Mitsubishi 4G1 Service Manual page 281

BORING CYLINDER
basis of the largest bore cylinder.
Size
Thrust
direction
mm (.Ol in.) O.S.
0.25
mm (.02 in.) OS.
0.50
mm (.03 in.) O.S.
0.75
1 .OO mm (.04 in.) O.S.
NOTE
Size mark is stamped on the piston top.
(2) Measure outside diameter of piston to be used. Measure it
in thrust direction as shown.
(3) Based on the measured piston O.D., calculate the boring
finish dimension.
Boring finish dimension = Piston O.D. + (Clearance
between piston O.D. and cylinder) - 0.02 mm (.0008 in.)
(honing margin)
(4) Bore all cylinders to the calculated boring finish dimension.
Caution
To prevent distortion that may result from temperature
rise during honing, bore cylinders! in the order of No. 2,
No. 4, No. 1 and No. 3.
(5) Hone to the final finish dimension (piston O.D. + clearance
between piston O.D. and cylinder.)
(6) Check the clearance between piston and cylinder.
Clearance between piston and cylinder:
0.02 - 0.04 mm (.OOOS - .0016 in.)
NOTE
When boring cylinders, finish all of four cylinders to the
same oversize. Do not bore only one cylinder to an oversize.
Piston size identification
Identification mark
0.25
0.50
0.75
1.00