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WorksheetsSI 1191A - Cylinder Compression
Total questions: 10
Worksheet time: 5mins
What is the purpose of the differential compression test?
To measure oil pressure
To measure cylinder static leak rate
To check magneto timing
To balance the propeller
At what piston position should the differential compression test be performed?
Bottom dead center of the power stroke
Top dead center of the compression stroke
Middle of the intake stroke
Bottom dead center of the exhaust stroke
What is the correct air supply pressure for the test?
100 psi
60 psi
80 psi
50 psi
What is the critical orifice size specified for Textron Lycoming engines?
.020 in. diameter
.040 in. diameter
.060 in. diameter
.080 in. diameter
What does air discharged from the exhaust system during the test indicate?
Intake valve leakage
Exhaust valve leakage
Piston ring leakage
Normal operation
If all cylinder pressures are equal and above 70 psi, the engine is:
In need of overhaul
Operating satisfactorily
Unsafe to operate
Losing oil rapidly
What does air discharged from the breather or oil filler tube indicate?
Exhaust valve leakage
Intake valve leakage
Piston and ring leakage
Head gasket failure
What should be done if cylinder pressure is below 60 psi?
Nothing, it is normal
Immediately remove and overhaul the cylinder
Recheck in 10 hours of operation
Replace the spark plugs
What precaution must be taken before attaching the compression tester?
Warm the engine to high temperature
Check that the fuel tanks are full
Ensure the air supply regulator is not excessive
Disconnect the battery
A pressure difference of more than 15 psi between cylinders usually indicates:
Spark plug fouling
Magneto timing issue
A need for further investigation
A normal condition
