Subaru 2006 Legacy, Manual

Page: 2291 / 4302

ME(H4DOTC)-79
Cylinder Block
MECHANICAL
2. CYLINDER AND PISTON
1) The cylinder bore size is stamped on the cylinder
block front upper surface.
NOTE:
• Measurement should be performed at a temper-
ature of 20°C (68°F).
• Standard sized pistons are classified into two
grades, “A” and “B”. These grades should be used
as guide lines in selecting a standard piston.
Standard diameter:
A: 99.505 — 99.515 mm (3.9175 — 3.9179 in)
B: 99.495 — 99.505 mm (3.9171 — 3.9175 in)
2) How to measure the inner diameter of each cyl-
inder:
Measure the inner diameter of each cylinder in both
the thrust and piston pin directions at the heights as
shown in the figure, using a cylinder bore gauge.
NOTE:
Measurement should be performed at a tempera-
ture of 20°C (68°F).
Taper:
Standard
0.015 mm (0.0006 in)
Out-of-roundness:
Standard
0.010 mm (0.0004 in)
3) When the piston is to be replaced due to general
or cylinder wear, determine a suitable sized piston
by measuring the piston clearance.
(A) Main journal size mark
(B) Cylinder block (RH) – (LH) combination mark
(C) #1 cylinder bore size mark
(D) #2 cylinder bore size mark
(E) #3 cylinder bore size mark
(F) #4 cylinder bore size mark
ME-00170
#5
#4
#3
#2
#1
(A) (B)
(F)
(D)
AB
AB
54
54
(C) (E)
(A) Piston pin direction
(B) Thrust direction
H1: 10 mm (0.39 in)
H2: 45 mm (1.77 in)
H3: 80 mm (3.15 in)
H4: 115 mm (4.53 in)
ME-00171
(A) (B)
H2
H1
H3
H4
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