Subaru Legacy 2002 Service Manual page 1093

Mechanical
4) Check circlip installation groove on the piston
for burr. If necessary, remove burr (A) from the
groove so that piston pin can lightly move.
5) Check piston pin circlip for distortion, cracks
and wear.
4. PISTON RING
S143090A1005
1) If piston ring is broken, damaged, or worn, or if
its tension is insufficient, or when the piston is
replaced, replace piston ring with a new one of the
same size as the piston.
CAUTION:
¼ Marks are shown on the end of the top and
second rings. When installing the rings to the
piston, face this mark upward.
¼ The oil ring is a combined ring consisting of
two rails and a spacer in between. When
installing, be careful to assemble correctly.
(A) Top ring
(B) Second ring
(C) Oil ring
(a) Upper rail
(b) Expander
(c) Lower rail
CYLINDER BLOCK
2) Squarely place piston ring and oil ring in
cylinder, and measure the piston ring gap with a
thickness gauge.
Piston
ring gap
B2M0420E
3) Measure the clearance between piston ring and
piston ring groove with a thickness gauge.
CAUTION:
Before measuring the clearance, clean the pis-
ton ring groove and piston ring.
Clearance
between pis-
ton ring and
piston ring
groove
Clearance between oil
ring and oil ring groove
EN1006
ME(H6)-72
Standard
0.20 — 0.35
Top ring
(0.0079 — 0.0138)
Second 0.35 — 0.50
ring (0.0138 — 0.0197)
Oil ring 0.20 — 0.60
rail (0.0079 — 0.0236)
Standard
0.040 — 0.080
Top ring (0.0016 —
0.0031)
0.030 — 0.070
Second
(0.0012 —
ring
0.0028)
0.065 — 0.155
(0.0026 —
0.0061)
Unit: mm (in)
Limit
1.0 (0.039)
1.0 (0.039)
1.5 (0.059)
B2M4107
Unit: mm (in)
Limit
0.15 (0.0059)
0.15 (0.0059)
—
B2M1402