Yanmar 3JH3E - 3-3 Piston rings

Chapter 2 Ba.sic Engine
_3._P_1_·s_to_n_s_a_n_d_P_is_t_on_P_in_s ________________________ 3,4]H3(BXC)E
3-3 Piston rings
There are 2 compression rings and 1 oil ring.
The absence of
an oil ring on the piston skirt prevents oil
from being kept on the thrust surface and in tum provides
good lubrication.
A
~f"-8
A
Barrel face
8-side chrome piated,
A-side friction-proof
,,...-- hardening processed
Coil expander
3-3.1 Measuring the rings.
Measure the thickness and width of lhe rings, and the
ring-to-groove clearance after installation. Replace
if wear
exceed the !iml!.
Printed in Japan
HINSHI-H8009
Thickness
2-13
mm
Standard Weariimit
Groove width
2.065~2.080
--
First
piston Ring width
1.970~1.990
--
ring
Groove and
0. 075~0.11 O
ring clearance
0.2
Groove width 2.035~2.050
--
Second
piston
Ring width
1.970~ 1.990
--
rtng
Groove and
0.2
ring clearance
0.045~0.080
Groove width 4.015~4.030
--
Oil ring
Ring width
3.975~3.990
--
Groove and
0.025~0.060
0.2
,ing clearance
3-3.2 Measuring piston ring gap
Press the piston ring onto a pfston liner and measure the
piston
ring gap with a gauge. Press on the ring about
30mm from the bottom of the liner.
Piston ring
Cylinder lrner
Gap
mm
Standard Wear limit
First piston ring gap
0.20~0.40 1.5
Second piston ring gap 0.20~0.40
1.5
Oil ring gap 0.20~0.40
1.5