Mitsubishi Grandis. Manual - part 665

PISTON AND CONNECTING ROD

ENGINE OVERHAUL

11B-55

1. Mark the cylinder number on the side of the 

connecting rod big end for correct reassembly.

2. Keep the removed connecting rods, caps, and 

bearings in that order according to the cylinder 
number.

<<B>> PISTON PIN REMOVAL

The special tool Piston pin setting tool (MD998780), 
consists of the elements shown in the drawing.

1. Insert the tool element, Push rod, into the piston 

from the front mark side, then attach the element, 
Guide C, to the push rod.

2. Place the piston and connecting rod assembly on 

the element, Base, with the front mark facing up.

3. Use a press to remove the piston pin.

NOTE: Keep the disassembled pistons, piston 
pins and connecting rods cylinder by cylinder.

INSTALLATION SERVICE POINTS

>>A<< PISTON PIN INSTALLATION

1. When replacing a piston, check the cylinder bore 

size mark stamped at the indicated location on the 
cylinder block and select an appropriate 
replacement piston using the following table.

AK301562

Push 
rod

Guide B

Guide C

Guide A: 17.9 mm

Guide A: 18.9 mm

Guide A: 20.9 mm

Guide A: 21.9 mm

Base

AB

AK202781

Push rod

Front mark

Base

Front 
mark

Guide C

AC

AK301530

No.4

No.3

No.1

No.2

Timing belt side

AD

Crankshaft 
bore size mark

PISTON AND CONNECTING ROD

ENGINE OVERHAUL

11B-56

NOTE: The piston size mark is located on the 
piston top surface.

2. Measure the following dimensions:

A: Piston pin insertion hole length
B: Distance between piston bosses
C: Piston pin length
D: Connecting rod small end width

3. Obtain dimension L from the measurements using 

the following formula.
L = [(A-C) 

− (B-D)] ÷ 2

4. Insert the tool element, Push rod, into the piston 

pin and attach the element, Guide A, to the push 
rod end.

5. Assemble the connecting rod with the piston with 

their front marks facing in the same direction.

6. Apply engine oil to the outside surface of the 

piston pin.

7. Insert the assembly of piston pin, Push rod, and 

Guide A (put together in step 4.) into the piston 
holes from the front mark side.

8. Screw the tool element, Guide B, into the tool 

element, Guide A until the gap between both the 
elements is equal to the dimension L (obtained in 
step 3.) plus 3 mm.

9. Place the piston and connecting rod assembly 

onto the element, Piston setting base, with the 
front marks facing up.

10.Install the piston pin using a press. If the required 

press force is less than the standard value, 
replace the piston and piston pin assembly or the 
connecting rod, or both.

Standard value: 7,350 

− 17,200 N 

Cylinder bore size mark

Piston size mark

I

A

II

No mark

III

C

AK202784

Connecting rod

Piston

Piston pin

D

C

B

A

AE

AK301480

3 mm + L

Guide A

Guide B

AC

AK202782

Push rod

Front mark

Piston pin

Base

Front 
mark

Guide B

Guide A

AB

PISTON AND CONNECTING ROD

ENGINE OVERHAUL

11B-57

11.Check that the piston moves smoothly.

AK301796

PISTON AND CONNECTING ROD

ENGINE OVERHAUL

11B-58

>>B<< OIL RING INSTALLATION

1. Fit the oil ring spacer into the piston ring groove.

CAUTION

Do not use a piston ring expander when 
installing side rail.
2. Install the upper side rail.

To install the side rail, first fit one end of the rail 
into the piston groove, then press the remaining 
portion into position by hand. See illustration.
NOTE: The side rails and spacer may be installed 
in either direction.
NOTE: New spacers and side rails are colored for 
identification of their sizes.

3. Install the lower side rail in the same manner as 

described in step 2.

4. Make sure that the side rails move smoothly in 

both directions.

>>C<< PISTON RING NUMBER 2/PISTON 
RING NUMBER 1 INSTALLATION

1. Using the piston ring expander, fit number 2 into 

the number 2 groove of piston.
NOTE: Install piston rings with identification mark 
facing up, to the piston crown side.

2. Install the number 1 piston ring in the same 

manner as step 1.

Identification mark:

Number 1 ring: 1R
Number 2 ring: 2R
NOTE: Confirm the profile for No.1 and No.2 
piston rings carefully. Install them correctly by 
careful attention to the direction of top and 
bottom.
NOTE: The identification mark and the size mark 
are stamped on the upper plane of the piston ring 
(piston top side).

3. To prevent wrong installation, check the 

identification mark of each piston ring. The 
identification mark is stamped near the ring gap.

Size

Identification color

Standard

None

0.50 mm oversize 
diameter

Red

AK300190

Side rail end

AD

AK304597AB

Upper
side rail

Spacer

Lower 
side rail

Size

Size mark

Standard

None

0.50 mm oversize 
diameter

50

AK300191

Piston ring
expander

AD

AK301452AD

No.1

No.2