Deck 12: Upper-End Theory and Service

Question 1

Stainless steel is nonmagnetic.

Answer 1

True

Question 2

Multiple valve engines tend to be more efficient than engines with two valves per cylinder because:

A)larger valve area improves the air flow.
B)air velocity is increased.
C)less engine power is lost to spring opening drag.
D)All the answers are correct.

Answer 2

D

Question 3

Which of the following statements about knurling is false?

A)It is one of the fastest techniques for restoring the inside diameter dimension of a worn valve guide
B)Using oversize valve stems is superior to knurling.
C)It is useful for restoring badly worn guides to their original condition.
D)It doesn't change the centerline of the valve stem.

Answer 3

C

Question 4

The hemispherical combustion chamber provides excellent turbulence to the air and fuel mixture.

Question 5

A single hole in the cylinder head that divides into two branches is called a _____ port.

A)dual
B)siamese
C)combination
D)two-stage

Question 6

Resurfacing a cylinder head gasket surface may alter the combustion chamber volume.

Question 7

In response to temperature changes, aluminum expands and contracts almost twice as much as cast iron.

Question 8

Powder metal valve seats are softer and do not last as long as cast iron seats.

Question 9

Sodium-filled valves should be cut open for inspection.

Question 10

What is typically the maximum amount of warpage that is acceptable on a cast-iron cylinder head?

A)0.002 in. (.05 mm)
B)0.003 in. (.076 mm)
C)0.004 in. (.1016 mm)
D)0.005 in. (.127 mm)

Question 11

To protect against scuffing and wear, some valves have coatings of black nitride applied to the valve stem.

Question 12

The performance of an engine, its fuel efficiency, and its exhaust emissions all depend to a large extent on the shape of the combustion chamber.

Question 13

Valve springs should be checked for all of the following EXCEPT:

A)freestanding height
B)squareness
C)compressed height
D)open pressure

Question 14

To ensure proper seating of the valve, the valve seat must _____.

A)be the correct width
B)have the correct location on the valve face
C)be concentric with the guide
D)All the answers are correct.

Question 15

Technician A says worn valve stem seals can increase oil consumption. Technician B says worn valve stem seals can cause valve deposits. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 16

Technician A says positive valve stem seals fit loosely around the top of the stem. Technician B says positive stem seals scrape oil off the valve as it moves up and down. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 17

A cylinder head may be made of cast iron or aluminum.

Question 18

Aluminum cylinder heads weigh roughly half as much as cast-iron heads.

Question 19

Aluminum cylinder head bolts should never be loosened or tightened when the metal is hot.

Question 20

Many camshaft journals run directly on aluminum supports and do not use bearing inserts.

Question 21

____________________ is a very rapid movement of gases that causes the air and fuel to mix better and improve combustion.

Question 22

Resurfacing the cylinder head can affect _____.

A)compression ratio
B)valve timing
C)piston to valve clearance
D)All the answers are correct.

Question 23

A pentroof combustion chamber is normally found on a(n)_____type cylinder head.

A)OHV
B)four valve per cylinder
C)two valve per cylinder
D)VVT (variable valve timing)

Question 24

Technician A says if valve stem height exceeds specifications, it can be adjusted by grinding the valve tip. Technician B says the valve stem height can be adjusted with shims. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 25

Technician A says the end of the valve spring that is wound the tightest should face toward the spring retainer. Technician B says the O-ring seal should be installed in the lowest of the keeper grooves on the valve stem.

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 26

_____type valve stem seals move up and down with the valve stems to deflect oil away from the guides.

A)Positive
B)Umbrella
C)O-ring
D)Lip

Question 27

Installed spring height [the distance between the spring seat and the bottom of the retainer] can be measured with a spring height gauge or ____________________.

Question 28

Technician A says multivalve engines can have two valves per cylinder. Technician B says multivalve engines must have five valves per cylinder. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 29

Hemispherical combustion chambers are being discussed. Technician A says the flame path from the spark plug to the piston head is long, which provides efficient burning. Technician B says the cross-flow arrangement of the inlet and exhaust valves allows for a free flow of gases in and out of the chamber. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 30

Technician A says VVT (variable valve timing)engines use a cam phaser that advances or retards the camshaft as the engine is running. Technician B says VVT engines use a third cam lobe with increased lift and duration, operating a third rocker arm that is coupled to the two primary rocker arms by a hydraulically controlled pin, while the engine is running. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 31

Technician A checks for bent pushrods by rolling them on a flat surface. Technician B checks for bent pushrods using a dial indicator and V-blocks. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 32

Technician A says multivalve engines have a more complete combustion than conventional engine designs. Technician B says the benefits of multivalve engines may be offset by a more complicated camshaft arrangement. Who is correct ?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 33

Technician A says heat is transferred from an exhaust valve to the cylinder head through the valve seat. Technician B says some exhaust valves have a hollow stem filled with silicone to transfer heat to the valve guide. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 34

Valve guides are _____.

A)integral (bores in cylinder head)
B)pressed in cast iron inserts
C)pressed in bronze inserts
D)All the answers are correct.

Question 35

Technician A resurfaces valve seats using a grinding stone. Technician B resurfaces valve seats using a cutting blade. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 36

The type of valve used in automotive engines is called a ____________________.

Question 37

____________________ support the valve in the head and prevent the valve from moving in any direction other than up and down.

Question 38

Cylinder head warpage can be measured with _____.

A)a straightedge and feeler gauge
B)a dial indicator
C)a surface gauge
D)a ball gauge and outside micrometer

Question 39

Prussian blue or machinist dye is used to ______.

A)measure stem-to-guide clearance
B)measure valve runout
C)mark the position of cam bearings prior to removal
D)check the width and position of the valve-to-seat contact pattern

Question 40

After resurfacing a valve seat at 45 degrees, the seat is too wide and the contact pattern extends all the way up to the valve margin. What should be done to bring the seat width into specifications?

A)Make a 30-degree topping cut
B)Make a 45-degree seat cut
C)Make a 60-degree throat cut
D)Replace the valve

Question 41

How does refinishing a valve face and the valve seat affect its position in the cylinder head?

Question 42

The camshafts and timing gears are removed from the cylinder head. A technician covers the return oil holes in a camshaft with electrical tape and applies compressed air to the other oil hole. With the camshaft held stationary, the timing gear rotates a few degrees counterclockwise. When the air pressure is released, the timing gear rotates clockwise back to its original position. This proves that the ____________________ is working properly.

Question 43

Describe a hemispherical combustion chamber.

Question 44

What is the most common cause of warpage in an aluminum cylinder head?

Question 45

Installed valve spring height can be adjusted with ____________________.

Question 46

Why does a properly finished valve seat have three different angles?

Question 47

While disassembling a cylinder head, what would indicate that the valve seals are worn or damaged?

Question 48

The distance between the valve face and the head of the valve is called the ____________________.

Question 49

What is the function of a rocker arm?

Question 50

What procedures should be followed after refinishing a valve face?

Question 51

Valve stem wear may be measured with a ____________________.

Question 52

Describe a phaser.

Question 53

Where on the cylinder head are cracks most likely to occur?

Question 54

What happens when valve spring tension is too low?

Question 55

A cylinder head that has the intake manifold and all the intake valves on one side and the exhaust manifold and exhaust valves on the opposite side is called a ____________________type cylinder head.

Question 56

The surface of a valve that comes into contact with the valve seat is called the valve ____________________.