Boring Cylinders; Oil Pressure Switch Installation - Mitsubishi 4G1 Series General Information Manual

11A-12-4
4G1 ENGINE (E - W) -
12
mm
Piston O. D.
Apply sealant
E
E
Mitsubishi Motors Corporation
Mitsubishi Motors Corporation
6EN0553
Thrust
direction
6EN0554
MD9988054
Nov. 1995
Dec. 1998
Crankshaft and Cylinder Block
(4) Using a cylinder gauge, measure each cylinder's bore
and cylindricity. If any cylinder is severely worn, bore
all the cylinders to oversize and replace the piston and
piston rings accordingly. Take measurements at the points
shown.
Standard value:
Cylinder bore:
4G13 engine: 71.0 mm
4G15 engine: 75.5 mm
4G18 engine: 76.0 mm
Cylindricity: 0.01 mm or less

3. BORING CYLINDERS

(1) Oversize pistons to be used should be determined on
the basis of the cylinder with the largest bore.
(2) Oversize pistons are available with the following oversize
dimensions: 0.25 mm, 0.50 mm, and 1.00 mm. Measure
the diameter of the piston to be used. Boring must be
carried out such that the piston-to-cylinder clearance
complies with the standard value. The piston's diameter
should be measured at the points shown.
(3) Calculate the boring finish dimension based on the piston
diameter dimension.
D [Boring finish
[piston-to-cylinder clearance (0.02 – 0.04 mm)] -
[honing margin (0.02 mm)]
(4) Bore each cylinder to the calculated boring finish
dimension.
Caution
To prevent distortion caused by heat increases during
boring bore the cylinders in the following order: No.
2, No. 4, No. 1, No. 3.
(5) Hone the cylinders to the final finish dimension (piston
O. D. + piston-to-cylinder clearance).
(6) Check the clearance between the pistons and cylinders.
Standard value: 0.02 - 0.04 mm
INSTALLATION SERVICE POINTS
"AA OIL PRESSURE SWITCH INSTALLATION
(1) Apply the specified sealant to the thread, then fit the
oil pressure switch using the special tool shown in the
illustration.
Specified sealant:
3M ATD Part No. 8660 or equivalent
Caution
1. Apply sealant such that none is squeezed out
past end of the thread.
2. Do not over-tighten the oil pressure switch.
PWEE9520
PWEE9520-A
dimension] = [piston O.D.] +
Revised