A
B
12 mm
Centre
Bottom
Thrust direction
Piston O.D.
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):
243.5mm <4G92>
263.5mm <4G93>
286.7mm <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
4G9481.50 – 81.53 mm
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.
E Mitsubishi Motors CorporationMar.2001 | Revised |