Mitsubishi Motors 4G9 - Manual (Page 164)

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4G9 ENGINE (E–W) –
Crankshaft, Cylinder Block, Flywheel and Drive Plate
11A-12-6
PWEE9502-A
E
Nov. 1995 Mitsubishi Motors Corporation Revised
CYLINDER BLOCK
(1) Using a straightedge and thickness gauge, check the
block top surface for warpage. Make sure that the surface
is free from gasket chips and other foreign matter.
Standard value: 0.05 mm or less
Limit: 0.1 mm
(2) If the distortion is excessive, correct within the allowable
limit or replace.
Grinding limit: 0.2 mm
The total thickness of the stock allowed to be
removed from cylinder block and mating cylinder
head 0.2 mm at maximum.
Cylinder block height (when new):
243.5 mm <4G92>
263.5 mm <4G93>
286.7 mm <4G94>
(3) Check the cylinder walls for scratches and seizure. If
defects are evident, correct (bored to oversize) or replace.
(4) Using a cylinder gauge, measure the cylinder bore and
cylindricity. If worn badly, correct the cylinder to an
oversize and replace the piston and piston rings. Measure
at the points shown in illustration.
Standard value:
Cylinder inner diameter:
4G92, 4G93 81.00 – 81.03 mm
4G94 81.50 – 81.53 mm
Out-of-roundness and taper of cylinder bore: 0.01
mm or less
BORING CYLINDER
(1) Oversize pistons to be used should be determined on
the basis of the largest bore cylinder.
Piston size identification
Size Identification mark
0.50 mm O.S. 0.50
1.00 mm O.S. 1.00
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
(honing margin)
(4) Bore all cylinders to the calculated boring finish dimension.
PWEE9502-I
E
Mar. 2001 Mitsubishi Motors Corporation Revised
A
B
12 mm
Centre
Bottom
Piston O.D.
Thrust
direction