Lubrication Systems Flashcards
Uses of Oil Lubrication System
Lubricates Protects Cools Seals Cleans Lengthening the life of the engine Provides oil for the variable pitch propellor system
Oil Properties
Viscosity for the operating temperatures (use the correct grade of oil)
Must have a high flash and fire point (will not vaporise or catch fire)
Must be chemically stable
Dry Sump
Keeps oil in an external tank
Uses a scavenge pump
Tigermoth (due to in-line inverted engine)
Contains emergency oil to feather the propellor in case of engine failure
Pressure Relief Valve
Used to prevent high pressures and excess oil entering the engine
Allows excess oil to return to the pump inlet
Oil Cooler
Measures in degrees Fahrenheit
A set of cooling baffles
Has a bypass valve when oil is already cool (uses a thermostat)
Oil Temperature
Measured in degrees Fahrenheit
Normal temperature in the sump is approx 180 degrees Fahrenheit
Temperature near cylinder heads is close to 212 degrees Fahrenheit to evaporate any water, fuel, etc.
Oil Types
Ashless Dispersant Oil
Mineral Oil
Synthetic Oil
Ashless Dispersant Oil
Suspends contaminants so they can be filtered out
Leave no metallic ash when burnt, reducing the risk of spark plug fouling and pre-ignition
Mineral Oil
More abrasive as no dispersant
Good for use in a new engine creating small grooves in the cylinder walls in which lubricating oil can sit
Synthetic Oil
Has a high viscosity index and can be used over a very large temperature range
Wet Sump
Oil is stored in the sump in the lower part of the engine casing
Oil Pump
Usually engine-driven
Pumps more oil than the engine requires
Oil Filter
Remove foreign matter from the system
Contains a bypass valve allowing oil to pass a blocked filter
Oil Pressure Gauge
Indicates the pressure provided by the pump
Situated just after the oil pump
Oil Temperature Gauge
A probe sensing the temperature of the oil after it has passed through the cooler
