Deck 7: Engine Powertrain Components

Question 1

Which of the following components is NOT an engine powertrain component?

A) piston
B) connecting rod
C) crankshaft
D) cylinder valves

Answer 1

cylinder valves

Question 2

Which of the following terms is used to describe a one-piece piston?

A) crosshead
B) articulating
C) ceramic
D) trunk

Answer 2

trunk

Question 3

Which of the following terms means the same as thing as a piston pin?

A) wrist pin
B) piston journal
C) piston boss
D) crosshead pin

Answer 3

wrist pin

Question 4

Which of the following piston types is likely to be cam ground?

A) aluminum trunk
B) two piece crosshead
C) two piece articulating
D) ceramic headland

Question 5

Which of the following features would be required in an aluminum alloy, trunk type piston when used in a commercial diesel engine application?

A) full floating wrist pin
B) ring groove insert (Ni-Resist)
C) chromed pin boss
D) tin plating

Question 6

How would a Mahle Monotherm piston be described?

A) aluminum trunk piston
B) forged steel trunk piston
C) composite steel trunk piston
D) steel and aluminum articulating piston

Question 7

Which of the following materials has the highest coefficient of heat transfer?

A) aluminum alloy
B) cast iron
C) cast iron alloy
D) plastic

Question 8

What percentage of cylinder combustion heat is typically absorbed by the piston assembly?

A) 10 percent
B) 20 percent
C) 50 percent
D) 80 percent

Question 9

What type of piston crown design is used on most current truck diesel engines?

A) dished
B) flat
C) Mexican hat
D) M type

Question 10

Which type of piston is closely associated with older Detroit Diesel engines?

A) articulating
B) crosshead
C) M type
D) flat crown

Question 11

Which of the following is NOT a common surface treatment for aluminum, trunk type pistons?

A) tin plating
B) anodizing
C) chrome plating
D) annealing

Question 12

In a two piece, articulating piston assembly in a commercial diesel engine, what material is typically used for the crown?

A) aluminum alloy
B) cast iron alloy
C) ceramic fiber
D) Ni-Resist

Question 13

In a two piece, articulating piston assembly, what material is usually used for the skirt?

A) aluminum alloy
B) cast iron
C) ceramic fiber
D) Ni-Resist

Question 14

Where does a wrist pin fit to a piston?

A) upper ring land
B) piston crown
C) pin boss
D) lower oil control groove

Question 15

What is known as headland volume in a piston assembly?

A) volume of ring belt sectional area
B) volume between the crown rim and top compression ring
C) volume between oil control ring and skirt
D) clearance volume above piston

Question 16

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

A) piston slap
B) thermal distortion
C) longevity
D) weight

Question 17

What is diametrically opposite to the piston major thrust face?

A) pin boss
B) cylinder head
C) anti-thrust face
D) crankshaft

Question 18

Which of the following terms is used to describe an engine with lower cylinder turbulence?

A) high horsepower
B) quiescent
C) passive
D) high swirl

Question 19

Technician A says that current forged steel trunk pistons use a shorter wrist pin than comparable articulating piston assemblies. Technician B says that a disadvantage of forged steel trunk pistons such as Monotherm is much greater weight than comparable bore, aluminum trunk pistons. Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 20

Which of the following piston cooling methods is used in most high horsepower, turbocharged diesel engines?

A) spray jet
B) water cooled
C) coolant cooled
D) ambient air cooled

Question 21

Which of the following is an indication of too little piston to liner clearance?

A) upper engine knock
B) lower engine knock
C) scoring and scuffing
D) slow cold cranking rpm

Question 22

Where is a piston ring installed in the piston assembly?

A) pin boss
B) ring groove
C) ring land
D) crown

Question 23

What is primarily responsible for a compression ring's ability to seal gas pressure?

A) radial pressure
B) cylinder pressure
C) ring tension
D) piston speed

Question 24

What is the ring land and groove area of a piston known as?

A) headland
B) crown recess
C) ring belt
D) skirt

Question 25

Which type of ring joint is most effective in sealing cylinder blow-by gas?

A) straight joint
B) angle joint
C) barrel joint
D) step joint

Question 26

Which category of top compression ring is used on most current highway diesel engines?

A) rectangular
B) rectangular, taper face
C) keystone
D) oval

Question 27

What is usually installed into the Ni-Resist insert of a piston assembly?

A) upper compression ring
B) wrist pin
C) piston skirt
D) oil control ring

Question 28

Which of the following ring arrangements would be most common on current medium and large bore truck diesel engines?

A) one compression, one oil control
B) two compression, one oil control
C) three compression, two oil control
D) four compression, two oil control

Question 29

A diesel engine piston has two compression and one oil control ring. What would probably be the recommended ring stagger?

A) 90 degrees
B) 120 degrees
C) 150 degrees
D) 180 degrees

Question 30

Which of the following best describes the sectional shape of a keystone ring?

A) oval
B) round
C) rectangular
D) wedge

Question 31

Viewed from the front, a Cummins ISX rotates clockwise. On which side are the piston major thrust faces be located?

A) right side
B) left side
C) front
D) rear

Question 32

In a piston assembly using snap rings to retain the wrist pin, what is the usual recommended location of the split joint after installation?

A) facing forward
B) facing rear
C) facing up
D) facing down

Question 33

What is used to link a piston with a connecting rod?

A) wrist pin
B) piston journal
C) rod eye
D) rod big end

Question 34

Technician A says that the upside of a piston ring is often identified by a dot. Technician B measures a ring end gap of 0.018 inch in 5-inch diameter cylinder bore and says that it almost certainly exceeds the OEM specification. Who is correct?

A) Technican A only
B) Technican B only
C) Both A and B
D) Neither A nor B

Question 35

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

A) engine overspeed
B) excess ether usage
C) high cylinder pressures
D) drive train shock load

Question 36

Which of the following identifies the correct companion cylinder pairings in an in-line 6-cylinder engine?

A) 1 - 2, 3 - 4, 5 - 6
B) 1 - 5, 3 - 6, 2 - 4
C) 1 - 6, 2 - 5, 3 - 4
D) 6 - 5, 4 - 3, 2 - 1

Question 37

What is the correct firing sequence for an in-line, 6-cylinder diesel engine?

A) 1 - 5 - 3 - 6 - 2 - 4
B) 1 - 2 - 3 - 4 - 5 - 6
C) 6 - 5 - 4 - 3 - 2 - 1
D) 1 - 6 - 5 - 2 - 3 - 4

Question 38

What is the most common method of surface hardening the journals on a heavy-duty crankshaft?

A) flame hardening
B) nitriding
C) anodizing
D) induction hardening

Question 39

Which of the following do current forged steel trunk type pistons primarily depend on to lubricate the wrist pins?

A) lube oil delivered through conn rod rifle
B) splash lube from oil sump
C) spray cooling jets
D) lube transfer from cylinder wall

Question 40

Which of the following would be least likely to cause a torsional crankshaft failure?

A) defective vibration damper
B) unbalanced cylinder loading
C) misaligned main bearing bore
D) defective engine mounts

Question 41

A crankshaft has been damaged by a spun bearing. What would be the recommended OEM repair?

A) replace crankshaft
B) metallize to original size
C) chrome surface
D) submerged arc welding to original size

Question 42

What is Plastigage^TM used for measuring?

A) crankshaft endplay
B) big end side play
C) friction bearing clearance
D) flywheel runout

Question 43

A viscous type vibration damper shows trace fluid leakage. Which of the following is recommended?

A) seal with silicone
B) check with a balance sensor
C) repair weld the crack
D) replacement

Question 44

Which of the following measurements would be a likely specification for crankshaft endplay in a heavy-duty highway diesel engine?

A) 0.002 - 0.003 inches
B) 0.004 - 0.006 inches
C) 0.008 - 0.012 inches
D) 0.012 - 0.018 inches

Question 45

If crankshaft endplay is higher than specified, which of the following should be used to correct the condition?

A) oversized thrust bearings
B) undersized thrust bearings
C) oversized main bearings
D) undersized main bearings

Question 46

When main bearing shells are installed to an engine cylinder block, what should be used to lubricate the backing plate?

A) nothing
B) engine lube
C) libriplate
D) silicone

Question 47

When main bearing shells are installed to an engine cylinder block, what should be used to lubricate the bearing face?

A) nothing
B) engine lube
C) lubriplate
D) silicone

Question 48

What is used to retain friction bearings?

A) tangs
B) spread
C) thrust
D) crush

Question 49

How is a ring gear fitted to a flywheel?

A) staking
B) heat shrink
C) welding
D) freezing

Question 50

When does an oil control ring apply lubricant to the cylinder wall?

A) on upstroke
B) on downstroke
C) on upstroke and downstroke
D) at TDC and BDC

Question 51

Which of the following is a major advantage of using quiescent combustion dynamics in truck diesel engine?

A) increases engine power
B) reduces afterburn and soot emissions
C) requires increased injection pressures
D) simplifies piston crown design

Question 52

Where did cracked rod technology originate?

A) race car engines
B) the arctic
C) Cleveland
D) Sweden

Question 53

What is the primary advantage of a cracked connecting rod?

A) lighter weight
B) less machining required
C) no friction bearings required
D) perfect alignment of rod cap to rod

Question 54

Which of the following piston types is the most common in large bore highway diesel engines built after 2007?

A) aluminum trunk
B) forged steel trunk
C) crosshead articulating
D) full articulating

Question 55

What is the brand name ofthe largest manufacturer of forged steel trunk pistons used in commercial diesel engines?

A) Caterpillar
B) Cummins
C) Monotherm
D) Ferrotherm

Question 56

Technician A says that Monotherm pistons are manufactured with a much tighter fit to the liner bore than aluminum trunk pistons. Technician B says that Monotherm pistons do not require an oil spray jet aimed at the underside of the piston. Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 57

Technician A says that Monotherm pistons feature a bushingless wrist pin bore. Technician B says that forged steel pistons are usually equal in weight to equivalent bore aluminum trunk pistons because much less material is used in their construction. Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 58

Technician A says that forged steel trunk pistons expand and contract much less than comparable aluminum trunk pistons. Technician B says that forged steel trunk pistons are specified for diesel engines with lower peak cylinder pressures than those that use articulating pistons. Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 59

Technician A says that engines using quiescent combustion dynamics tend to use more aggressive Mexican hat cones. Technician B says that injected fuel droplets are directed into the crater (toroidal recess) in Mexican hat piston crowns. Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 60

What is another way of describing the toroidal recess in a Mexican hat type piston?

A) cone
B) crater
C) piston leading edge
D) skirt wall assembly

Question 61

When fuel is injected into a diesel engine cylinder, to which part of the piston are the atomized droplets targeted?

A) Mexican hat crown
B) piston crown leading edge
C) upper compression ring
D) toroidal recess

Question 62

Technician A says that a disadvantage of forged steel trunk pistons is reduced headland volume when compared with articulating pistons. Technician B says that when a diesel engine uses lighter pistons, higher rpms are possible. Who is correct?

A) Technician A only
B) Technician Bonly
C) Both A and B
D) Neither A nor B

Question 63

Which of the following correctly describes a Ferrotherm piston?

A) aluminum trunk
B) forged steel trunk
C) articulating
D) crosshead

Question 64

Which of the following terms correctly describes a Mahle Monocomp piston?

A) composite steel trunk
B) forged steel trunk
C) articulating
D) crosshead