Inspection Of Piston And Connecting Rod Assemblies

1. CLEAN PISTON

(a) Using a gasket scraper, remove the carbon from the piston top.

(b) Using a groove cleaning tool or broken ring, clean the ring grooves.

<c) Using a soft brush and solvent, thoroughly clean the piston.

NOTICE: Do not damage the piston.

2. INSPECT PISTON DIAMETER AND OIL CLEARANCE

(a) Using a micrometer, measure the piston diameter at a right angle to the piston pin hole center line, 22 mm (0.87 in.) from the piston head.

7M-GE

Front Mark if

\\

— Front jW

>)

Piston y^Sr—

yjj

Size Mark

(0. 1,2. 3 or 4) \---

CMS JAA

HINT: There are five sizes of standard piston diameter, marked "0"1", "2", "3" and "4" accordingly. The mark is stamped on the piston as shown in the illustration.

7M-GTE

Front Mark fys

Front \V

coOoj

Size Mark

(0, 1.2, 3 or 4)

IM6166

Piston diameter: STD size 7M-GE

7M-GTE

Mark

"0"

82.900

82.910 mm

(3.2638

3.2642 in.)

Mark

82.911

82.920 mm

(3.2642

3.2646 in.)

Mark

» #2 * *

82.921

82.930 mm

(3.2646

3.2650 in.)

Mark

"3"

82.931

82.940 mm

(3.2650

3.2653 in.)

Mark

82.941

82.950 mm

(3.2654

3.2657 in.)

Mark

"0"

82.910

82.920 mm

(3.2642

3.2646 in.)

Mark

tt <| t»

82.921

82.930 mm

(3.2646

3.2650 in.)

Mark

82.931

82.940 mm

(3.2650

3.2653 in.)

Mark

"3"

82.941

82.950 mm

(3.2654

3.2657 in.)

Mark

"4"

82.951

82.960 mm

(3.2658

(b) Measure the cylinder bore diameter in thrust directions. (See page EM-74)

(c) Subtract the piston diameter measurement from the cylinder bore diameter measurement.

Standard oil clearance: 7M-GE 0.08 - 0.10 mm (0.0031 - 0.0039 in.) 7M-GTE 0.07 - 0.09 mm (0.0028 - 0.0035 in.)

Maximum oil clearance: 0.13 mm (0.0051 in.)

If the oil clearance is greater than maximum, replace the piston. If necessary, rebore all six cylinders and replace all six pistons. If necessary, replace the cylinder block.

HINT: (Use cylinder block sub-assembly) When installing a standard piston, install one with the same mark as the standard bore diameter mark on the cylinder block.

Piston Ring Inspect Clearance

3. INSPECT CLEARANCE BETWEEN WALL OF RING GROOVE AND NEW PISTON RING

Using a thickness gauge, measure the clearance between new piston ring and the wall of the piston ring groove.

Ring groove clearance: 0.0 \

No.1 0.03 - 0.07 mm (0.0012 - 0.0028 in.) No.2 0.02 - 0.06 mm (0.0008 - 0.0024 in.)

If the clearance is not within specification, replace the piston.

7M-GE

Piston Clearance 7mgte

Limn

7M-GTE

Limit

4. INSPECT PISTON RING END GAP

(a) Insert the piston ring into the cylinder.

<b) Using a piston, push the ring a little beyond the bottom of the ring travel.

(110 mm (4.33 in.) from the top surface of cylinder block)

(c) Using a thickness gauge, measure the end gap.

Ring end gap:

Limn

Limit

Limit

7M-GE

7M-GTE

If the diameter is geater than maximum, rebore all six cylinders, or replace the cylinder block.

5. CHECK PISTON PIN FIT

At 60°C (140°F) you should be able to push the pin into the piston with your thumb.

If the pin can be installed at a lower temperature, replace the piston.

Connecting Rod Aligner

6. INSPECT CONNECTING ROD

(a) Using a rod aligner and thickness gauge, check the connecting rod alignment. • Check for bend.

Maximum bend:

If bend is greater than maximum, replace the connecting rod assembly.

Maximum twist:

If twist is greater than maximum, replace the connecting rod assembly.

Connecting Rod Aligner
CM0269 f MO290

(b) Inspect the oil clearance between the rod bushing and piston pin.

• Using a caliper gauge, measure the inside diameter of the connecting rod bushing.

Bushing inside diameter: 22.005 - 22.017 mm

• Using a micrometer, measure the piston pin diameter.

Piston pin diameter: 21.996 — 22.009 mm

♦ Subtract the piston pin diameter measurement from the bushing inside diameter measurement. Standard oil clearance: 0.005 - 0.011 mm

(0.0002 - 0.0004 in.) Maximum oil clearance: 0.02 mm (0.0008 in.)

If the oil clearance is greater than maximum, replace the bushing. If necessary, replace the piston and piston pin assembly.

7. IF NECESSARY, REPLACE CONNECTING ROD BUSHING

(a) Using SST and a press, press out the bushing. SST 09222-30010

(b) Align the oil holes of a new bushing and connecting rod.

(c) Using SST and a press, press in the bushing. SST 09222-30010

Piston Rod Assembly Inspection

(d) Using a pin hole grinder, hone the bushing to obtain the specified clearance between the bushing and piston pin.

(e) Check the piston pin fit at normal room temperature. Coat the piston pin with engine oil and push it into the connecting rod with your thumb.

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