Diesel Engine Design
Piston Ring face material used on compression rings to aid in upper cylinder wall lubrication
A: Steel
B: Molybdenum
C: Cast Iron
D: Chrome
B: Molybdenum
In a four-stroke diesel engine, during which stroke does air charge the cylinder?
A: Exhaust
B: Compression
C: Power
D: Intake
D: Intake
The “30” in 10W-30 engine oil stands for which of the following?
A: Viscosity at 0°F (-18°C)
B: Viscosity at 212°F (100°C)
C: The thickness of the oil when cold
D: Multiple viscosities
B: Viscosity at 212°F (100°C)
Coolant in an engine is usually which of the following colors:
A: Blue
B: Green
C: Red
D: Any of the above, depending on the type of anti-freeze
D: Any of the above, depending on the type of anti-freeze
Compression gases that leak past piston rings and enters the crankcase is referred to as:
A: Piston slap
B: Blow-by
C: Compression pressure
D: Soot loading
B: Blow-by
What is the purpose of frost plugs or core plugs in engine blocks?
A: To prevent block damage if it freezes
B: To facilitate the cleaning out of sand during casting
C: To provide an opening for cooling system accessories like block heaters
D: To provide inspection covers to check for block porosity
B: To facilitate cleaning out of sand during casting of the block
The stroke length of an engine can only be changed by changing:
A: The cylinder bore
B: The valve timing
C: The length of the crankshaft throw
D: The length of the connecting rod
C: The length of the crankshaft throw
Maximum lubrication oil temperate should not exceed:
A: 200°F (93°C)
B: 215°F (102°C)
C: 235°F (113°C)
D: 250°F (121°C)
D: 250°F (121°C)
A technician notices a drop in the coolant level in the surge tank or coolant overflow reservoir after the engine cools. The most likely cause is?
A: Internal leak in the engine
B: A bad pressure cap
C: A bad thermostat
D: The drop in the level is normal
D: The drop in the level is normal
A: Technician A
B: Technician B
C: Both Technicians
D: Neither Technicians
A: Technician A
The lightest, strongest, quietest engine blocks are made from this
A: Compacted Graphite Iron (CGI)
B: Dry sleeve blocks
C: Parent bore blocks
D: Aluminum
A: Compacted Graphite Iron (CGI)
When installing piston rings it is best to:
A: Space the ring gaps so that they are all in line
B: Space the ring gaps 120° apart from each other
C: Stretch them out so that they are easier to install
D: None of the above
B: Space the ring gaps 120° apart from each other
Oil lubrication filters main purpose is to:
A: Regulate oil pressure
B: Remove contaminates from the oil
C: Cool lubrication oil
D: All of the above
B: Remove contaminates from the oil
A diesel engine fails to reach operating temperature. Which of the following is the most likely cause?
A: Stuck open thermostat
B: Stuck closed thermostat
C: Restricted radiator
D: Restricted charge air cooler (CAC)
A: Stuck open thermostat
Technician A says that cross-hatch in a cylinder wall is needed to retain engine oil and promote gas-tight piston ring seals. Technician B says that cross-hatch in a cylinder wall is used to keep oil from sticking to cylinder walls. Who is correct?
A: Technician A
B: Technician B
C: Both Technicians
D: Neither Technicians
A: Technician A
Crankshaft counterweights are used to reduce engine vibration caused by which of the following?
A: Angular velocity changes of the crankshaft
B: Uneven firing impulses
C: Torsional vibration
D: The inertia of the piston/connecting rod assembly
D: The inertia of the piston/connecting rod assembly
Which piston ring will cause excessive oil consumption if it is installed upside down in a diesel engine?
A: The intermediate ring
B: The compression ring
C: The oil control ring
D: It doesn’t matter which way the piston matter which way the piston rings are installed
A: The intermediate ring
Which of the following is the most likely cause of excessively high oil pressure?
A: A defective pressure regulating valve
B: A spun main bearing
C: A restricted oil gallery
D: A plug oil filter
A: A defective pressure regulating valve
If a upper radiator hose collapses after an engine cools, what is the most likely cause?
A: Restricted radiator core
B: A defective pressure relief valve
C: A defective pressure cap vacuum valve
D: Overconcentrated anti-freeze-to-water solution
C: A defective pressure cap vacuum valve
Cylinder head gaskets are made from which of the following?
A: Multi-layer steel gaskets
B: Cork gaskets
C: RTV High temperature gasket maker
D: A or C
A: Multi-layer steel gaskets
Technician A says that the cam gear rotates two times faster than the crank gear. Technician B says that the cam gear rotates at half the engine speed. Who is correct?
A: Technician A
B: Technician B
C: Both Technicians
D: Neither Technicians
B: Technician B
Which position are the engine valves in during the power stroke?
A: Intake valve is closed, exhaust valve is open
B: Intake valve is open, while exhaust valve is closed
C: Intake and exhaust valves are both closed
D: Intake and exhaust valves are both open
C: Intake and exhaust valves are both closed
Which of the following is the most likely cause of excessively low oil pressure?
A: Engine oil leaks
B: Fuel in the oil
C: Worn out rod and main bearings
D: Hot engine oil
C: Worn out rod and main bearings
Technician A says that less than 4 ounces of ingested Ethylene glycol is enough to kill a 150lb human. Technician B says that Propylene glycol is more environmentally friendly than Ethylene glycol and not toxic to humans. Who is correct?
A: Technician A
B: Technician B
C: Both Technicians
D: Neither Technicians
C: Both Technicians
A recently overhauled inline 6 cylinder diesel engine has a scuffed cylinder and burnt piston crown, all other cylinders look fine. What is the most likely cause?
A: Blocked coolant passage
B: Improperly installed piston cooling nozzle
C: Low oil pressure
D: Overheated engine
B: Improperly installed piston cooling nozzle