Deck 5: Cylinder Components

Question 1

A piston's compression ring seals best during a(n) __________.

A)compression stroke
B)power stroke
C)intake stroke
D)exhaust stroke

Answer 1

A

Question 2

If an engine has a noise when it is cold but the noise disappears when the engine is warmed up, what is a likely cause of the noise?

A)A piston installed on the connecting rod is in the wrong direction.
B)An incorrectly installed piston skirt on an articulating piston.
C)Piston slap.
D)A loose connecting rod bushing.

Answer 2

C

Question 3

If an engine has 30% loss of crosshatch near the top of each cylinder, approximately what percentage of remaining service life does the engine have?

A)30%.
B)50%.
C)20%.
D)0%.

Answer 3

D

Question 4

Under which of the following conditions is the most engine slobber produced?

A)Idle conditions.
B)Light-load engine operation.
C)Full-load engine operation.
D)High-speed, light-load engine operation.

Question 5

Technician A says that when a diesel engine idles excessively, it will cause its cylinder walls to glaze and piston rings to stick. Technician B says idling an engine regularly for long periods of time causes piston rings to break. Who is correct?

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

Question 6

Technician A says that piston ring markings identify the type of ring and its location in a piston ring groove. Technician B says ring markings are used to ensure the rings are installed facing downward. Who is correct?

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

Question 7

Technician A says that after rebuilding an engine, the engine should be operated at low load and low speed to prevent any catastrophic damage. Technician B says that an engine should be operated under a heavy load as soon as possible after ring replacement. Who is correct?

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

Question 8

Technician A says that most high-horsepower (high-kilowatt) diesel engines use trunk-type pistons. Technician B says that most high-horsepower (high-kilowatt) diesel engines today use steel pistons. Who is correct?

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

Question 9

Technician A says a scuffed piston skirt and burned piston crown in one cylinder of a recently overhauled engine is likely due to a damaged or improperly aligned oil cooler nozzle. Technician B says the engine was overheated. Who is correct?

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

Question 10

While two technicians are discussing the cause of a cracked piston crown with a vertical crack through the inner edge of the combustion bowl, Technician A suggests that the piston has a manufacturing defect. Technician B suggests that using too much starting fluid cracked the piston. Who is correct?

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

Question 11

Which ring will cause excessive oil consumption if it is installed upside-down?

A)The compression ring.
B)The intermediate ring.
C)The oil control scraper ring.
D)Both the intermediate and compression rings.

Question 12

Which shape is most often used for compression rings in medium-duty diesel engines?

A)Square.
B)Rectangular.
C)Bevel faced.
D)Keystone.

Question 13

Which ring face material is used on compression rings to aid upper cylinder wall lubrication?

A)Steel.
B)Chrome.
C)Molybdenum.
D)Cast iron.

Question 14

Technician A says that oil control rings are designed to scrape as much oil as possible from the cylinder walls. Technician B says oil control rings leave a metered amount of oil on the cylinder walls. Who is correct?

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

Question 15

Technician A says compression rings in a diesel engine are rectangular to extend engine life. Technician B says that the top compression rings have a barrel face to provide effective sealing. Who is correct?

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

Question 16

Which of the following is the practice recommended to evaluate how well a diesel engine's piston rings seal?

A)A cylinder leak-down test.
B)A compression test.
C)A wet-dry compression test.
D)A measurement of the crankcase pressure.

Question 17

Where is a nickel insert used in an aluminum alloy piston used by diesel engines?

A)Pin boss.
B)Intermediate ring groove.
C)Skirt.
D)Compression ring groove.

Question 18

After discovering broken rings in an with more than a five thousand engine hours, Technician A says that the rings were most likely broken due to improper installation. After discovering the same broken rings in an engine, Technician B says the rings were broken due to excessive cylinder taper. Who is correct?

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

Question 19

Technician A says that a compression test of an engine's cylinders is the best method to use to diagnose a worn-out engine. Technician B says that measuring crankcase pressure is the best method to identify a worn-out engine. Who is correct?

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

Question 20

What kind of useful information is supplied by measuring the distance a piston protrudes above the cylinder block deck?

A)The amount of liner protrusion.
B)The length of the stroke.
C)Whether the connecting rod is bent.
D)The required thickness required for a head gasket.

Question 21

Which of the following are used in the pin boss for improved strength?

A)Expansion slots"
B)Oil jets"
C)Steel struts
D)Aluminum struts"

Question 22

What type of piston provides clearance for the turning radius of the crankshaft counterweights when the piston approaches bottom dead center (BDC)?

A)Slipper skirt"
B)Trunk type"
C)Articulating
D)Monosteel"

Question 23

What type of piston uses a full skirt?

A)Slipper skirt"
B)Trunk type"
C)Articulating
D)Monosteel"

Question 24

What type of piston uses less material between the piston crown and piston pin?

A)Slipper skirt"
B)Trunk type"
C)Articulating
D)Monosteel"

Question 25

The piston grooves are located in the:

A)crown"
B)top"
C)ring belt
D)skirt area"

Question 26

Trunk type pistons are used in more rugged applications of diesel engines such as inline-sixes with:

A)short-stroke design"
B)long-stroke design"
C)low horsepower output
D)high horsepower output"

Question 27

Final piston machining is done after trimming away the flashing or excess metal squeezed out between the halves of the mold called:

A)casting lines"
B)parting lines"
C)forge lines
D)control lines"

Question 28

What is the electrochemical process where aluminum is combined with oxygen to create a tough aluminum oxide finish?

A)Carbonizing"
B)Annealing"
C)Nitriding
D)Anodizing"

Question 29

Number four cylinder piston is burnt with scuff marks on it. Which of the following is the MOST LIKELY cause?

A)Incorrectly aimed nozzle"
B)Poor ring seal"
C)Overheated engine
D)Prolonged engine idling"

Question 30

One of the areas that experience the greatest wear is the top ring groove. The high combustion temperatures combined with ring movement in the top ring groove can cause rapid wear of this area. Which of the following is used to prevent this?

A)Chromium Rings"
B)N-Resist insert"
C)Cast iron insert
D)Steel compression ring"

Question 31

What area of the piston has the greatest amounts of expansion?

A)Crown"
B)Skirt"
C)Pin boss
D)Oil control ring"

Question 32

Diesel cylinder piston- to-wall clearance is being described. Technician A says that before installing piston rings, insert the inverted piston into a clean and properly honed or prepped cylinder. Technician B says that wear in the piston's ring groove dimensions are typically checked with a feeler gauge. Who is right?

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

Question 33

Which engine components wear faster than other internal engine parts, thus limiting engine life?

A)Rings"
B)Pistons"
C)Bearings
D)Valves"

Question 34

What minimizes power robbing blow-by which also leads to oil contamination and excessive crankcase emissions?

A)Springs"
B)High ring gap"
C)Gas tight sealing
D)Compression gas"

Question 35

Technician A says that ensuring long ring life is a function of service practices. Technician B says that rings must perform under extreme temperatures for the life of the engine. Who is right?

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

Question 36

Technician A says that when the rings are installed in the lands, you are ready to install the piston. Technician B says piston rings that are not properly aligned can result in oil consumption. Who is right?

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

Question 37

Which of the following refers to the ring's ability to operate with as little friction as possible?

A)Compatibility"
B)Embedability"
C)Friction ability
D)Sealing ability"

Question 38

Two technicians are discussing piston rings. Technician A says that piston rings form a gas tight seal between the piston and the cylinder wall. Technician B says that oil control rings can be installed by hand with no special tools. Who is right?

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

Question 39

What rings are located nearest the piston crown?

A)Compression"
B)Intermediate"
C)Oil control
D)Secondary"

Question 40

What type of piston ring is usually cast iron with scraper rails that remove excess oil from the cylinder wall while leaving a metered quantity for lubricating the cylinder wall?

A)Compression"
B)Intermediate"
C)Oil Control
D)Secondary"

Question 41

Low-tension rings can significantly increase:

A)fuel consumption"
B)fuel economy"
C)carbon monoxide emission
D)oxides of nitrogen emission"

Question 42

Two technicians are describing ring gap. Technician A says that too large a ring gap will cause the ends to butt and prevent expansion. Technician B says that too little of a gap will obviously cause a loss of compression and excessive blow-by. Who is right?

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

Question 43

What is the compression ring shape of choice for most engine manufacturers?

A)Square"
B)Keystone"
C)Barrel
D)Oval"

Question 44

What is used to stretch a ring just far enough to allow its removal but not too far to cause it to bend or break?

A)Ring expanders"
B)Small pry bar"
C)Snap ring pliers
D)Ring installers"

Question 45

When doing a cylinder leak-down test, which of the following must be done?

A)Cylinder tested at TDC"
B)Cylinder tested at BDC"
C)Air compressed at no more than 30 psi
D) Air compressed at no more than 50 psi

Question 46

If all the cylinders have low compression but show minimal leakage, the most likely cause is:

A)defective rings"
B)burnt valve"
C)defective turbocharger
D)engine timing off"

Question 47

What will produce an abnormally high crankcase pressure reading?

A)Cold engine"
B)Hot engine"
C)Engine at high idle
D) Engine at full fuel

Question 48

Which of the following tools is used to measure cylinder taper?

A)Outside micrometer"
B)Feeler gauge"
C)Vernier caliper
D)Dial bore gauge"

Question 49

Cylinder taper and out-of-round conditions are evaluated by measuring a cylinder dimensions with a dial bore gauge or:

A)the ring end gap method"
B)an outside micrometer and bore gauge"
C)a small hole gauge and expansion tool
D) a vernier caliper

Question 50

Which of the following is the practice recommended to evaluate how well a diesel engine's piston rings seal?

A)A cylinder leak-down test."
B)A compression test."
C)A wet-dry compression test.
D)A measurement of the crankcase pressure."

Question 51

What type of pin is held in place by spring clips or in the instance of some newer engines, Teflon caps?

A)Non-floating pin"
B)Circlip pin"
C)Full floating pin
D)Semi-floating pin"

Question 52

Some wrist pins use a(n) ______ where the pin bore will increase in diameter with temperature in a running engine to allow the pin to move freely on both piston and con-rod?

A)press-fit"
B)interference fit"
C)loose Fit
D)controlled fit"

Question 53

Lower cylinder pressures allow the use of:

A)solid pins"
B)brass pins"
C)chrome pins
D)hollow pins"

Question 54

Two technicians are discussing side thrust. Technician A says that the piston pin axis offset from the cylinder centerline eliminates noises caused by the rocking of the piston. Technician B says that to minimize the degree of side thrust, engine manufacturers often offset the centerline of the wrist pin with the centerline of the piston. Who is right?

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

Question 55

Clearances between the sides of the piston instantly switch from one side to the other side as the piston moves:

A)through TDC"
B)through BDC"
C)through mid-stroke
D) 10 degrees after TDC

Question 56

Connecting rod tensional loading occurs at the end of the up-strokes at:

A)BDC"
B)TDC"
C)mid-stroke
D)10 degrees after TDC"

Question 57

What process is used on connecting rods to relieve stress risers and add additional fatigue strength?

A)Haber"
B)Nitriding"
C)Shot-peening
D)Knurling"

Question 58

When the small end is shaped like a triangle, it is called a(n) _____rod.

A)triangle"
B)I-Beam"
C)H-Beam
D)tee-pee"

Question 59

Which of the following is NOT an advantage of using a fracture split rod cap?

A)Improved control of oil clearances"
B)Reduced production costs"
C)More precise alignment of the rod and cap
D)Less retention strength"

Question 60

One common feature is that connecting rod ends can have an offset or split of the rod cap of ____ degrees.

A)10 to 15"
B)25 to 40"
C)45 to 90
D)45 to 60"