Engine Lubrication Flashcards
A RECIPROCATING ENGINE IS FOUND TO HAVE EXCESSIVE OIL CONSUMPTION WITHOUT EVIDENCE OF ANY OIL LEAKS. WHAT IS THE LIKELY CAUSE?
The piston rings are worn or broken
WHAT ARE THE FUNCTIONS OF LUBRICATING OIL IN RECIPROCATING ENGINES?
To reduce friction between moving parts and remove heat
NAME TWO IMPORTANT CHARACTERISTICS OF AIRCRAFT ENGINE OIL
1) Light enough to circulate freely
2) Heavy enough to provide the proper film at operating temperatures
WHAT COULD HAPPEN TO AN OIL THAT IS TOO LOW IN VISCOSITY AT NORMAL ENGINE OPERATING
TEMPERATURES
The oil film between moving parts is easily broken, resulting in premature wear
WHAT ARE SOME OF THE FACTORS THAT MUST BE CONSIDERED BY AN ENGINE MANUFACTURER IN DETERMINING THE PROPER GRADE OIL FOR A PARTICULAR ENGINE
1) Operating load
2) Temperature
3) Rotational speed
WHY DO AIRCRAFT RECIPROCATING ENGINE USE A RELATIVELY HIGH VISCOSITY OIL?
Large operating clearances
Operate at high temperatures & pressures
NAME SOME OIL CONTAMINANTS
1) Metal particles
2) Dirt
3) Carbon
4) Moisture
5) Acids
What is a possible indication of low oil pressure together with high oil temperature?
Low or inadequate oil supply
IN ASHLESS DISPERSANT (AD) OILS, WHAT FUNCTION DOES THE DISPERSANT PERFORM
Causes sludge-forming materials to repel each other and suspend until they can be trapped by the oil filter or drained. Keeping the inside of the engine clean
WHY DO OIL RESERVOIRS HAVE EXPANSION SPACE
To provide for:
1) Oil foaming
2) Thermal expansion
3) Air in the return oil
WHAT COULD CAUSE OIL FOAMING?
1) Diluted oil
2) Contaminated oil
3) Oil level being too high
WHAT CONTOLS OIL PRESSURE IN A GEAR-TYPE OIL PRESSURE PUMP?
The oil pressure relief valve
WHAT FUNCTION DOES AN OIL COOLER BYPASS VALVE PERFORM?
Directs oil through or around the cooler to maintain proper oil temperature
WHAT COULD BE A POSSIBLE INDICATION IF THE OIL COOLER PASSAGE BECOMES OBSTRUCTED?
High oil temperature
WHERE IS THE OIL TEMPERATURE BULB USUALLY LOCATED?
The engine oil inlet
WHAT DOES THE PRESENCE OF METAL PARTICLES IN AN ENGINE OIL FILTER INDICATE?
Depending on the type and size of the metal particles, this usually indicates abnormal wear/internal failure
WHAT SHOULD BE DONE IF METAL PARTICLES ARE FOUND IN AN ENGINE OIL FILTER?
Follow engine manufacturer’s maintenance instruction
WHERE IS THE MOST CRITICAL POINT OF LUBRICATION IN A GAS TURBINE ENGINE?
The turbine bearing
WHAT TYPE OF OIL IS USED IN A TURBINE ENGINE OIL SYSTEM?
Synthetic oil
WHERE ARE OIL SCREENS OR FILTERS MOST LIKELY LOCATED IN A TURBINE ENGINE OIL SYSTEM?
1) Oil pressure system
2) Scavenge system
3) Just before the oil jet
NAME TWO TYPES OF TURBINE ENGINE OIL COOLERS
1) Air cooled
2) Fuel cooled
WHAT COULD HAPPEN TO AN OIL THAT IS TOO LOW IN VISCOSITY AT NORMAL OPERATING TEMPERATURES
Become so thin the oil film between moving parts is easily broken resulting in premature wear.
