Nelson conducted a compression test on a four-cylinder petrol engine and found that the engine has low compression in one of the cylinders - NSC Mechanical Technology Automotive - Question 5 - 2019 - Paper 1
Question 5
Nelson conducted a compression test on a four-cylinder petrol engine and found that the engine has low compression in one of the cylinders.
5.1.1 Name TWO types of ... show full transcript
Worked Solution & Example Answer:Nelson conducted a compression test on a four-cylinder petrol engine and found that the engine has low compression in one of the cylinders - NSC Mechanical Technology Automotive - Question 5 - 2019 - Paper 1
Step 1
5.1.1 Name TWO types of compression tests Nelson can perform on the engine.
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Answer
Wet test
Dry test
Step 2
5.1.2 Give TWO possible reasons for low compression in the cylinder.
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Answer
Worn piston rings
Leaking cylinder head gasket
Step 3
5.2 Explain how static imbalance of a wheel is corrected using a wheel balancing.
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Answer
A small mass or weight is applied to the wheel rim diametrically opposite the heavy spot until the wheel is in balance.
Step 4
5.4 Give TWO reasons for a high CO reading.
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Answer
Too rich mixture
Ignition misfire
Step 5
5.5.1 Identify the wheel alignment equipment shown in FIGURE 5.5.
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Answer
The equipment shown is a bubble gauge.
Step 6
5.5.2 Explain how to take a caster reading on the wheels of a motor vehicle using the wheel alignment equipment in FIGURE 5.5.
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Answer
Ensure that the wheels are straightened and the turntables are on zero.
Fit the gauge to the centre of the wheel.
Turn the front of the wheel 20° inwards.
Zero the castor scale.
Turn the wheel through 40° in the opposite direction.
Take the reading on the castor scale.
Do the same for the other wheel.
Step 7
5.6 Which information is required by the diagnostic scanner before a diagnostic test can be conducted on an internal combustion engine?
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