Week #3 - Charging System

Question 1

What do we call the location on a cam profile that is exactly opposite the toe?

Answer 1

Heel

Question 2

On a cam profile described as mostly inner base circle, the profiles between IBC and OBC are known as what?

Answer 2

Ramps

Question 3

Which of the following dimensions would be consistent with a typical engine timing gear backlash setting?

a. 0.002” (0.05mm)
b. 0.024” (0.60 mm)
c. 0.008” (0.20 mm)
d. 0.014” (0.36 mm)

Answer 3

0.008” (0.20 mm)

Question 4

In which direction must a camshaft be rotated on a diesel engine with a crankshaft that is rotated clockwise?

a. Clockwise
b. Counterclockwise
c. Either clockwise or counterclockwise depending on the engine

Answer 4

Either clockwise or Counterclockwise depending on the engine

Question 5

Which tool would be required to measure the cam lift of a cylinder block-mounted camshaft in position?

Answer 5

A dial indicator

Question 6

A camshaft gear is usually precisely positioned on the camshaft using what?

Answer 6

Key and Keyway

Question 7

When grinding a valve face to remove pitting, the critical specification to monitor during machining would be what?

Answer 7

Margin

Question 8

Which of the following operating conditions would be more likely to cause a valve float condition?

a. Operating in the droop curve
b. Engine overspeed
c. Engine lug down
d. Operating in the torque rise profile

Answer 8

Engine overspeed

Question 9

When grinding a new set of cylinder valve seats, which of the following should be performed before the machining?

a. Install the valve guides
b. Adjust the valve yokes
c. Install the rockers
d. Install the valves

Answer 9

Install the valve guides

Question 10

What is the reason for using a pair of oppositely wound valve springs?

Answer 10

To minimize valve dynamic flutter

Question 11

Technician A states that the backlash in timing gearsets can be measured with a dial indicator. Technician B states that if the gear backlash is insufficient, the result can be gear whine. Who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 11

Both A and B

Question 12

Technician A states that helical cut gears are often used in engine timing geartrains because they operate more quietly. Technician B states that shaft thrust loads are much higher when helical cut gears are used. Who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 12

Both A and B

Question 13

Technician A states that when installing an interference-fit gear to a shaft, the gear should not be heated above 4008F. Technician B states that if an oxyacetylene rosebud is not available, an interference-fit gear should be pressed to the shaft using a hydraulic press. Who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 13

Technician A only

Question 14

Technician A states that it is good practice to lubricate the inside bores of camshaft bushings to facilitate camshaft installation. Technician B states that if the cam bushing oil holes are not properly aligned, an immediate camshaft failure could be the result. Who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 14

Both A and B

Question 15

Which of the following methods is used to transfer drive from the crankshaft to the camshaft on most commercial diesel engines?

a. Fluid coupling
b. Belt and pulley
c. Timing chain and sprocket
d. Gears

Answer 15

Gears

Question 16

Technician A states that variable valve timing (VVT) is used on some diesel engines to delay the closing of intake valves on the compression stroke. Technician B states that VVT is used to open the intake valves early during the power stroke. Who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 16

Technician A Only

Question 17

What type of cam geometry is required if the objective is to load the train that rides it for most of the cycle?

a. Mostly IBC profile
b. Mostly OBC profile
c. Symmetrical OBC and IBC profiles

Answer 17

Mostly OBC profile

Question 18

Technician A states that camshaft on a two-stroke cycle engine turns through one complete rotation per complete engine revolution. Technician B states that the camshaft on a four-stroke cycle diesel engine rotates through one revolution per two engine revolutions. Who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 18

Both A and B

Question 19

Technician A states that to check cam lift, the camshaft must be removed from the engine to obtain a valid reading. Technician B states that to check for a bent camshaft, the camshaft should be removed from the engine and runout tested in V-blocks. Who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 19

Technician B Only

Question 20

Technician A states that valves machined with 45-degree seats breathe with higher efficiencies than those machined with 30-degree seats. Technician B states that valves machined with 30-degree seats run cooler than those machined with 45-degree seats. Who is correct?
a. Technician A only b. Technician B only c. Both A and B d. Neither A nor B

Answer 20

Neither A nor B