Deck 35: Crankshafts, Balance Shafts, and Bearings

Question 1

A forged crankshaft has a ________.

A)Wide parting line
B)Thin parting line
C)Parting line in one place
D)Both B and C

Answer 1

Wide parting line

Question 2

A typical V-8 engine crankshaft has ________ main bearings.

A)Five
B)Three
C)Four
D)Seven

Answer 2

Five

Question 3

A four-cylinder engine fires one cylinder at every ________ degrees of crankshaft rotation.

A)270
B)120
C)90
D)180

Answer 3

180

Question 4

A splayed crankshaft is a crankshaft that ________.

A)Has offset main bearing journals
B)Is externally balanced
C)Has offset rod journals
D)Is internally balanced

Question 5

The thrust bearing surface is located on one of the main bearings to control thrust loads caused by ________.

A)Lugging the engine
B)Torque converter or clutch release forces
C)Rapid deceleration forces
D)Both A and C

Question 6

If any crankshaft is ground, it must also be ________.

A)Polished
B)Externally balanced
C)Chrome plated
D)Shot peened

Question 7

If bearing-to-journal clearance is doubled, how much oil will flow?

A)One-half as much
B)Four times the amount
C)Double the amount
D)The same amount if the pressure is kept constant

Question 8

Typical journal-to-bearing clearance is ________.

A)0.150 to 0.250 inch
B)0.020 to 0.035 inch
C)0.0005 to 0.0025 inch
D)0.00015 to 0.00018 inch

Question 9

A bearing shell has a sightly larger arc than the bearing housing. This difference is called ________.

A)Bearing saddle
B)Bearing spread
C)Bearing tang
D)Bearing crush

Question 10

Bearing ________ occurs when a bearing shell is slightly above the parting surface of the bearing cap.

A)Overlap
B)Cap lock
C)Crush
D)Interference fit

Question 11

Crankshafts should be stored by which of these methods?

A)Any position
B)Leaning at a slight angle
C)Standing or hanging
D)Standing or lying on its side

Question 12

Technician A says that oil for the rod bearings comes from splash off the crankshaft. Technician B says that lubrication to the main bearings is fed through the main oil gallery in the block. Who is right?

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

Question 13

Technician A says that a vibration damper, also known as a harmonic balancer, is used to dampen harmful twisting vibrations of the crankshaft. Technician B says that most engines are balanced after manufacturing. Who is right?

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

Question 14

Crankshaft journals are checked for which of these?

A)Out of Round
B)Taper
C)Both A and B
D)Neither A nor B

Question 15

The crankshaft journals have been turned. What size bearings should be installed?

A)It makes no difference which size is installed
B)Undersize
C)Standard
D)Oversize

Question 16

Technician A says that most crankshafts can be reground to be 0.010, 0.020, or 0.030 inch undersize. Technician B says that most engine bearings are constructed with an aluminum shell for strength and are covered with a tin-lead alloy. Who is right?

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

Question 17

Technician A says that many bearings also have a thin overlay of babbitt. Technician B says that bearings should have spread and crush to keep them from spinning when the crankshaft rotates. Who is right?

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

Question 18

Technician A says balance shafts are used to counteract vibration created in the engine. Technician B says proper balancing of the engine is important for smooth operation. Who is right?

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

Question 19

Technician A says primary vibration is created by the slight differences in the inertia of the pistons between top dead center and bottom dead center. Technician B says secondary vibration is a strong low-frequency vibration caused by the movement of the piston traveling up and down in the cylinder. Who is right?

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

Question 20

Which of these causes primary vibration?

A)Pistons
B)Flywheel
C)Harmonic balancer
D)Flexplate

Question 21

Why does a 4-cylinder engine have very little, if any, primary vibration?

A)Uses a splayed crankshaft
B)Bore is small, reducing the primary vibration
C)Two pistons traveling upward at the same time two pistons are traveling downward
D)Two cylinders fire at the same time, reducing the primary vibration

Question 22

Which of these is a primary cause of secondary vibration?

A)Harmonic balancer
B)Connecting rod big ends
C)Flexplate
D)Pistons

Question 23

A balance shaft used in a 90-degree V-6 engine is used to correct which of these types of force?

A)Secondary vibration
B)Rolling couple
C)Rocking couple
D)Primary vibration

Question 24

In ________ engines, the cam bearings are installed in the block.

A)Pushrod
B)Two-stroke
C)Rotary
D)Overhead cam

Question 25

Which one of these is a thrust bearing?

A)a
B)b
C)c
D)d