Piston, Connecting Rod, and Bearing Cleaning and
Inspection
Visual Inspection And Cleaning Procedure
Connecting Rod
|
Warning:
Wear safety glasses when using compressed air in
order to prevent eye injury. |
1. |
Clean the connecting rods (1)
in solvent and dry with compressed air. |
2. |
Inspect the connecting rod for
the following: |
|
• |
Signs of being twisted, bent,
nicked or cracked. |
|
• |
Scratches or abrasion on the
connecting rod bearing seating surfaces. |
Piston
1. |
Clean the piston with a
cleaning solvent. DO NOT wire brush any parts of the piston.
|
2. |
Clean the piston ring
grooves. |
3. |
Inspect the piston on the
following: |
|
• |
Cracked ring lands, skirts or
pin bosses |
|
• |
Eroded areas on the top of the
piston (1) |
|
• |
Scuffed or damaged skirts
(2) |
|
• |
Worn piston pin bores
(3) |
4. |
If there is any excessive
wear, replace the piston. |
5. |
Measure the clearance between
piston pin and piston bore. Use the following procedure:
|
Piston And Connecting Rod Measurement Procedure
Piston Pin To Connecting Rod Bore And Piston Bore
Clearance
1. |
Measure clearance between
piston pin and connecting rod bore. Use the following
procedure: |
|
1.1 |
Measure the piston pin outside
diameter. |
|
1.2 |
Measure the connecting rod
bore diameter. |
|
1.3 |
Substract the piston ring
diameter from the connecting rod diameter. |
|
1.4 |
The clearance should be
0.008 mm - 0.020 mm (0.0003 in - 0.0007 in)
. |
2. |
If there is excessive
clearance, replace the piston pin. |
3. |
If there is still excessive
clearance, replace the connecting rod. |
|
3.1 |
Measure the piston pin outside
diameter. |
|
3.2 |
Measure the piston bore
diameter. |
|
3.3 |
Substract the piston pin
diameter from the piston bore diameter. |
|
3.4 |
The clearance should be
0.004 mm - 0.017 mm (0.0002 in - 0.0006 in)
. |
4. |
If there is excessive
clearance, replace the piston pin. |
5. |
If there is still excessive
clearance, replace the piston. |
Piston Ring Clearance
1. |
Install the piston rings to
the cylinder as shown (1) and measure the piston ring end gap.
Compare the measurements with those provided below: |
|
• |
The upper compression ring end
gap should be 0.200 mm - 0.300 mm (0.0078 in - 0.0118
in) . |
|
• |
The lower compression ring end
gap should be 0.200 mm - 0.300 mm (0.0078 in - 0.0188
in) . |
|
• |
The oil ring end gap should be
0.200 mm - 0.400 mm (0.0078 in - 0.0157 in)
. |
2. |
If the clearance is greater
than the provided specifications, the piston rings must be
replaced. |
3. |
Measure the piston ring side
clearance as shown (1). Compare the measurements with those
provided below: |
|
• |
The upper compression ring
side clearance should be 0.090 mm - 0.122 mm (0.0035 in -
0.0048 in) . |
|
• |
The lower compression ring
side clearance should be 0.040 mm - 0.090 mm (0.0015 in -
0.0035 in) . |
|
• |
The oil ring side clearance
should be 0.025 mm - 0.065 mm (0.0009 in - 0.0025
in) . |
4. |
If the clearance is greater
than the provided specifications, replace the piston rings.
|
5. |
If the clearance is still to
great, replace the pistons. |
Connecting Rod Bearing Clearance (With Micrometer Gauge
Internal Measuring Device)
1. |
Install the connecting
bearings and the connecting rod bearing caps. |
2. |
Tighten the connecting rod
bearing cap bolts in the following sequence: |
|
Note: The old bolts can be
reused for the measuring procedure.
|
|
2.1 |
Tighten the connecting rod
bearing cap bolts to 25N·m (18 lb ft)
. |
|
2.2 |
Tighten the bolts to an
additional 100° . |
|
2.3 |
Tighten the bolts to an
additional 15° . |
3. |
Measure the connecting rod
bearing diameters at 3 points as shown (1). Use a internal
measuring device. |
4. |
Calculate the average
connecting rod inner diameter. |
|
Formula: 1. result + 2. result + 3. result / 3 |
5. |
Measure the connecting rod
journal diameter at 2 points between (1) and (3) and between (2)
and (4). Use a micrometer gauge. |
6. |
Calculate the average
connecting rod journal diameter. |
|
Formula: 1. result + 2. result / 2. |
7. |
Substract the average
connecting rod journal diameter from the average connecting rod
bearing diameter in order to determine the connecting rod bearing
clearance. |
|
The clearance should be 0.025 mm - 0.058 mm (0.0010 in
- 0.0023 in) . |
|