Question 1

What is another way of saying engine longevity?
A) engine length
B) expected engine life
C) engine serviceability
D) engine warranty period

Accepted Answer

Expected engine life is synonymous with engine longevity, as both terms refer to the duration an engine is expected to operate effectively before requiring major repairs or replacement.

Question 2

What is the preferred run-in method for a highway diesel engine after an overhaul?
A) do not exceed 50 mph for the first 1000 miles
B) do not run at full load for the first 500 miles
C) full load operation on a dynamometer
D) highway road test

Accepted Answer

Running a diesel engine at full load on a dynamometer after an overhaul helps to ensure that all components are properly seated and functioning, allowing for controlled conditions to monitor performance and make necessary adjustments.

Question 3

When a truck diesel engine is run in a linehaul application, how is the truck being run?
A) highway, terminal to terminal
B) vocational
C) LTL, pick-up and delivery
D) construction hauling

Accepted Answer

Linehaul applications typically involve long-distance hauling from one terminal to another, primarily on highways.

Question 4

What is the preferred method of priming an engine lubrication system with engine oil?
A) Hand prime the turbocharger
B) Hand prime the oil filters
C) Hand prime the oil cooler
D) Use a prelubricator

Accepted Answer

Using a prelubricator is the preferred method for priming an engine lubrication system because it ensures that oil reaches all critical components of the engine before it starts, reducing the risk of wear or damage due to insufficient lubrication.

Question 5

When instructed to hand prime a full flow oil filter, which of the following procedures is correct?
A) immerse filter in fresh oil
B) fill the filter with clean engine oil
C) silicone the filter sealing gasket
D) purge air at the filter pad

Accepted Answer

Filling the filter with clean engine oil is the correct procedure for hand priming a full flow oil filter. This ensures that the engine is not starved of oil upon startup, as the filter is already filled with oil and can immediately supply the engine.

Question 6

In order to purge air from a diesel engine cooling system after reconditioning, which of the following is recommended?
A) separate the upper radiator hose
B) remove the radiator drain plug
C) remove the thermostat housing
D) vent circuit by cracking a water manifold plug

Accepted Answer

Venting the circuit by cracking a water manifold plug is a common method to purge air from a diesel engine cooling system after reconditioning. This allows trapped air to escape as the system is filled with coolant, ensuring proper circulation and cooling efficiency.

Question 7

Which of the following steps is recommended following a diesel engine rebuild to check for leaks before allowing it to start?
A) no-fuel crank for 15 seconds
B) no-fuel crank for 2 minutes
C) charge intake with ether
D) pressure test cooling system

Accepted Answer

Performing a no-fuel crank for 15 seconds allows you to check for any leaks or issues without starting the engine, ensuring that everything is functioning properly before full operation.

Question 8

Which of the following methods of priming a diesel fuel system is NOT recommended?
A) crack fitting at fuel transfer pump outlet
B) loosen fitting at secondary filter outlet
C) purge fuel water separator
D) pressurize fuel tank with shop air

Accepted Answer

Pressurizing the fuel tank with shop air is not recommended as it can cause damage to the fuel system and create safety hazards.

Question 9

Which of the following values represents a typical maximum oil temperature specification in a diesel engine?
A) 195 degrees Fahrenheit
B) 225 degrees Fahrenheit
C) 240 degrees Fahrenheit
D) 275 degrees Fahrenheit

Accepted Answer

240 degrees Fahrenheit is a typical maximum oil temperature specification for diesel engines to ensure proper lubrication and prevent overheating.

Question 10

Which of the following values represents a typical maximum diesel engine coolant temperature specification?
A) 180 degrees Fahrenheit
B) 195 degrees Fahrenheit
C) 200 degrees Fahrenheit
D) 250 degrees Fahrenheit

Accepted Answer

A typical maximum diesel engine coolant temperature specification is around 200 degrees Fahrenheit, which is a common threshold for many diesel engines to ensure efficient operation without overheating.

Question 11

Which type of dynamometer functions similarly to an electric motor turned in reverse?
A) hydromechanical
B) mechanical
C) electronic
D) Electric motor

Accepted Answer

Electric motor dynamometers function similarly to an electric motor turned in reverse, where they convert mechanical energy into electrical energy, mimicking the operation of an electric motor but in the opposite direction.

Question 12

What is the hydraulic medium used in a typical truck chassis dynamometer?
A) water
B) hydraulic oil
C) transmission oil
D) engine oil

Accepted Answer

The answer of What is the hydraulic medium used in...

Question 13

When installing a tandem drive axle truck on a chassis dynamometer, which wheels must be wedged and chained?
A) front axle wheels
B) forward drive axle only
C) rear drive axle only
D) both drive axles

Accepted Answer

When installing a tandem drive axle truck on a chassis dynamometer, it is essential to ensure safety and stability. The front axle wheels must be wedged and chained to prevent the vehicle from moving forward or backward during the testing process. This is because the dynamometer applies force to the drive axles, potentially causing the vehicle to shift if not properly secured. The drive axles themselves are engaged with the dynamometer and thus are not wedged and chained.

Question 14

When running a truck on a chassis dynamometer, what gear ratio should be selected for most of the test sequence?
A) the lowest gear
B) the highest gear
C) 1:1 ratio
D) highest gear in low range

Accepted Answer

The 1:1 gear ratio is typically selected for most of the test sequence when running a truck on a chassis dynamometer because it provides a direct drive scenario, minimizing the influence of the transmission on the test results and allowing for more accurate measurement of the engine's performance.

Question 15

When a double roller type chassis dynamometer is used to test a truck, what is the maximum speed difference permissible between the rear axles?
A) 0 mph
B) 5 mph
C) 10 mph
D) 15 mph

Accepted Answer

The maximum speed difference permissible between the rear axles when using a double roller type chassis dynamometer to test a truck is 5 mph. This is to ensure accurate testing and prevent damage to the vehicle's drivetrain.

Question 16

When using a dynamometer to break in a set of piston rings on a rebuilt diesel engine, what is the minimum period the engine should be run at maximum power at rpms within its torque rise profile?
A) five minutes
B) ten minutes
C) twenty minutes
D) forty minutes

Accepted Answer

Running the engine at maximum power within its torque rise profile for twenty minutes is essential for properly seating the piston rings during the break-in process. This duration allows the rings to properly mate with the cylinder walls, ensuring a good seal and optimal engine performance.

Question 17

Following a full load dynamometer test, what is the minimum period the engine should be run at idle speed before shut down?
A) five minutes
B) ten minutes
C) twenty minutes
D) forty minutes

Accepted Answer

Running the engine at idle speed for five minutes after a full load dynamometer test allows it to cool down gradually, preventing thermal shock and ensuring the turbocharger has time to slow down safely.

Question 18

What percentage of brake horsepower is produced at a set of tandem axle drive wheels compared with brake horsepower produced at the flywheel?
A) 50 - 55 percent
B) 80 - 85 percent
C) 100 percent
D) 120 - 125 percent

Accepted Answer

The brake horsepower at the drive wheels is typically lower than at the flywheel due to drivetrain losses, which are usually around 15-20%, resulting in 80-85% of the flywheel horsepower being delivered to the wheels.

Question 19

What is the main safety reason that no person should be outside the vehicle in a chassis dynamometer test room during testing?
A) combusted diesel fumes
B) unpleasant odor from tires
C) stones may dislodge from tires
D) high noise level

Accepted Answer

Stones or other debris can dislodge from the tires during a chassis dynamometer test, posing a significant safety hazard to anyone in the vicinity.

Question 20

Which of the following is the most important requirement before taking a truck out on a road test?
A) circle test
B) check oil level
C) driver is properly licensed
D) check coolant level

Accepted Answer

The most important requirement before taking a truck out on a road test is ensuring the driver is properly licensed. This is crucial for legal and safety reasons, as an unlicensed driver would not be legally permitted to operate the vehicle on public roads.

Quiz 16: Diesel Engine Run- in and Performance Testing

What is another way of saying engine longevity?

What is the preferred run-in method for a highway diesel engine after an overhaul?

When a truck diesel engine is run in a linehaul application, how is the truck being run?

What is the preferred method of priming an engine lubrication system with engine oil?

When instructed to hand prime a full flow oil filter, which of the following procedures is correct?

In order to purge air from a diesel engine cooling system after reconditioning, which of the following is recommended?

Which of the following steps is recommended following a diesel engine rebuild to check for leaks before allowing it to start?

Which of the following methods of priming a diesel fuel system is NOT recommended?

Which of the following values represents a typical maximum oil temperature specification in a diesel engine?

Which of the following values represents a typical maximum diesel engine coolant temperature specification?

Which type of dynamometer functions similarly to an electric motor turned in reverse?

What is the hydraulic medium used in a typical truck chassis dynamometer?

When installing a tandem drive axle truck on a chassis dynamometer, which wheels must be wedged and chained?

When running a truck on a chassis dynamometer, what gear ratio should be selected for most of the test sequence?

When a double roller type chassis dynamometer is used to test a truck, what is the maximum speed difference permissible between the rear axles?

When using a dynamometer to break in a set of piston rings on a rebuilt diesel engine, what is the minimum period the engine should be run at maximum power at rpms within its torque rise profile?

Following a full load dynamometer test, what is the minimum period the engine should be run at idle speed before shut down?

What percentage of brake horsepower is produced at a set of tandem axle drive wheels compared with brake horsepower produced at the flywheel?

What is the main safety reason that no person should be outside the vehicle in a chassis dynamometer test room during testing?

Which of the following is the most important requirement before taking a truck out on a road test?