Chevrolet Sonic Repair Manual: Piston, Connecting Rod, and Bearing Cleaning and Inspection
Special Tools
EN-470-B Angular Torque Wrench
For equivalent regional tools, refer to Special Tools.
- Visual Inspection And Cleaning Procedure
- Connecting Rod
Warning:
Wear safety glasses when using compressed air in
order to prevent eye injury.
- Clean the connecting rods in solvent and dry with compressed air.
- 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
- Clean the piston with a cleaning solvent. DO NOT wire brush any parts
of the piston.
- Clean the piston ring grooves.
- Inspect the piston on the following:
- Cracked ring lands, skirts or pin bosses
- Ring grooves for nicks
- Eroded areas on the top of the piston (1)
- Scuffed or damaged skirts (2)
- Worn piston pin bores (3)
- If there is any excessive wear, replace the piston.
- Measure the clearance between piston pin and piston bore.
- Piston And Connecting Rod Measurement Procedure
- Piston Ring Clearance
__
- 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 0.4?E.6 mm (0.0157?E.0236 in).
- The lower compression ring end gap should be 0.4?E.6 mm (0.0157?E.0236 in).
- The oil ring end gap should be 0.2?E.9 mm (0.0079?E.0354 in).
- If the clearance is greater than the provided specifications, the piston
rings must be replaced.
- Measure the piston ring side clearance as shown (1). Compare the measurements
with those provided below:
- The upper compression ring side clearance should be 0.025?E.07 mm (0.001?E.0028 in).
- The lower compression ring side clearance should be 0.025?E.07 mm (0.001?E.0028 in).
- The oil ring side clearance should be 0.04?E.12 mm (0.0016?E.0047 in).
- If the clearance is greater than the provided specifications, replace the
piston rings.
- If the clearance is still to great, replace the pistons.
Connecting
Rod Bearing Clearance (With Micrometer Gauge Internal Measuring Device)
- Install the connecting bearings and the connecting rod bearing caps.
- Tighten the connecting rod bearing cap bolts in the following sequence:
Caution:
Refer to Fastener Caution
Note:
The old bolts can be reused for the measuring procedure.
- Tighten the connecting rod bearing cap bolts to 10 Y (89 lb in)
.
- Tighten the bolts to an additional 60 degrees using EN-470-B
wrench.
- Tighten the bolts to an additional 15 degrees using EN-470-B
wrench.
- Measure the connecting rod bearing diameters at 3 points as shown (1).
Use a internal measuring device.
- Calculate the average connecting rod inner diameter.
Formula: 1. result + 2. result + 3. result / 3
- Measure the connecting rod journal diameter at 2 points between (1)
and (3) and between (2) and (4). Use a micrometer gauge.
- Calculate the average connecting rod journal diameter.
Formula: 1. result + 2. result / 2.
- 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 0.013?E.061 mm (0.0005?E.0024 in)
.
Remove the piston with connection rod. Refer to Piston, Connecting Rod,
and Bearing Removal.
Note: Note installation position of the piston in respect of the
connection rod.
...
Special Tools
EN-470-B Angular Torque Wrench
For equivalent regional tools, refer to Special Tools.
Adjust the piston ring joints as follows:
Upper compression ring (1).
...
Other materials:
Starting Procedure
1. With your foot off the accelerator pedal, turn the ignition to START. When
the engine cranks, let go of the key. The idle speed will go down as the engine
gets warm.
The vehicle has a Computer-Controlled Cranking System. It assists in starting
the engine and protects components. If the ign ...
Environmental Fallout (Acid Rain)
Caution: Refer to Clearcoat/Ultraviolet Screeners Caution.
Note: Always refer to the manufacturer's packaged instructions for
the detailed procedures of materials used for compounding and/or polishing.
Since the severity of the condition varies from area to area, proper diagno ...
Sunroof Window Height and Opening Fit Adjustment
Note: Correct adjustment cannot be achieved if the sunroof window
is closed from vent position.
Cycle the sunroof window from full open to closed position.
.,
Note: Do Not remove or lower headliner to access sunroof window
screws.
Loosen the adjusting screws on ...
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