Subaru Impreza 2004 - Page 97

ME(H4SO)-4
MECHANICAL
General Description
Cylinder
block
Surface warpage limit (mating with cylinder head) 0.05 mm (0.0020 in)
Surface grinding limit 0.1 mm (0.004 in)
Standard height 201.0 mm (7.91 in)
Cylinder bore
1.6 L STD
A 87.905 — 87.915 mm (3.4608 — 3.4612 in)
B 87.895 — 87.905 mm (3.4604 — 3.4608 in)
2.0 L STD
A 92.005 — 92.015 mm (3.6222 — 3.6226 in)
B 91.995 — 92.005 mm (3.6218 — 3.6222 in)
2.5 L STD
A 99.505 — 99.515 mm (3.9175 — 3.9179 in)
B 99.495 — 99.505 mm (3.9171 — 3.9175 in)
Taper
STD 0.015 mm (0.0006 in)
Limit 0.050 mm (0.0020 in)
Out-of-roundness
STD 0.010 mm (0.0004 in)
Limit 0.050 mm (0.0020 in)
Piston clearance
STD 0.010 — 0.030 mm (0.0004 — 0.0012 in)
Limit 0.050 mm (0.0020 in)
Enlarging (boring) limit 0.5 mm (0.020 in)
Piston
Outer diameter
1.6 L
STD
A 87.885 — 87.895 mm (3.4600 — 3.4604 in)
B 87.875 — 87.885 mm (3.4596 — 3.4600 in)
0.25 mm (0.0098 in)
OS
88.125 — 88.135 mm (3.4695 — 3.4699 in)
0.50 mm (0.0197 in)
OS
88.375 — 88.385 mm (3.4793 — 3.4797 in)
2.0 L
STD
A 91.985 — 91.995 mm (3.6214 — 3.6218 in)
B 91.975 — 91.985 mm (3.6211 — 3.6214 in)
0.25 mm (0.0098 in)
OS
92.225 — 92.235 mm (3.6309 — 3.6313 in)
0.50 mm (0.0197 in)
OS
92.475 — 92.485 mm (3.6407 — 3.6411 in)
2.5 L
STD
A 99.485 — 99.495 mm (3.9167 — 3.9171 in)
B 99.475 — 99.485 mm (3.9163 — 3.9167 in)
0.25 mm (0.0098 in)
OS
99.725 — 99.735 mm (3.9262 — 3.9266 in)
0.50 mm (0.0197 in)
OS
99.975 — 99.985 mm (3.9360 — 3.9364 in)
Standard inner diameter of piston pin hole 23.000 — 23.006 mm (0.9055 — 0.9057 in)
Piston pin
Outer diameter 22.994 — 23.000 mm (0.9053 — 0.9055 in)
Standard clearance between piston pin and hole in pis-
ton
0.004 — 0.008 mm (0.0002 — 0.0003 in)
Degree of fit
Piston pin must be fitted into position with thumb at 20°C
(68°F).
Piston ring
Piston ring gap
Top ring
STD 0.20 — 0.35 mm (0.0079 — 0.0138 in)
Limit 1.0 mm (0.039 in)
Second
ring
STD
1.6 L,
2.5 L
0.35 — 0.50 mm (0.0138 — 0.0197 in)
2.0 L 0.40 — 0.50 mm (0.0157 — 0.0197 in)
Limit 1.0 mm (0.039 in)
Oil ring
STD 0.20 — 0.50 mm (0.0079 — 0.0197 in)
Limit 1.5 mm (0.059 in)
Clearance
between piston
ring and piston
ring groove
Top ring
STD 0.040 — 0.080 mm (0.0016 — 0.0031 in)
Limit 0.15 mm (0.0059 in)
Second
ring
STD 0.030 — 0.070 mm (0.0012 — 0.0028 in)
Limit 0.15 mm (0.0059 in)