Lube Systems And Crankcase Ventilation Flashcards
Good quality oil will?
Reduce wear, Clean, Absorb heat, Act as a sealant
Viscosity?
is a measure of a resistance to flow. High viscosity oil flows slower, low viscosity flows quicker
What happens to oil viscosity when the temperature increases?
Increase in viscosity when cooled
Decrease in viscosity when heated
What is viscosity index?
Refers to the rate that oil will change viscosity as the temperature changes.
High vs low viscosity index?
High - Small changes in viscosity through temp changes
Low - large changes in viscosity through temp changes
What is pour point?
The lowest temp that oil will flow from a full test tube on a 45* angle
What is purpose of oil detergents?
Prevent deposits from forming on internal engine parts?
What is purpose of dispersants?
Keep the deposits suspended in the oil
Function of oxidation inhibitors?
Prevent the oil from absorbing excess oxygen, this will reduce the build up of varnish and sludge in the oil
Function of Anti-rust additives?
To help maintain an oil film on exposed internal engine parts when the engine is not running. This feature is sometimes referred to as oiliness.
Oil is classified according to?
Standards set by the American petroleum institute (API)
Oil SI classification?
Refers to oils used in spark ignition engines
Oil CI classification?
Describes oil used in compression ignition engines
To obtain the most reliable result, the oil sample should be gathered?
When oil is hot and particles are still in suspension, and the sample is taken during midstream of the oil drain
What are the 2 main purposes of an oil analysis?
Determine the suitability of the oil for further use.
Determine if there are any existing internal problems.
What are the 2 types of lubrication systems?
Full pressure - all oil is delivered through pump pressure
Splash and pressure - Combination of splash and pressure lubrication used
What is the function of the oil pan?
It is used to store and cool the supply of lubricating oil
Wet sump vs Dry sump
Wet sump - Wet the pan and lower crankcase are used for the storage of oil
Dry sump - the engine oil supply is stored in a remote location
To allow more heat transfer oil pans may be made of?
Sheet steel or aluminum
What are the two most common designs of oil pumps?
External and rotor type
What is the purpose of the oil pressure regulating valve?
Maintain the system oil pressure within normal operating limits.
What are the two main types of oil coolers?
Oil to air
Oil to coolant
What is purpose of oil cooler bypass valve?
Allow oil to bypass the cooler when trying to get the engine warm at start up
Two types of oil filters? Function?
Full flow - Filter oil going to block
Bypass - Filters 5-10% of pump oil and return it to the pan
What is the purpose of a crankcase ventilation system?
Removes combustion gases and water vapours from the crankcase, to avoid over pressurizing
What are the two styles of crankcase ventilation?
Road draft - expelled towards the ground
Positive crankcase ventilation - Vented back into the intake
Oil pump components should be inspected for?
Score marks, Worn shafts, cracked housings, teeth pits, radial and axial play
Amount of oil consumed during operation can be affected by?
Age and condition of engine, Type and design, Type of service, Operating condition, Internal problems, External factors
What can occur if the oil level is too high?
Oil foaming
What are the three main oil indicators used on the majority of engines?
Level indicators
Pressure indicators
Temperature indicators
What can happen if the crankcase were to become over pressurized?
Oil leakage past seals and gaskets could occur. The oil may become contaminated with acid, water and fuel buildup.
