
about 30mm from the bottom of the liner.
(3) Removing the piston rings
1) Thoroughly clean the ring grooves when removing
piston rings.
2) The side with the manufacturer’s mark should
face up.
3) After fitting the piston ring, make sure it moves
easily and smoothly.
4) Stagger the piston rings at 120° intervals, making
sure none of them line up with the piston.
3YM30/3YM20 mm
Standard
Limit
Top ring gap
0.15-0.30
0.390
Second ring gap
0.18-0.33
0.420
Oil ring gap
0.20-0.45
0.540
Approx.
30 mm
Head surface
Cylinder block
Piston ring
Gap
Make the punched manufacturer's
mark face upward.
(Piston ring)
1st piston ring
2st piston ring
Oil ring
2st piston ring
120
120
120
Oil ring
1st piston ring
120
120
120
1st piston ring
2nd piston ring
Oil ring
Direction of
piston pin
Direction of side pressure
Summary of Contents for 3YM30
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