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OTC - Diesel Engines I DET-101 > Week #3 Engine Assembly > Flashcards

Week #3 Engine Assembly Flashcards

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1
Q

When selective fitting a set of dry liners to a cylinder block, which of the following statements should be true?
a. The liners are installed with an interference fit
b. The liner with the largest od is fitted to the bore with the largest id
The liners are installed with a fractionally loose fit
d. the liner with the smallest od is fitted to the bore with the largest id

A

b. The liner with the largest od is fitted to the bore with the largest id

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2
Q

When cylinder block counterbores are machined, which of the following would be required?

a. Cylinder head resurfacing
b. Oversize fire ring
c. Undersize liner flange
d. Shims

A

d. Shims

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3
Q

`True or False: All the machined surfaces of a cylinder block should be checked to specification with a straightedge and thickness gauges.

A

True

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4
Q

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

A

Key and Keyway

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5
Q

True or False:All cylinder heads on current engines should be hot torqued after a rebuild procedure.

A

False

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6
Q

Which of the following is a disadvantage of an articulating piston assembly when compared to an aluminum alloy trunk piston?

a. Service life
b. Increased tensile loading on the connecting rods
c. Piston slap control
d. Highest possible location of an upper ring groove

A

b. Increased tensile loading on the connecting rods

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7
Q

If the cam bushing oil holes are not properly aligned, an immediate camshaft failure could be the result.

A

True

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8
Q

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

a. margin
b. shank diameter
c. poppet diameter
d. stem

A

a. margin

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9
Q

True or False: Variable valve timing (VVT) is used to open the intake valves early during the power stroke.

A

False

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10
Q

True or False: Main bearing shells are usually interchangeable and may be installed in either the upper or lower position.

A

False

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11
Q

True or False: Cylinder blocks should be boiled in a soak tank at every major overhaul.

A

True

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12
Q

True or False: When installing an interference-fit gear to a shaft, the gear should not be heated above 4008F.

A

True

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13
Q

True or False: Shaft thrust loads are much ;higher when helical cut gears are used.

A

True

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14
Q

The main reason for bench pressure testing a diesel engine cylinder head is to ________.

A

Check for coolant leaks

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15
Q

True or False: Helical cut gears are often used in engine timing geartrains because they operate more quietly.

A

True

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16
Q

Which of the following is the recommended method of pulling dry liners from a cylinder blcok?

a. Fracture the liner in position
b. The arc welding method
c. A puller and shoe assembly
d. Heat and shock cool method

A

c. A puller and shoe assembly

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17
Q

Rod and main journal bearing clearances are properly measured with what?

A

Plastigage

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18
Q

Which of the following cylinder block designs would be the most common in medium- and heavy-duty truck diesel engines?

a. Inline eight cylinder
b. Inline six cylinder
c. Six cylinder, 60-degree V-configuration
d. Eight-cylinder, 90-degree V-confuration

A

b. Inline six cylinder

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19
Q

True or False: The backlash in timing gearsets can be measured with a dial indicator.

A

True

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20
Q

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

A

Minimize valve dynamic flutter

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21
Q

True or False: It is good practice to lubricate the inside bores of camshaft bushings to facilitate camshaft installation.

A

True

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22
Q

Which of the following is true of a CFA piston?

a. It is type of Ni-Resist insert
b. The ring belt operates at higher temperatures
c. The ring belt reinforcement insert extends up into the leading edge of the piston
d. It is used only on articulating pistons

A

c. The ring belt reinforcement insert extends up into the leading edge of the piston

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23
Q

The inertia ring drive medium on a viscous-type vibration damper is rubber compound.

A

False

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24
Q

True or False:It is good practice to magnetic flux test a cylinder block for cracks at each major overhaul.

A

True

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25
Q

What should be used to install piston rings onto a piston?

A

A ring expander

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26
Q

Where would a Ni-Resist insert be located?

A

Upper ring belt, aluminum trunk piston

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27
Q

True or False: The camshaft on a four-stroke cycle diesel engine rotates through on revolution per two engine revolutions.

A

True

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28
Q

Excessive clearance at the crankshaft main bearing could result in which of the following conditions?

a. Low oil pressure
b. High oil pressure
c. Aerated oil
d. Fluctuating oil pressures

A

a. Low oil pressure

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29
Q

A crankshaft has a fracture failure that appears to have initiated at a throw journal oil hole. which of the following would be the most likely cause?

a. A spun rod bearing
b. A failed vibration damper
c. A broken main cap
d. Excessive cylinder pressure

A

b. A failed vibration damper

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30
Q

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

A

Ramps

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31
Q

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. Install the valves
c. Install the rockers
d. Adjust the valve yokes

A

a. Install the valve guides

32
Q

The piston crown design most commonly used by OEMs in today’s highway diesel engines is what?

A

Mexican hat

33
Q

True or False: The camshaft on a two-stroke cycle engine turns through one complete rotation per complete engine revolution.

A

True

34
Q

True or False: Variable valve timing (VVT) is used on some diesel engines to delay the closing of intake valves on the compression stroke.

A

True

35
Q

True or False: A cam ground piston is circular when cold and expands to an elliptical shape at operating temperature.

A

False

36
Q

Which of the following tools should be used to check a cylinder block deck for warpage?

a. Dial indicator
b. Straightedge and thickness gauges
c. Master bar
d. Laser

A

b. Straightedge and thickness gauges

37
Q

When observing a dissembled engine, the outer crown edges of all six pistons show signs of meting and erosion. This could be cause by:

a. a dribbling injector
b. fuel with high sulfur content
c. retarded timing
d. advanced timing

A

d. advanced timing

38
Q

What type of piston is favored by diesel engine OEMs in post-2007 products?

A

Forged steel trunk

39
Q

The upper face of a piston assembly is called what?

A

Crown

40
Q

When crankshaft thrust surfaces are reground, which of the following would be true?

a. Oversize thrust bearings are required
b. Undersize thrust bearings are required
c. The thrust washers must be machined to a smaller dimension
d. The thrust washers must be shimmed

A

a. Oversize thrust bearings are required

41
Q

True or False: To check cam list, the camshaft must be removed from the engine to obtain a valid reading.

A

False

42
Q

Which of the following engine conditions would be the likely cause of a tensile failure of a connecting rod?

a. High cylinder pressures
b. Prolonged engine idling
c. Prolonged lug down
d. Engine overspeed

A

d. Engine overspeed

43
Q

True or False: Valves machined with 45-degree seats breathe with higher inefficiencies than those machined with 30-degree seats.

A

False

44
Q

What would be the consequence of a misdirected piston oil cooling jet?

A

Torched piston

45
Q

Which of the following journal surface hardening methods would provide the highest machinability margin?

a. Nitriding
b. Shot peening
c. Induction hardening
d. Flame hardening

A

c. Induction hardening

46
Q

When boiling out a cylinder block, why is it critical that all the scale in the water jacket be removed?

a. Scale can accelerate coolant silicate drop-out
b. Scale may contaminate the engine lubricant
c. Scale causes cavitation of wet liners
d. Scale is an effective insulator

A

d. Scale is an effective insulator

47
Q

Which of the following would be the more likely outcome of running an engine with a failed vibration damper?

a. Crankshaft failure
b. Camshaft failure
c. Increased cylinder blowby
d. Increased fuel consumption

A

a. Crankshaft failure

48
Q

True or False: To check for a bent camshaft, the camshaft should be removed from the engine and runout tested in V-blocks

A

True

49
Q

The reason the cam ground piston is elliptical when cold is to accommodate the thermal expansion of the greater mass of material at the piston boss as it is raised to operating temperature.

A

True

50
Q

True or False: Keystone connecting rods have a wedge-shaped big end.

A

False

51
Q

The location on a cam profile that is exactly opposite the toe is referred to as what?

A

Heel

52
Q

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

A

c. Either clockwise or counterclockwise depending on the engine

53
Q

Which of the following types of pistons use bushingless pin bosses?

a. Monotherm
b. Ferrotherm
c. Aluminum alloy
d. Crosshead

A

a. Monotherm

54
Q

Which of the following tools should be used to check a cylinder head for warpage?

a. Laser
b. Dial indicator
c. Master bar
d. Straightedge and thickness gauges

A

d. Straightedge and thickness gauges

55
Q

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

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

A

b. Mostly OBC profile

56
Q

True or False: Valves machined with 30-degree seats run cooler than those machined with 45-degree seats.

A

False

57
Q

Into what area of a Mexican hat combustion chamber are the injected droplets of fuel directed?

A

Crater

58
Q

Once a cylinder head gasket fire ring has been torqued to its yield point, it should:

a. deform and no longer seal effectively
b. not be reused after removal
d. immediately be heated to operating temperature

A

b. not be reused after removal

59
Q

If an oxyacetylene rosebud is not available, an interference-fit gear should be pressed to the shaft using a hydraulic press.

A

False

60
Q

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

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

A

d. Engine overspeed

61
Q

True or False:Cylinder head bolts should e soaked in engine lubricating oil before installation.

A

False

62
Q

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

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

A

a. 0.008” (0.20 mm)

63
Q

Most current heavy-duty, diesel engine cylinder blocks are manufactured from:

a. composite fibers
b. cast-iron alloys
c. compacted graphite iron (CGI)
d. cast aluminum alloy

A

c. compacted graphite iron (CGI)

64
Q

Which of the following tools is recommended for checking cylinder block line boare?

a. Master line bore bar
b. Straightedge and thickness gauges
c. Dial bore gauge
d. Dial indicator

A

a. Master line bore bar

65
Q

True or False: Before performing a magnetic flux test, the cylinder block should be boiled in a soak tank.

A

True

66
Q

Which of the following operating modes would be more likely to result in a compressional failure of a connecting rod?

a. Prolonged high idle running
b. Prolonged low idle running
c. Hydraulic lock caused by head gasket failure
d. Overspeeding engine

A

c. Hydraulic lock caused by head gasket failure

67
Q

Which term is used to describe the cylinder volume between the piston upper compression ring and its leading edge?

A

Headland volume

68
Q

True or False: The type of vibration damper most commonly used on truck diesel engines is the viscous type.

A

True

69
Q

When cavitation damage is evident on a set of wet liners, which of the following is more likely to be responsible?

a. Coolant breakdown
b. Lubrication breakdown
c. High cylinder pressures
d. Cold engine operation

A

a. Coolant breakdown

70
Q

True or False: Keystone rings are most common in current diesel engines.

A

True

71
Q

Under which of the following conditions would a piston ring seal more effectively?

a. High engine temperatures
b. High cylinder pressures
c. Low engine temperatures
d. Low cylinder pressures

A

b. High cylinder pressures

72
Q

The main bearing shell with an oil hole must always be installed in the main bearing cap.

A

False

73
Q

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

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

A

a. Gears

74
Q

True or False: If the gear backlash is insufficient, the result can be gear whine.

A

True

75
Q

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

A

A dial indicator

OTC - Diesel Engines I DET-101 (6 decks)

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