Engines - Exhaust, Cooling, Lubrication and Ventilation

Question 1

What are the main components of an exhaust system?

Answer 1

Exhaust manifold, piping, silencer

These components work together to collect and remove exhaust gases from the engine.

Question 2

What is the primary function of an exhaust system?

Answer 2

To collect and remove exhaust with minimum restriction and adequate silencing

This function is essential for engine performance and compliance with emission standards.

Question 3

What role does the muffler play in the exhaust system?

Answer 3

Reduces noise from pulsations in the exhaust system

The muffler achieves noise reduction through the flow path of gas inside it.

Question 4

True or False: Catalytic converters are optional in exhaust systems.

Answer 4

False

Catalytic converters are often necessary to comply with government exhaust emission standards.

Question 5

What feature is commonly found on mufflers of stationary engines to prevent water entry?

Answer 5

Rain cap

The rain cap helps to protect the exhaust system from water damage.

Question 6

What is the purpose of flexible pipe unions in an exhaust system?

Answer 6

Allow for thermal expansion and reduce vibration transfer

These unions help maintain the integrity of the exhaust system under varying conditions.

Question 7

Fill in the blank: The exhaust system carries gases from the cylinder-head exhaust ports to the exhaust _______.

Answer 7

manifold

The exhaust manifold is the first component that collects the exhaust gases.

Question 8

What is the significance of having minimum backpressure in a muffler?

Answer 8

To ensure efficient engine operation

Minimum backpressure helps maintain optimal exhaust flow and engine performance.

Question 9

List the two methods mentioned for preventing water entry into the exhaust system.

Answer 9

• Rain cap
• Exhaust pipe cut on an angle

Both methods are designed to mitigate water-related issues in exhaust systems.

Question 10

What is the final destination of exhaust gases in an exhaust system?

Answer 10

Discharges into the atmosphere

This is the last step in the exhaust system’s function, allowing gases to exit safely.

Question 11

Explain the function of a catalytic converter in an exhaust system.

Answer 11

To reduce harmful emissions before they exit into the atmosphere

Catalytic converters play a critical role in meeting environmental regulations.

Question 12

What should be performed before removing or replacing components in the exhaust system?

Answer 12

A thorough inspection and diagnosis of the entire system

This includes visual inspection, backpressure and temperature checks, and removal of the exhaust manifold.

Question 13

What are the key elements to inspect during a visual inspection of the exhaust system?

Answer 13

• Holes and leaks
• Rust
• Loose components
• Improperly positioned heat shields

These elements can indicate physical damage that needs to be addressed.

Question 14

What effect does backpressure have on an engine?

Answer 14

Reduces the engine’s ability to breathe, resulting in a loss of power or engine stall if high enough

High backpressure can indicate issues within the exhaust system.

Question 15

What tool is recommended for checking backpressure in the exhaust system?

Answer 15

A mercury manometer

It should be used as close to the engine exhaust manifold as possible.

Question 16

What is the acceptable level of exhaust backpressure for most applications?

Answer 16

1 psi or less

Levels above this may indicate an internally collapsed muffler or exhaust pipe.

Question 17

How can you verify if a catalytic converter is functioning properly?

Answer 17

The temperature at the outlet should be at least 38°C (100°F) greater than the temperature at the inlet

A properly functioning converter generates heat during the reaction process.

Question 18

What happens to exhaust manifolds during heating and cooling cycles?

Answer 18

They go through stress and corrosion

This can affect their integrity and sealing capability.

Question 19

What is a common issue when removing an exhaust manifold?

Answer 19

It usually distorts slightly, making it no longer flat enough to seal without a gasket

Gaskets are used to eliminate leaks when reinstalling the manifold.

Question 20

Fill in the blank: Exhaust backpressures should be _______ for most applications.

Answer 20

1 psi or less

Question 21

True or False: A properly functioning catalytic converter does not generate heat.

Answer 21

False

A properly functioning catalytic converter generates heat in the reaction process.

Question 22

Why is it recommended to use a water manometer instead of a mercury manometer on the intake side of an engine?

Answer 22

The vacuum can be high enough to suck the fluid into the intake;

While not good, water is better than mercury

Question 23

What is the main function of the engine cooling system?

Answer 23

To regulate engine temperature

This ensures optimal engine efficiency and longevity.

Question 24

What are the three methods used by the cooling system to reject heat?

Answer 24

• Conduction
• Convection
• Radiation

These methods help maintain appropriate engine temperatures.

Question 25

Define conduction in the context of an engine cooling system.

Answer 25

The transfer of heat from molecule to molecule, occurring when heat from the block, heads, and liners transfers to the coolant. ## Footnote This process is essential for heat management in the engine.

Question 26

What is convection in the cooling system?

Answer 26

The transfer of heat by movement of a medium such as coolant and air. ## Footnote It involves circulating coolant with the water pump and/or moving air through the heat exchanger.

Question 27

Explain radiation in the context of heat transfer.

Answer 27

The transfer of heat through space by electromagnetic waves from one object to another. ## Footnote The sun is an example of radiant heat transfer.

Question 28

What is the optimal temperature range for most engines?

Answer 28

82°C to 95°C (180°F to 200°F) ## Footnote Maintaining this range is crucial for engine performance.

Question 29

What six problems can arise from engine overheating?

Answer 29

* Pre-ignition * Detonation * Burnt pistons * Burnt valves * Scored liners * Lube oil breakdown ## Footnote These issues can lead to severe engine damage.

Question 30

What are four consequences of running an engine below the optimal temperature range?

Answer 30

* Sludge accumulation * Water accumulation in the crankcase * Poor fuel economy * Unnecessary engine wear ## Footnote These issues can degrade engine performance and longevity.

Question 31

Fill in the blank: The cooling system prevents both _______ and _______ which are harmful.

Answer 31

overheating, overcooling ## Footnote Both conditions can lead to engine failure.

Question 32

True or False: Running an engine at too low a temperature can cause sludge and water accumulation.

Answer 32

True ## Footnote This can negatively affect engine performance.

Question 33

What can happen if a thermostat fails or is missing?

Answer 33

The engine will run too cool ## Footnote This can lead to various engine issues.

Question 34

True or false: Water is a byproduct of-product of combustion.

Answer 34

True; This is why it is important to ensure the engine temp remains high enough to boil off the water, preventing it from collecting in the oil

Question 35

What are the primary components of an air-cooled engine cooling system?

Answer 35

Fins on cylinders and heads, forced-air fan, shrouding, and baffles ## Footnote The fins increase surface area to facilitate heat removal.

Question 36

How does the airflow in an air-cooled engine cooling system help regulate temperature?

Answer 36

By directing airflow to hot points using shrouding and baffles ## Footnote Temperature regulation can also involve a thermostatic valve.

Question 37

What distinguishes an open liquid cooling system from a closed liquid cooling system?

Answer 37

In an open system, coolant is not recirculated and is sourced from external water supplies ## Footnote This includes city water utilities, reservoirs, or lakes.

Question 38

What is the primary function of the radiator in a closed liquid cooling system?

Answer 38

To reject heat from the recirculated coolant ## Footnote This allows for conditioning of the coolant to minimize scale buildup.

Question 39

What role does the water pump play in a closed liquid cooling system?

Answer 39

Creates coolant flow ## Footnote It is essential for maintaining circulation within the system.

Question 40

Which component regulates the flow of coolant to the heat exchanger in a closed liquid cooling system?

Answer 40

Thermostat ## Footnote The thermostat ensures optimal temperature control.

Question 41

List the main parts of a cooling system.

Answer 41

* Water pump and drive * Water jackets * Thermostat * Radiator or heat exchanger * Radiator cap * Expansion or surge tank * Fans and fan drives * Coolant filters * Water manifolds, hoses, and lines * Coolant ## Footnote These components work together to manage engine temperature.

Question 42

True or False: The closed liquid cooling system is the most common type used in engines.

Answer 42

True ## Footnote This system allows for efficient heat dissipation and coolant reuse.

Question 43

Fill in the blank: The coolant in a closed liquid cooling system is _______ to allow for a minimum of scale buildup.

Answer 43

recirculated ## Footnote This process helps prolong the life of the cooling system.

Question 44

What additives are used in coolant to reduce cavitation damage on liners?

Answer 44

* Chromates * Nitrates ## Footnote These additives help protect engine components from wear.

Question 45

What is the primary function of the water pump in the cooling system?

Answer 45

To create a continuous flow in the cooling system, even when the thermostat is closed. ## Footnote This helps to circulate coolant to the hottest part of the engine.

Question 46

What type of pump is a water pump in automotive engines?

Answer 46

Centrifugal, non-positive, displacement-type pump. ## Footnote These pumps are driven by the engine.

Question 47

How can water pumps be driven in an engine?

Answer 47

By belts, chains, or gears. ## Footnote These drive mechanisms are essential for the operation of the water pump.

Question 48

What is the purpose of the thermostat in the cooling system?

Answer 48

To sense engine temperature and maintain operating limits by controlling coolant flow. ## Footnote It helps to direct coolant either to the radiator or back to the water pump.

Question 49

What is the common design of a thermostat used in engines?

Answer 49

Wax pellet type. ## Footnote It uses wax confined in a copper pellet that expands when heated to open the thermostat valve.

Question 50

What is the role of the bypass tube in the cooling system?

Answer 50

To reduce warm-up time and prevent the cylinder head from overheating when the thermostat is closed. ## Footnote It allows coolant to recirculate back to the engine.

Question 51

True or False: The coolant discharged from the pump enters the block and flows through a distribution passage.

Answer 51

True. ## Footnote This distribution passage can be cast into the block or piped to an outside water manifold.

Question 52

Fill in the blank: Always install a thermostat with the temperature sensor facing _______.

Answer 52

toward the engine. ## Footnote Proper installation is crucial for the thermostat to function correctly.

Question 53

What happens to larger engines regarding thermostat design?

Answer 53

They may have more than one thermostat to allow for a large volume of coolant flow. ## Footnote Some large engines with individual cylinder heads may have a thermostat on each head.

Question 54

What is the significance of the water pump's continuous flow?

Answer 54

It ensures that the top part of the engine, which may be the hottest, remains cooled. ## Footnote This is critical for engine performance and longevity.

Question 55

What component is used to reject heat from the engine in a cooling system?

Answer 55

Radiator or heat exchanger ## Footnote The radiator also acts as a reservoir for the coolant in a closed loop system.

Question 56

What is the function of the radiator cap in a cooling system?

Answer 56

Regulates system pressure above atmospheric pressure | Allows pressure to build in the system. ## Footnote This increase in pressure raises the boiling point temperature of the coolant.

Question 57

True or False: The radiator cap has a vacuum valve to allow the system to draw in air when the coolant contracts.

Answer 57

True ## Footnote Without the vacuum valve, the hoses on the heat exchanger would collapse when the engine cools off.

Question 58

What is the purpose of the expansion or surge tank in a cooling system?

Answer 58

Fills coolant, allows expansion, and de-aerates coolant ## Footnote It must be above the engine and has vent lines to eliminate air or steam pockets.

Question 59

Where must an expansion tank be located on an engine?

Answer 59

Above it ## Footnote It must be above the engine and has vent lines to eleiminate air or steam pockets.

Question 60

What drives the fan in small engines?

Answer 60

Belt-driven fan attached to the water pump ## Footnote Similar to the design on mobile equipment.

Question 61

In large stationary engines, how is the fan typically driven?

Answer 61

Long belt-driven fan shaft attached to the front of the engine ## Footnote The fan is outside the building, and no air from the fan moves past the engine.

Question 62

What type of fans may be used in some cooling systems?

Answer 62

Electric fans ## Footnote These fans are activated by temperature switches.

Question 63

What is the role of coolant filters in a cooling system?

Answer 63

Keeps the cooling system clean and extends the life of water pump seals and liner O-rings ## Footnote Effective in maintaining the system's cleanliness.

Question 64

Fill in the blank: The increase in system pressure by 1 psi can raise the boiling point of the coolant by _____ degrees.

Answer 64

3 ## Footnote This means a 10 psi increase would raise the boiling point of to 242°F from 212°F.

Question 65

What is the typical micron size for coolant filters?

Answer 65

15 - 25 microns ## Footnote This specification helps maintain the cleanliness of the cooling system.

Question 66

Which component of an engine coolant system builds pressure within the system?

Answer 66

The radiator cap

Question 67

What is the primary advantage of using steel pipe with flexible rubber couplings over rubber hoses in industrial applications?

Answer 67

More durable ## Footnote Steel pipes are preferred because they are less prone to damage and wear compared to rubber hoses.

Question 68

What percentage more heat does water absorb compared to mixed glycols?

Answer 68

Approximately 15% ## Footnote Water's heat absorption capacity makes it an effective coolant.

Question 69

What are the boiling and freezing temperatures of water?

Answer 69

100°C (212°F) and 0°C (32°F) ## Footnote These temperatures are critical in determining the effectiveness of water as a coolant.

Question 70

What happens to water when it freezes, and how can this affect the engine?

Answer 70

It expands, potentially cracking the engine block and cylinder heads ## Footnote Expansion can also damage the radiator and heater core.

Question 71

What are the two main types of antifreeze products used in engine coolants?

Answer 71

Ethylene glycol and propylene glycol ## Footnote These compounds are commonly used due to their effective thermal properties.

Question 72

What is the recommended mixture for engine coolant to provide optimal boiling and freezing point protection?

Answer 72

50/50 solution of distilled water and antifreeze ## Footnote This mixture balances the boiling and freezing points for better performance. Left = boiling point, right = freezing point

Question 73

What is a key disadvantage of ethylene glycol based coolant?

Answer 73

It is toxic and hazardous to the environment ## Footnote Despite its high boiling point, its toxicity is a significant concern.

Question 74

What is a notable advantage of propylene glycol based coolant over ethylene glycol?

Answer 74

It is non-toxic and less hazardous to the environment ## Footnote This makes it a safer option for various applications.

Question 75

What is a disadvantage of propylene glycol based coolant?

Answer 75

Lower boiling point than ethylene glycol and can react with some materials ## Footnote This limits its effectiveness in certain situations.

Question 76

What is the boiling point of waterless coolant, and what is its main benefit?

Answer 76

Boils at 375°F, no corrosion ## Footnote Waterless coolant is gaining popularity due to its ability to prevent corrosion and operate at higher temperatures.

Question 77

Fill in the blank: The engine coolant must remain ______ even when the outside temperature drops below freezing.

Answer 77

liquid ## Footnote Maintaining a liquid state is crucial for effective cooling.

Question 78

What happens when glycol is introduced into the lubrication system?

Answer 78

The oil/glycol mixture becomes acidic, damaging engine bearings, increasing oil viscosity, and corroding engine component surfaces. ## Footnote Glycol can lead to significant mechanical failures if not managed properly.

Question 79

What is scale in the context of cooling systems?

Answer 79

Hard deposit of insoluble minerals that collects inside the cooling system, reducing its ability to transfer heat. ## Footnote Scale acts as an insulator, significantly impacting heat transfer efficiency.

Question 80

How does a 1/16" mineral deposit affect heat transferability in cast iron?

Answer 80

A 1" cast iron plus a 1/16" mineral deposit is equivalent to 4" cast iron in heat transferability. ## Footnote This illustrates the significant impact of mineral deposits on heat transfer.

Question 81

What causes corrosion in a cooling system?

Answer 81

Corrosion occurs when metal combines with oxygen to form rust. ## Footnote Regular checks of the coolant's pH value are necessary to determine its acidity or alkalinity.

Question 82

What is cavitation in cooling systems?

Answer 82

Cavitation is the erosion of a material due to the repeated collapse of vapor pockets developed by liner expansion and vibration. ## Footnote This mechanical issue can lead to significant damage if not addressed.

Question 83

What solutions can address cavitation in a cooling system?

Answer 83

Solutions include pressurizing the cooling system, using inhibitor packages, and plating the liners. ## Footnote These methods help mitigate the effects of cavitation.

Question 84

What are common causes of overheating in a cooling system?

Answer 84

Common causes include low coolant level, scale build-up, improper functioning of the thermostat, cracked heads, and lack of circulation due to water pump failure. ## Footnote Identifying these issues is critical for maintaining engine performance.

Question 85

Fill in the blank: The coolant should be checked for its correct _______ value to determine whether it is acidic or alkaline.

Answer 85

pH ## Footnote Maintaining the correct pH level is crucial for preventing corrosion and ensuring system efficiency.

Question 86

What can cause aeration of the coolant?

Answer 86

Water pump sucking air or cracked heads

Question 87

Why is air in the coolant problematic?

Answer 87

It does not transfer heat well and causes hot spots in the engine

Question 88

What are obvious coolant leaks?

Answer 88

Leaks from pipes or water pumps on the outside of the engine

Question 89

What does a weep hole in the water pump indicate?

Answer 89

A leaking pump seal

Question 90

What can result from coolant entering a cylinder?

Answer 90

Hydraulic lock, leading to catastrophic damage

Question 91

What is a potential consequence of mixing coolant with engine oil?

Answer 91

Damage to bearings and other components

Question 92

What should be replaced with the correct sized plugs during coolant flushing?

Answer 92

Core plugs (frost plugs)

Question 93

What is the first step in troubleshooting a cooling system?

Answer 93

Ensure all sensors and temperature gauges are functioning correctly

Question 94

What should you check for in the cooling system before removing the radiator cap?

Answer 94

Coolant level in the expansion tank and radiator ## Footnote This indicates if the system is still under pressure.

Question 95

What should you check if the coolant level is low?

Answer 95

The oil for possible glycol contamination

Question 96

What should you do if the radiator core is dirty?

Answer 96

Blow or wash out the core in the opposite direction of air flow

Question 97

What should be tested or noted regarding the fan during inspection?

Answer 97

Proper operation of the fan

Question 98

What should be done with the radiator cap if it is faulty?

Answer 98

Test it or change it for a new one of the same pressure rating

Question 99

Fill in the blank: Mixing coolant with engine oil damages the _______.

Answer 99

bearings

Question 100

What instruments can be used to test the strength of antifreeze solution?

Answer 100

Hydrometer or refractometer ## Footnote These tools measure the concentration of antifreeze in the coolant.

Question 101

What should be done before inspecting the thermostat?

Answer 101

Drain the coolant below the level of the thermostat housing ## Footnote This prevents spillage and allows for safe removal of the thermostat.

Question 102

What is the purpose of submerging the thermostat into a container of water?

Answer 102

To monitor the temperature and check if the thermostat opens at the correct temperature ## Footnote The thermostat should open within 5°C (5°F to 10°F) of the rating stamped on it.

Question 103

What should be used when reinstalling the thermostat?

Answer 103

A new gasket ## Footnote This ensures a proper seal and prevents leaks.

Question 104

What is the acceptable temperature range for a thermostat to open based on its rating?

Answer 104

Within 5°C (5°F to 10°F) of the stamped rating ## Footnote This indicates that the thermostat is functioning properly.

Question 105

Fill in the blank: A thermostat should be installed with the sensor in the _______.

Answer 105

correct orientation ## Footnote Proper orientation is crucial for accurate temperature regulation.

Question 106

True or False: A refractometer can be used to test the condition of coolant.

Answer 106

True ## Footnote A refractometer measures the refractive index of the coolant to determine its concentration.

Question 107

What should be done before removing the water pump or engine components?

Answer 107

Drain the cooling system ## Footnote Draining is necessary to prevent coolant spillage and ensure safe handling.

Question 108

What must be replaced when installing a new water pump?

Answer 108

The pump with a new gasket ## Footnote A new gasket ensures a proper seal and prevents leaks.

Question 109

What should be checked after installing a new water pump?

Answer 109

The pump shaft for free rotation ## Footnote This ensures that the pump is functioning correctly without obstructions.

Question 110

What action should be taken if the drive belt looks worn?

Answer 110

Replace with a new one ## Footnote A worn drive belt can lead to pump failure and overheating.

Question 111

What is the purpose of flushing the cooling system?

Answer 111

To loosen scale build up in the radiator ## Footnote Flushing improves the efficiency of the cooling system.

Question 112

What should be done after draining the flushing solution?

Answer 112

Flush with clean water and drain again ## Footnote This step ensures that all contaminants are removed.

Question 113

What should be checked regarding the plugs in the cooling system?

Answer 113

Ensure all plugs are tight ## Footnote Loose plugs can lead to coolant leaks and system failure.

Question 114

What is the recommended coolant mixture for filling the radiator?

Answer 114

A 50/50 solution of glycol/water mix ## Footnote This mixture provides optimal freeze and boil protection.

Question 115

To what level should the radiator be filled?

Answer 115

Near the top, leaving room for coolant expansion ## Footnote This prevents overflow and allows for air bubble escape.

Question 116

What should be done after filling the radiator?

Answer 116

Run the engine to operating temperature ## Footnote Running the engine helps to circulate the coolant and expel trapped air.

Question 117

What should be done with the cooling system vent valve?

Answer 117

Open slowly until all air is removed ## Footnote This process ensures that the cooling system is fully primed.

Question 118

What should be done after removing air from the cooling system?

Answer 118

Fill the radiator and reinstall the radiator cap ## Footnote This completes the refilling process and seals the system.

Question 119

What is often referred to as the lifeblood of the engine?

Answer 119

Engine oil ## Footnote Engine oil is crucial for the proper functioning and longevity of the engine.

Question 120

What are the six primary functions of lubrication systems?

Answer 120

* Reduces friction between moving parts * Cools by absorbing and dissipating heat * Seals piston rings to cylinder walls * Cleans and flushes dirt and wear particles * Absorbs thrust and shock loads * Deadens noise ## Footnote These functions are vital for maintaining engine performance and reliability.

Question 121

Fill in the blank: The lubricant _______ friction between moving parts by separating the parts with an oil film.

Answer 121

reduces ## Footnote Reducing friction is essential for minimizing wear and tear on engine components.

Question 122

What does the lubricant do to help with cooling?

Answer 122

Absorbs and dissipates heat from internal parts ## Footnote Effective cooling prevents overheating and maintains optimal engine temperatures.

Question 123

What system uses dippers or slingers to supply oil?

Answer 123

Splash System ## Footnote The splash system is typically found in very small engines.

Question 124

Describe the splash and pressure lubrication system.

Answer 124

Most lubrication is done by the oil pump, with some points lubricated by splashing ## Footnote This system is commonly used in more complex engine designs.

Question 125

True or False: Full pressure lubrication systems only use splash methods for lubrication.

Answer 125

False ## Footnote Full pressure systems rely primarily on an oil pump for lubrication.

Question 126

What is the role of oil in sealing piston rings?

Answer 126

Leaves a very thin layer of oil in the crosshatch marks from honing ## Footnote This sealing helps maintain compression and engine efficiency.

Question 127

Fill in the blank: Lubrication systems must supply ample clean oil to every internal moving part in the engine through a broad range of _______.

Answer 127

operating temperatures and conditions ## Footnote This adaptability is crucial for engine performance under various conditions.

Question 128

What additional benefit does lubrication provide besides reducing friction?

Answer 128

Cleans and flushes dirt and wear particles ## Footnote Keeping the engine clean prolongs its life and efficiency.

Question 129

What is the primary function of a full-pressure lubrication system?

Answer 129

To supply oil under pressure to all points of lubrication by lines or oil galleries. ## Footnote This system ensures that oil reaches almost every component of the engine.

Question 130

List the six key components of a lubrication system.

Answer 130

* Oil sump or oil pan * Pickup screen * Oil pump * Filtering system * Oil coolers * Pressure relief valve ## Footnote These components work together to ensure effective lubrication within the engine.

Question 131

What is the purpose of the oil sump or oil pan in an engine?

Answer 131

To hold the oil and provide a reservoir for lubrication ## Footnote Smaller engines typically have oil pans, while larger engines may use the engine bed as a reservoir.

Question 132

True or False: The oil pan serves the same function in both smaller and larger engines.

Answer 132

False ## Footnote Smaller engines have oil pans, while larger engines use the engine bed as a reservoir.

Question 133

Fill in the blank: The __________ is responsible for drawing oil from the sump to the lubrication system.

Answer 133

[oil pump] ## Footnote The oil pump is a critical component that ensures oil is circulated throughout the engine.

Question 134

What role does the filtering system play in a lubrication system?

Answer 134

To remove contaminants from the oil ## Footnote A clean oil supply is essential for optimal engine performance.

Question 135

Explain the function of the pressure relief valve in a lubrication system.

Answer 135

To regulate oil pressure within the system ## Footnote This prevents damage to engine components by ensuring oil pressure does not exceed safe levels.

Question 136

What is the significance of having a larger oil supply in stationary engines?

Answer 136

It helps in cooling and allows the oil level to run lower without danger to the engine. ## Footnote This is particularly important for maintaining engine performance and longevity.

Question 137

What is the flow path of oil in a full-pressure lubrication system?

Answer 137

Oil flows from the oil pump through the main oil gallery to various components such as the oil filter and valve stem. ## Footnote This ensures that oil is delivered efficiently to all necessary parts of the engine.

Question 138

What is a pickup screen?

Answer 138

A coarse screen that fits to the oil pump inlet to filter large items ## Footnote It should not restrict the flow of oil.

Question 139

What type of pumps are used in the engine's main lubrication system?

Answer 139

Positive displacement rotary pumps ## Footnote Common types include external gear, vane, internal gear, and gerotor pumps.

Question 140

What is the primary purpose of the oil pump?

Answer 140

To supply an adequate flow of oil to all engine components.

Question 141

How is system pressure in the lubrication system determined?

Answer 141

By the bearing clearances (restriction to flow).

Question 142

What regulates the maximum pressure in the lubrication system?

Answer 142

The relief valve.

Question 143

What is the function of the filtering system in the lubrication system?

Answer 143

To remove particles that could damage engine bearings.

Question 144

What additional feature may be included in the oil reservoir to protect against metallic particles?

Answer 144

Magnetic retention plugs.

Question 145

Why are oil coolers important in industrial engines?

Answer 145

To ensure that the oil is cool enough to reduce oxidation, retain viscosity, and remove heat.

Question 146

What does the pressure relief valve do?

Answer 146

Safeguards engine components from excessive lube pressure.

Question 147

What can happen if the lube pressure is too high?

Answer 147

Erosion of bearings and burst filters.

Question 148

How is the maximum pressure of the pressure relief valve adjusted?

Answer 148

By adding or subtracting shims or turning an adjusting screw.

Question 149

What is the maximum system pressure range on industrial engines?

Answer 149

30 to 60 psi.

Question 150

Fill in the blank: The proper _________ _________ of spark plugs is important for cooling of the spark plugs

Answer 150

tightening torque.

Question 151

What is the primary filtration method used in most modern engines?

Answer 151

Full-flow filtration ## Footnote Full-flow filtration is the dominant system that ensures all oil is filtered after the oil pump.

Question 152

What occurs during full-flow filtration?

Answer 152

All oil is filtered after the oil pump and before reaching the bearings ## Footnote This is essential for maintaining engine health by ensuring clean oil reaches critical components.

Question 153

What is the function of the bypass valve in full-flow filtration?

Answer 153

Allows oil to reach the bearings during cold start-ups or when the filter is plugged ## Footnote This valve ensures that the engine receives lubrication even under adverse conditions.

Question 154

In a bypass lube system, what percentage of oil is typically filtered?

Answer 154

5% to 10% ## Footnote This amount is passed through the filter and returned to the sump, characteristic of older engine designs.

Question 155

Describe the oil flow in a bypass filtration system.

Answer 155

Oil is pumped from the sump directly to the bearings, with a filter system running in parallel ## Footnote This design allows for less effective oil filtration compared to full-flow systems.

Question 156

What is the main function of the oil pump in both filtration systems?

Answer 156

To circulate oil through the engine components ## Footnote The oil pump is crucial for maintaining lubrication and cooling.

Question 157

True or False: Full-flow filtration systems do not include a bypass valve.

Answer 157

False ## Footnote Full-flow systems include a bypass valve to manage oil flow under specific conditions.

Question 158

Fill in the blank: In a bypass lube system, the filter is _______ _______ with the lube system.

Answer 158

in parallel ## Footnote This configuration distinguishes it from full-flow systems.

Question 159

What role does the pressure regulating valve play in oil filtration systems?

Answer 159

Maintains optimal oil pressure ## Footnote This valve ensures that oil pressure remains within safe limits for engine operation.

Question 160

List two types of oil filtration systems mentioned.

Answer 160

* Full-flow filtration * Bypass filtration ## Footnote These systems represent different approaches to engine oil management.

Question 161

What is the primary function of filters in both full flow and bypass systems?

Answer 161

To remove particles from oil

Question 162

What do surface filters use to filter oil?

Answer 162

Pleated screens or paper ## Footnote Surface filters have a micron rating that determines the size of particles that can pass through.

Question 163

How do surface filters operate?

Answer 163

They allow only certain sized particles to flow through while larger particles collect on the surface

Question 164

What materials are used in depth filters?

Answer 164

Cotton, wood chips, or steel wool

Question 165

How do depth filters capture particles?

Answer 165

By forcing oil through fibrous material that traps small particles below the surface

Question 166

Fill in the blank: Surface filters have a _______ rating that allows particles of only a certain size to flow through.

Answer 166

micron

Question 167

True or False: Depth filters collect larger particles on the surface.

Answer 167

False

Question 168

What is the main difference between surface filters and depth filters?

Answer 168

Surface filters trap larger particles on the surface, while depth filters trap particles within the filter material

Question 169

What are edge filters composed of?

Answer 169

A stack of discs that alternate from a filter disc to a spacer disc ## Footnote Edge filters also include cleaning blades that contact the filter disc.

Question 170

How do edge filters clean themselves?

Answer 170

By turning the handle on the outside of the canister, which cause the cleaning blades knock off trapped particles ## Footnote The particles fall to the bottom sump of the canister.

Question 171

What principle do centrifuge filters operate on?

Answer 171

The different density of particles in the oil ## Footnote Water and solid particles are heavier than oil, causing separation when spun.

Question 172

What is the function of pre-lube pump system in industrial engines?

Answer 172

To get oil to critical parts of the engine before start-up ## Footnote This helps lubricate components during the highest wear period.

Question 173

What is the purpose of pre-lube systems?

Answer 173

To lubricate the engine and turbocharger bearings before the engine is turned over ## Footnote This reduces wear during start-up.

Question 174

Fill in the blank: Edge filters use _______ _______ to remove particles trapped between discs.

Answer 174

cleaning blades

Question 175

True or False: Centrifuge filters separate heavy particles from oil by spinning.

Answer 175

True

Question 176

What happens to heavy particles and water in centrifuge filters?

Answer 176

They separate from the oil due to their higher density ## Footnote This process enhances the purity of the oil.

Question 177

What is a key benefit of using a pre-lube pump system?

Answer 177

It minimizes wear during engine start-up ## Footnote Start-up is when the highest rate of wear occurs.

Question 178

What is the function of oil coolers in an engine?

Answer 178

To transfer heat from the oil to the engine coolant ## Footnote Oil coolers are essential in maintaining optimal engine temperatures.

Question 179

What component is commonly found in heat exchangers to control oil circulation?

Answer 179

Thermostatically operated bypass valve ## Footnote This valve prevents oil from circulating until the temperature reaches a pre-set value.

Question 180

Why are oil heaters used in engines?

Answer 180

To heat the oil before engine startup in cold weather ## Footnote They are also used for engines on standby to allow quick startup.

Question 181

What is the benefit of maintaining oil and coolant at a predetermined temperature?

Answer 181

Allows the engine to be put online at full speed and power quickly ## Footnote This is crucial for standby engine generator units in facilities like hospitals.

Question 182

What is critical when selecting engine oil?

Answer 182

It must be matched to the application and operating conditions ## Footnote Different oils are recommended for naturally aspirated engines versus turbocharged engines.

Question 183

What should always be referred to when selecting engine oil?

Answer 183

The manufacturer's recommendations ## Footnote This ensures the oil is suitable for particular operating conditions.

Question 184

What regular maintenance is essential for the lubrication system?

Answer 184

Perform regular servicing ## Footnote This is necessary to assure maximum performance of the lubrication system.

Question 185

What five factors affect oil and filter change intervals in industrial engines?

Answer 185

Factors include: * Type of fuel burned * Quality of fuel * Environmental conditions * Amount of oil in the sump * Extent of filtration systems ## Footnote Different fuels and environmental conditions can lead to varying levels of oil contamination.

Question 186

How does the type of fuel affect oil contamination in engines?

Answer 186

Engines burning gaseous fuels like natural gas and propane sustain much less oil contamination than those using liquid fuels. ## Footnote The presence of HeS in gas requires more frequent oil changes.

Question 187

What environmental conditions necessitate more frequent oil changes?

Answer 187

Conditions such as heat, dust, or other adversities require more frequent oil changes. ## Footnote Adverse environments can accelerate oil degradation.

Question 188

How does the capacity of the oil sump influence oil change intervals?

Answer 188

Large capacity sumps can be changed less often. ## Footnote Larger sumps can hold more oil, which can extend the time between changes.

Question 189

What is the role of centrifuge oil filters in oil change intervals?

Answer 189

Centrifuge oil filters help maintain oil quality, often allowing for longer intervals between oil changes. ## Footnote These filters can remove contaminants effectively.

Question 190

What is the benefit of using synthetic oils in engines?

Answer 190

Synthetic oils often allow for longer oil change intervals due to their enhanced properties. ## Footnote Synthetic oils have better thermal stability and resistance to oxidation.

Question 191

What is the purpose of oil analysis in predictive maintenance?

Answer 191

Oil analysis determines the condition of the oil and wear in the engine, indicating when oil requires replacement. ## Footnote Regular sampling helps in planning maintenance effectively.

Question 192

When should an oil sample be taken for analysis?

Answer 192

An oil sample should be taken just prior to an engine shut down. ## Footnote This prevents sediment from settling out before the sample is collected.

Question 193

True or False: Oil filters may need to be changed in the middle of the recommended oil change interval.

Answer 193

True ## Footnote This is advisable when a comprehensive oil analysis program is in place.

Question 194

Fill in the blank: Lube oil analysis determines the condition of the oil and ______ in the engine.

Answer 194

wear ## Footnote Regularly scheduled sampling is crucial for effective maintenance.

Question 195

What is the first step in changing engine oil and filter?

Answer 195

Lock out the fuel, ignition and starting systems.

Question 196

Why should oil be drained while the engine is warm?

Answer 196

Warm oil drains more easily.

Question 197

What should be inspected after removing an engine oil filter?

Answer 197

The filter element for metal particles.

Question 198

What should be done to the seal surface of an engine filter base?

Answer 198

Clean the seal surface.

Question 199

When changing an engine oil fitler, what should be done to the new oil filter gasket before installation?

Answer 199

Lubricate it with clean engine oil.

Question 200

When changing an engine filter, fill the new filter element with oil before installation: True or False?

Answer 200

False.

Question 201

When replacing an engine oil filter, how much should the new oil filter be turned after the gasket makes contact?

Answer 201

½ to ¾ turn.

Question 202

What should be done after filling the crankcase with oil?

Answer 202

Run the pre lube pump briefly to lubricate engine bearings.

Question 203

What is the purpose of cranking the engine with the fuel valve off after an oil change?

Answer 203

To fill the oil filters and piping before running the engine.

Question 204

Afrer replacing the engine oil, what should be checked after running the engine at idle?

Answer 204

Oil pressure gauge and inspect for leaks.

Question 205

What should be done after stopping the engine post oil change?

Answer 205

Let the oil drain back to the oil sump for a few minutes and recheck the oil level.

Question 206

What is a normal reason for oil consumption in engines?

Answer 206

Oil lubricating the piston rings and cylinder.

Question 207

What is the primary concern regarding oil consumption?

Answer 207

That it is not excessive: The amount of oil consumed for the size of the engine.

Question 208

How does engine size affect oil consumption?

Answer 208

Larger engines have more surface area, leading to more oil loss.

Question 209

What factors affect oil pressure?

Answer 209

Viscosity of the oil, amount of bearing clearance, and volume of the oil pump.

Question 210

What should be done first if there is no oil pressure?

Answer 210

Shut down the engine.

Question 211

What is one of the most common problems with lubrication systems?

Answer 211

Low oil pressure ## Footnote Common issue that can lead to engine damage if not addressed.

Question 212

What should be installed on the engine before performing repairs for low oil pressure?

Answer 212

A master oil gauge ## Footnote It helps to determine if the instrument gauge is faulty.

Question 213

List six main causes of low oil pressure.

Answer 213

* Not enough oil in the crankcase * Higher than normal bearing clearances * Oil viscosity that is too low due to high-temperature operation * Worn oil pump * Plugged inlet strainer * Oil pump relief valve being stuck open or having a broken spring ## Footnote Other causes include worn oil pump, plugged pump strainer, and a stuck open oil pump relief valve.

Question 214

What can change the viscosity of the oil?

Answer 214

Fuel or water dilution ## Footnote This can lead to low oil pressure issues.

Question 215

Is high oil pressure a common problem?

Answer 215

No ## Footnote High oil pressure is less common than low oil pressure.

Question 216

What are three causes of high oil pressure?

Answer 216

* High oil viscosity * Relief valve set too high * Blockages ## Footnote These issues can lead to excessive pressure in the system.

Question 217

When is it normal to expect higher oil pressure?

Answer 217

When the engine is cold ## Footnote However, it should not be excessive.

Question 218

What can excessive oil pressure lead to?

Answer 218

* Ruptured oil filters * Washed out bearings ## Footnote These issues can occur if excessive pressure continues for extended periods.

Question 219

What does an oil pressure test indicate?

Answer 219

The condition of the oil pump ## Footnote It provides a partial indication of pump health.

Question 220

What components should be visually inspected on the oil pump?

Answer 220

* Pump housing * Cover * Gears * Shafts * Pressure relief valve assembly ## Footnote Inspection compares wear to limits established by the engine manufacturer.

Question 221

What are some signs of wear to check during oil pump inspection?

Answer 221

* Score marks * Worn shaft * Cracked housing * Teeth pits * Checking end play ## Footnote These signs indicate potential issues with the oil pump components.

Question 222

What is the primary function of the crankcase ventilation system?

Answer 222

To remove combustion gases and water vapours from the crankcase ## Footnote This is essential to prevent issues such as oil foaming and sludge formation.

Question 223

What is blow-by in the context of crankcase ventilation?

Answer 223

The escape of combustion gases past the piston rings into the crankcase ## Footnote This occurs during normal engine operation.

Question 224

What can excessive crankcase pressure lead to?

Answer 224

Engine oil seal leaks ## Footnote This is especially a concern in turbocharged engines.

Question 225

What is a potential consequence of oil and water mixing in the crankcase?

Answer 225

Formation of sludge ## Footnote This emulsion can lead to oil foaming if not removed.

Question 226

What does a passive crankcase ventilation system typically include?

Answer 226

A breather with a mesh filter and a vent tube ## Footnote This allows air into the engine and crankcase air to escape to the atmosphere.

Question 227

True or False: A passive ventilation system prevents crankcase emissions from entering the atmosphere.

Answer 227

False ## Footnote Crankcase emissions are sent directly to the atmosphere.

Question 228

What type of vapour can enter the crankcase from exhaust gases?

Answer 228

Water vapour ## Footnote This can contribute to the mixing with oil.

Question 229

Fill in the blank: The crankcase ventilation system must remove combustion gases and _______ _______ to prevent problems.

Answer 229

water vapours ## Footnote Removing these prevents sludge formation and oil foaming.

Question 230

What is a potential risk if sulphuric acid forms in the oil?

Answer 230

Increased engine wear and damage ## Footnote This is a risk associated with excessive crankcase pressure.

Question 231

What is the primary function of a positive crankcase ventilation (PCV) system?

Answer 231

To ventilate the crankcase and prevent buildup of harmful gases ## Footnote The PCV system helps in controlling the internal pressure of the crankcase.

Question 232

In a positive crankcase ventilation system, what type of pressure can be present in the crankcase?

Answer 232

Positive pressure or vacuum ## Footnote Automotive engines typically exhibit positive pressure.

Question 233

What component prevents the reversal of exhausted air back into the crankcase in a PCV system?

Answer 233

PCV valve ## Footnote The PCV valve is a one-way check valve installed in the ventilation line.

Question 234

Where is the PCV line connected in turbocharged engines?

Answer 234

Before the turbo ## Footnote This connection helps manage pressure in the intake manifold.

Question 235

What is the purpose of a filter or separator in turbocharged engines' PCV systems?

Answer 235

To remove oil and vapor carryover ## Footnote This prevents contamination of the turbocharger.

Question 236

What type of pressure does a negative pressure positive crankcase system create in the crankcase?

Answer 236

0 to 0.5 inches of water column ## Footnote This vacuum helps prevent lube oil leaks and crankcase explosions.

Question 237

How can the amount of vacuum in the crankcase be adjusted?

Answer 237

By changing the orifice size in the breather line ## Footnote Adjusting the orifice controls the airflow into the crankcase.

Question 238

What are the potential issues with a crankcase that has positive suction?

Answer 238

Over-scavenging and oil consumption ## Footnote Over-scavenging occurs when excessive air is pulled through the system along with oil vapors.

Question 239

What component can be used to limit the amount of air passing through a crankcase ventilation system?

Answer 239

Orifice ## Footnote An orifice can help regulate air flow and prevent oil loss.

Question 240

What tool can be used to check the correct value of the crankcase ventilation system?

Answer 240

Manometer ## Footnote A manometer can also indicate issues like excessive blowby.

Question 241

True or False: The absence of a breather filter in the crankcase ventilation system can lead to engine oil contamination.

Answer 241

True ## Footnote Dirty air entering without a breather can contaminate the engine oil.

Question 242

Fill in the blank: The breather assembly filled with a _______ eliminates the pull-over of oil.

Answer 242

wire mesh ## Footnote A wire mesh helps to prevent oil vapors from being pulled into the air system.

Question 243

What potential engine problems can a crankcase manometer help detect?

Answer 243

Leaking rings or scuffed liners ## Footnote It provides early indications of engine issues related to crankcase pressure.

Question 244

Due to emission standards, where should crankcase gases be directed on a passive system?

Answer 244

To atmosphere

Question 245

Due to emission standards, where should crankcase gases be directed on a pressurized system?

Answer 245

To the inlet manifold, inlet of the turbocharger, or the a venturi in the exhaust system

Question 246

True or false: Multi-grade oils are recommended for natural gas engines that operate in normal environments.

Answer 246

False

Question 247

What are pre- and post-lube pumps driven by?

Answer 247

Pneumatic or electric motor

Question 248

Which of the engine thermostats listed is the most common and is not sensitive to pressure?

Answer 248

Wax pellet type

Question 249

How are engines with large crossheads lubricated?

Answer 249

With oil injected directly into the cylinders.

Question 250

What causes the air to flow through a carburetor?

Answer 250

The movement of the piston. | This creates the vacuumm to open the air valve.

Question 251

What is the main issue that will arise from engine crankshaft deflection?

Answer 251

Crankshaft fatigue

Question 252

True or false: Diesel fuel is not an answer for any question about which fuel would detonate.

Answer 252

True. | Looking for the classical detonation in a spark engine. ## Footnote While diesel is designed to detonate, these questions are asking about which fuel has either the highest or lowest octane rating.