Subaru 2002 IMPREZA Service Manual page 193

MECHANICAL
CYLINDER BLOCK
I
Standard
0.20
-
0.35
Top ring
4. PISTON RING
1) If the piston ring is broken, damaged, or worn, or
if its tension is insufficient, or when the piston
is
re-
placed, replace the piston ring with a new one of
the same size as the piston.
CAUTION:
"N" is marked on the end of the top and sec-
ond rings. When installing the rings to the pis-
ton, face this mark upward.
+
Limit
1 .O (0.039)
" N
3
I
EN0330
The oil ring is a combined ring consisting of
two rails and a spacer in between. When install-
ing, be careful to assemble correctly.
7
"N"
(A) Top ring
(6)
Second ring
(C) Oil ring
(a) Upper rail
(b) Spacer
(c) Lower rail
2) Squarely place the piston ring and oil ring in cyl-
inder, and measure the piston ring gap with a thick-
ness gauge.
1 .O (0.039)
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.
Unit: mm (in)
Standard
Limit
between pis-
ton ring and
groove ring
0.00281
B2M 1402
ME(D0HC TURBO)-87