Construction Of An Internal Combustion Engine

Front 1

Gasoline and diesel engines are alike in what respect?

Back 1

Both have the same basic internal components

Front 2

What is the function of the stationary parts of an engine?

Back 2

Furnish a framework on which to
attach or enclose moveable parts

Front 3

Which of the following parts provides a basic frame for the liquid-cooled engine used in automotive and construction equipment?

Back 3

Cylinder block

Front 4

T/F Aluminum cylinder blocks are cheaper to produce than cast iron cylinder blocks.

Back 4

False

Front 5

An engine block with newly bored cylinders may not vary in diameter by more than

Back 5

0.0005 in.

Front 6

The cylinders of an air-cooled engine are separate from the crankcase and made of what material?

Back 6

Forged steel

Front 7

The purpose of the fins surrounding the cylinders of an air-cooled engine is to provide

Back 7

a large surface area for heat dissipation

Front 8

What is the function of the cylinder liners in an engine?

Back 8

To provide a wearing surface other
than the engine block

Front 9

What is the purpose of the interconnecting passages in the cylinder head and block?

Back 9

To provide a path for the coolant to circulate

Front 10

What part of the air-cooled engine provides the mounting surface for the cylinders and oil pump?

Back 10

Crankcase

Front 11

T/F On an air-cooled engine, the cylinder heads are made of aluminum to resist corrosion.

Back 11

False

Front 12

The stationary part of an internal combustion engine that carries waste gases of combustion from the cylinders is called

Back 12

exhaust manifold

Front 13

T/F The intake manifold of a gasoline engine is designed to provide the fuel with a short and direct path between the carburetor or fuel injection system and the cylinder. This design reduces the possibility of the air- fuel mixture condensing in the intake manifold.

Back 13

True

Front 14

What valve controls the amount of exhaust diverted into the intake manifold heat passage in an exhaust-heated intake manifold?

Back 14

Manifold heat control

Front 15

A gasket is placed between the cylinder head and engine block to

Back 15

prevent gas and water leaks

Front 16

From what material are the gaskets for intake and exhaust manifolds usually constructed?

Back 16

Asbestos

Front 17

Of what type of material are oil pan gaskets usually made?

Back 17

Pressed cork

Front 18

In modem engines, fluid losses through clearances between moving parts and stationary parts are prevented by the use of

Back 18

oil seals

Front 19

In an engine, heat energy is changed to mechanical energy by the pressure of combustion acting on the

Back 19

pistons

Front 20

The downward motion of the piston in the cylinder is converted to rotary motion by the action of the

Back 20

connecting rod and crankshaft

Front 21

What design feature is the principal difference between a diesel engine piston and a gasoline engine piston?

Back 21

Diesel engine pistons are usually fitted with more piston rings than gasoline engine pistons

Front 22

What feature is built into pistons to control expansion?

Back 22

A slot is cut up the side of the skirt

Front 23

What are the two types of piston skirts?

Back 23

Full trunk and partial skirted

Front 24

The piston pin (wrist pin) attaches the piston to what component?

Back 24

The connecting rod

Front 25

In addition to sealing off the combustion chamber and distributing lubricating oil, piston rings serve to

Back 25

transfer heat from the pistons to the cylinder walls

Front 26

The additional groove cut into a piston just above the top ring groove is known as a

Back 26

heat dam

Front 27

The split in the piston ring is necessary for installing the ring on the piston and for expansion from heating. This split is known as a

Back 27

ring gap

Front 28

Piston rings are staggered during assembly to

Back 28

prevent cylinder blow-by

Front 29

Piston rings are coated with what material to minimize scuffing?

Back 29

Graphite, phosphate or molybdenum

Front 30

During engine operation, thrust from the piston is transmitted to the crankshaft by what component?

Back 30

The connecting rod

Front 31

What type of bearing is used in the piston end of the connecting rod?

Back 31

Bushing

Front 32

Precision connecting rod bearings are held in position against the crankshaft by

Back 32

projection on the bearing shells

Front 33

The crankshaft of a military engine is normally constructed of what material?

Back 33

Forged steel

Front 34

On an in-line six-cylinder engine, the crankshaft throws are set apart by how many degrees?

Back 34

120°

Front 35

What is the function of the counterweights on a crankshaft?

Back 35

To balance the weight of the connecting rod and piston

Front 36

The purpose of thrust faces found on some main bearings is to

Back 36

prevent crankshaft vibration

Front 37

What type of vibration occurs when the crankshaft twists because of the power stroke?

Back 37

Torsional vibration

Front 38

What part of an engine is likely to fail when subjected to uncontrolled torsional vibrations?

Back 38

Crankshaft

Front 39

In addition to reducing engine speed fluctuations, the flywheel often serves as a

Back 39

pressure surface for the clutch and starting system gear

Front 40

Which of the following components does not help to make up the valve-actuating mechanism?

Back 40

Crankshaft

Front 41

What is the function of the camshaft?

Back 41

To operate the valve mechanism

Front 42

On what type of engine head is the camshaft usually located directly above the crankshaft?

Back 42

V

Front 43

The camshaft of a two-stroke cycle engine will rotate at what speed when the crankshaft speed is 1,000 rpm?

Back 43

1,000 rpm

Front 44

T/F The camshaft may have external gears or cams that operate the fuel injectors, lubrication pump, and fuel pump.

Back 44

T

Front 45

What type of mechanical follower (tappet) is used in heavy-duty applications?

Back 45

Roller

Front 46

How is zero clearance maintained by the hydraulic type tappet shown in figure 3-48 in the text?

Back 46

By oil pressure

Front 47

Poppet-type valves are designed in which of the following shapes?

Back 47

1. Mushroom
2. Tulip
3. Semitulip

Front 48

Because the exhaust valves of an engine can experience temperatures in excess of
1300°F, the valve IS normally made of what type of alloy?

Back 48

Silichrome

Front 49

In vehicles that use unleaded -fuel. the wear of the valve face and seat IS accelerated. What type of valve is used to decrease wear and prolong the life of the valve?

Back 49

Stellite

Front 50

An accumulation of carbon on valve seats will result in what problem?

Back 50

Improper valve closure

Front 51

Valve seat inserts used in aluminum engines are made of what material to withstand the extreme heat produced’?

Back 51

Steel

Front 52

The close clearance between the valve guide and the valve stem is important for which of the following reasons?

Back 52

Keeps the valve face in alignment with the valve seat

Front 53

Valve float is caused by which of the following conditions?

Back 53

Low spring tension

Front 54

Valve reconditioning include which of the following?

Back 54

1. Grinding valves and valve seats
2. Adjusting valve tappet clearance
3. Timing the valves

Front 55

What part of the engine must be removed before the valves are accessible’?

Back 55

Cylinder head

Front 56

During reassembly of an engine, replacing the valves in their original guides will ensure

Back 56

less wear of the valve and guide

Front 57

T/F The difference between valve seat angle and valve face angle is known as interference angle.

Back 57

T

Front 58

One procedure for checking valve guide wear involves the use of what instrument(s)?

Back 58

A hole gauge and micrometer

Front 59

What procedure is used to compensate for valve guide wear?

Back 59

Knurling

Front 60

Once the valve guides are serviced and the valve seats are ground, the concentricity of the two are checked using what measuring instrument?

Back 60

Valve seat dial indicator

Front 61

T/F When replacing pressed-in valve seats, you should chill the new inserts in dry ice for
15 minutes.

Back 61

T

Front 62

When the valve seat does not touch the valve face properly, the seat must be reground at different angles. This procedure is known as

Back 62

narrowing a valve

Front 63

Which of the following checks are to be made on valve springs before reassembling them?

Back 63

Squareness
Free height
Tension

Front 64

Which of the following actions is a step in
the procedure for installing the directly
driven timing gears on an engine?

Back 64

Position the gears so that the single
marked tooth of one gear is between
the two marked teeth of the other gear

Front 65

Oil moving across the face of a bearing
accomplish which of the
following functions?

Back 65

Cools the bearing
Lubricates the bearing
Removes dirt from the bearing

Front 66

The back of the typical bearing half is
made of what bearing?

Back 66

Steel

Front 67

Which of the following metal alloys is not
plated on the back of a typical bearing
halt?

Back 67

Bronze

Front 68

What test is the most often used to
determine the mechanical condition of an
engine?

Back 68

Compression

Front 69

T/F When a compression test is performed on a
gasoline engine, the compression reading
from the highest to the lowest cylinder
should not vary over 15 to 20 psi.

Back 69

T

Front 70

When a vacuum test is performed above
1,000 feet, the average reading will lose
approximately what amount of inches of
vacuum per 1,000 feet?

Back 70

1 IN

Front 71

When a vacuum test is being performed,
the gauge drops to 15 inches and remains
there. This reading indicates the existence
of what problem?

Back 71

Compression leak between the
cylinder walls and the piston rings

Front 72

When performing a cylinder leakage test,
you must ensure the piston is at what
position’?

Back 72

TDC

Front 73

When a cylinder leakage test is performed,
a leaking head gasket is indicated by which
of the following conditions?

Back 73

Bubbles in the coolant at the radiator

Front 74

What material is commonly used to provide a
wearing surface in a liquid-cooled engine for the
pistons to ride against?

Back 74

cylinder sleeves or liners

Front 75

What are the two types of cylinder sleeves?

Back 75

wet- and dry-type

Front 76

What are the two types of core hole plugs used in
an internal combustion engine?

Back 76

cup and disk

Front 77

What is the basic foundation of all air-cooled
engines ?

Back 77

crankcase

Front 78

A properly made exhaust manifold results in
what type of action to help an engine get rid of
exhaust gases?

Back 78

scavenging

Front 79

In an exhaust-heated intake manifold, gases
diverted to the manifold are controlled by what
valve?

Back 79

manifold heat control valve

Front 80

What two basic types of oil seals are currently
being used on engines?

Back 80

synthetic rubber and wick

Front 81

What ate the structural components of a piston?

Back 81

head, skirt, ring grooves, and lands

Front 82

What are the three types of piston pin
configurations?

Back 82

anchored, semi-floating, full-floating

Front 83

What three functions do piston rings serve?

Back 83

provide a seal between piston and cylinder wall, contains lubricating oil,
and provides a solid bridge to conduct heat from piston to cylinder wall

Front 84

What part is the backbone of an internal
combustion engine?

Back 84

crankshaft

Front 85

The valve actuating mechanism is made up of
what engine parts?

Back 85

camshaft, followers, pushrods, and rocker arms

Front 86

What are the three basic shapes of a poppet-type
valve ?

Back 86

mushroom, semi-tulip, and tulip

Front 87

What type of valve is preferred in a vehicle using
unleaded fuel?

Back 87

stellite

Front 88

What are the two basic types of valve seals?

Back 88

umbrella and O ring

Front 89

What three characteristics of a valve spring
should you check?

Back 89

spring squareness, spring free height, and spring tension

Front 90

Overhead valves are adjusted with the engine in
what condition ?

Back 90

normal operating temperature

Front 91

When you perform a wet compression test and
the reading goes up, what is the most likely
problem?

Back 91

piston rings and cylinders may be worn and leaking pressure

Front 92

You make a vacuum gauge test at sea level with
the engine idling at 550 rpm, and you get a
reading of 10 inches. What is the most probable
cause?

Back 92

incorrect timing

Front 93

When performing a cylinder leakage test, you
notice a loud hissing of air from the carburetor.
This is an indication of what type of problem?

Back 93

leaking intake valves