Deck 12: Pistons, Rings, and Connecting Rods

Question 1

Technician A says the oil rings account for 60% of total drag on the cylinder wall. Technician B says the compression rings account for 40% of total drag on the cylinder wall. Who is right?

A)Technician A
B)Technician B
C)Both technicians
D)Neither technician

Answer 1

C

Question 2

Technician A says that a good piston can be ruined by cleaning the grooves on a wire wheel. Technician B says an old, broken piston ring works well to clean the ring grooves. Who is right?

A)Technician A
B)Technician B
C)Both technicians
D)Neither technician

Answer 2

C

Question 3

Technician A says a wrist pin is also known as a piston pin. Technician B says a piston pin is chrome-plated, high grade carbon steel. Who is correct?

A)Technician A
B)Technician B
C)Both technicians
D)Neither technician

Answer 3

C

Question 4

Piston diagnosis is being discussed. Technician A says scuffing on one skirt only can be caused by excessive low rpm idling. Technician B says scuffing of the piston skirt can be caused by abnormal combustion or cooling system problems. Who is right?

A)Technician A
B)Technician B
C)Both technicians
D)Neither technicians

Question 5

Piston rings are made from all these materials, EXCEPT _____.

A)ductile iron
B)aluminum wire
C)steel wire
D)cast iron

Question 6

All of the below are coatings used to reduce friction on pistons, EXCEPT _____.

A)Teflon
B)silicone
C)graphite
D)moly

Question 7

The big end of a rod can be up to 0.004" out of round before it needs resizing.

Question 8

Automobile piston pins are either pressed fit or full floating.

Question 9

Technician A says reverse twist rings do better controlling blowby. Technician B says standard torsional twist rings do better controlling oil. Who is correct?

A)Technician A
B)Technician B
C)Both technicians
D)Neither technician

Question 10

Name four common piston head shapes.

Question 11

Name the four forces that combine to push piston rings against the cylinder wall.

Question 12

Ring gaps on an opposed engine design should be faced down.

Question 13

The side of the piston that pushes on the cylinder wall during the power stroke is called the ____ surface.

Question 14

Technician A says powder forged rods are not cut; they are fractured (broken). Technician B says some rods have a spit hole to lubricate the cylinder walls at lower rpms. Who is right?

A)Technician A
B)Technician B
C)Both technicians
D)Neither technician

Question 15

Technician A says that the top compression ring groove wears more than the other ring grooves. Technician B says that full floating, piston pin lock rings should be installed with their openings facing up. Who is correct?

A)Technician A
B)Technician B
C)Both technicians
D)Neither technician

Question 16

A full skirt piston used on longer stroke engines is known as a(n) ____ piston.

Question 17

Most of today's automotive pistons are slipper skirt pistons.

Question 18

Technician A says a piston usually has a direction identifying notch that faces the rear of the engine. Technician B says a piston exhibits more wear on its major thrust side. Who is right?

A)Technician A
B)Technician B
C)Both technicians
D)Neither technician

Question 19

Hypereutectic is the description of a popular cast aluminum alloy referring to the percentage of silicon in the aluminum in a piston.

Question 20

Technician A says forged pistons are available for heavy-duty or high-performance use. Technician B says that a cast piston is more efficient at dissipating heat.

A)Technician A
B)Technician B
C)Both technicians
D)Neither technician

Question 21

Technician A says that installing a compression ring upside down can cause oil consumption. Technician B says that the top compression ring groove usually suffers more wear than the other ring grooves. Who is right?

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

Question 22

What is the name of the piston pin retaining method where the piston pin has a bushing in the connecting rod and lock rings at the ends of the piston bore?

Question 23

Where is the largest diameter of the piston found?

Question 24

Piston balance is more important with in-line engines than with V-type engines.
A. True
B. False

Question 25

What tool is used to check piston ring end gap clearance?

Question 26

Which type of cylinder arrangement sometimes uses offset connecting rods?

Question 27

Why is the piston pin bore offset from the piston centerline?

Question 28

What is the name of a piston that has a full skirt all the way around its bottom?

Question 29

Which of the following statements is/are true when installing full-floating piston pin lock rings?

A)They should be installed with their openings facing up.
B)They should be installed with the rounded side facing outward.
C)Both A and B
D)Neither A nor B

Question 30

Technician A says that cast pistons run cooler than forged pistons. Technician B says that cast pistons are stronger than forged pistons. Who is right?

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

Question 31

What is the name of the style of piston skirt that is cut away on the sides to allow clearance for the crankshaft counterweights?

Question 32

Why is there a hole or slot in the oil ring groove?

Question 33

How much can the cylinder bore be out of round when using moly or chrome piston rings?

Question 34

Which ring groove wears the most?

Question 35

How is a top ring groove checked for excessive wear?

Question 36

Which is larger: the diameter of the head or crown of the piston or the diameter of the skirt?

Question 37

Does a 0.030" oversized piston weigh the same as the original standard piston?

Question 38

Technician A says that some piston rings have chamfers or reliefs cut into them to cause them to twist. Technician B says that chrome rings should not be used in out-of-round cylinders. Who is right?

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

Question 39

What is the most common method of retaining the piston pin?

Question 40

Technician A says that the full skirt piston used on long stroke engines is called a "slipper" skirt. Technician B says that a piston skirt that is cut away on its sides to clear the crankshaft counterweights is called a "trunk" skirt. Who is right?

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

Question 41

Technician A says that conventional piston rings wear the bore more than low-tension rings. Technician B says low-tension rings must have less cylinder bore taper than conventional rings. Who is right?

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

Question 42

Two technicians are discussing pressed-fit piston pins. Technician A says that a pin press is used to remove piston pins. Technician B says that a rod furnace is used to remove piston pins. Who is right?

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

Question 43

Technician A says that all piston pins are offset from the centerline of the piston. Technician B says that most piston pins are pressed-fit in the connecting rod. Who is right?

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

Question 44

Technician A says that most V6s use offset connecting rods. Technician B says that rods that have been resized must use oversized rod bearings. Who is right?

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

Question 45

Technician A says the piston skirts are cam ground so piston to cylinder wall clearance is maintained as the piston expands with increasing engine temperature. Technician B says that piston skirts have slipper skirts to control expansion. Who is right?

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