Cylinder
Block
Inspection
Inspect the cylinder block. If it is found defective, repair
or
replace the block.
Cylinder Bore (mm):
Mgdel
20B
30B
Standard
76
+ 0.03 -0.0
76 + 0.03 -0.0
Wear Umit Before Rebore: + 0.02 mm
Cylinder
Reboring
When reboring a cylinder, use the following procedure.
1.
Select a piston size: 0.25
as
or
0.50
as.
2.
Measure the piston diameter.
3. Reboring finish
dimension
=
[piston
00]
+
[clearance] - [honing allowance (0.2 mm)]
Clearance (between piston and cylinder)
Standard:
0.071
- 0.084 mm (A-D)
CAUTION
A
ox.10mm
ppr
from upper end
C
enter
Front
~
~\J7
,
L
-
'--
ower
Measuring position
Cylinder Bore Measuring Positions
Direction
of
measuing
I~
55
l
mm
0
Measure
diameter
here
----L.-~r
Measuring
Piston
Diameter
When it is necessary for a cylinder
to
be rebored
to
the next over size, the remainders must
also be rebored
to
the same over size.
55 Westerbeke Engines