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Millwrong > Engines - Exhaust, Cooling, Lubrication and Ventilation > Flashcards

Engines - Exhaust, Cooling, Lubrication and Ventilation Flashcards

1
Q

What are the main components of an exhaust system?

A

Exhaust manifold, piping, silencer

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

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2
Q

What is the primary function of an exhaust system?

A

To collect and remove exhaust with minimum restriction and adequate silencing

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

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3
Q

What role does the muffler play in the exhaust system?

A

Reduces noise from pulsations in the exhaust system

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

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4
Q

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

A

False

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

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5
Q

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

A

Rain cap

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

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6
Q

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

A

Allow for thermal expansion and reduce vibration transfer

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

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7
Q

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

A

manifold

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

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8
Q

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

A

To ensure efficient engine operation

Minimum backpressure helps maintain optimal exhaust flow and engine performance.

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9
Q

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

A
  • Rain cap
  • Exhaust pipe cut on an angle

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

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10
Q

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

A

Discharges into the atmosphere

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

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11
Q

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

A

To reduce harmful emissions before they exit into the atmosphere

Catalytic converters play a critical role in meeting environmental regulations.

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12
Q

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

A

A thorough inspection and diagnosis of the entire system

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

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13
Q

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

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

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

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14
Q

What effect does backpressure have on an engine?

A

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.

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15
Q

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

A

A mercury manometer

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

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16
Q

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

A

1 psi or less

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

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17
Q

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

A

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.

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18
Q

What happens to exhaust manifolds during heating and cooling cycles?

A

They go through stress and corrosion

This can affect their integrity and sealing capability.

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19
Q

What is a common issue when removing an exhaust manifold?

A

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.

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20
Q

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

A

1 psi or less

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21
Q

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

A

False

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

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22
Q

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

A

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

While not good, water is better than mercury

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23
Q

What is the main function of the engine cooling system?

A

To regulate engine temperature

This ensures optimal engine efficiency and longevity.

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24
Q

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

A
  • Conduction
  • Convection
  • Radiation

These methods help maintain appropriate engine temperatures.

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25
Q

Define conduction in the context of an engine cooling system.

A

The transfer of heat from molecule to molecule, occurring when heat from the block, heads, and liners transfers to the coolant.

This process is essential for heat management in the engine.

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26
Q

What is convection in the cooling system?

A

The transfer of heat by movement of a medium such as coolant and air.

It involves circulating coolant with the water pump and/or moving air through the heat exchanger.

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27
Q

Explain radiation in the context of heat transfer.

A

The transfer of heat through space by electromagnetic waves from one object to another.

The sun is an example of radiant heat transfer.

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28
Q

What is the optimal temperature range for most engines?

A

82°C to 95°C (180°F to 200°F)

Maintaining this range is crucial for engine performance.

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29
Q

What six problems can arise from engine overheating?

A
  • Pre-ignition
  • Detonation
  • Burnt pistons
  • Burnt valves
  • Scored liners
  • Lube oil breakdown

These issues can lead to severe engine damage.

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30
Q

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

A
  • Sludge accumulation
  • Water accumulation in the crankcase
  • Poor fuel economy
  • Unnecessary engine wear

These issues can degrade engine performance and longevity.

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31
Q

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

A

overheating, overcooling

Both conditions can lead to engine failure.

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32
Q

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

A

True

This can negatively affect engine performance.

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33
Q

What can happen if a thermostat fails or is missing?

A

The engine will run too cool

This can lead to various engine issues.

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34
Q

True or false:

Water is a byproduct of-product of combustion.

A

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

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35
Q

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

A

Fins on cylinders and heads, forced-air fan, shrouding, and baffles

The fins increase surface area to facilitate heat removal.

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36
Q

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

A

By directing airflow to hot points using shrouding and baffles

Temperature regulation can also involve a thermostatic valve.

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37
Q

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

A

In an open system, coolant is not recirculated and is sourced from external water supplies

This includes city water utilities, reservoirs, or lakes.

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38
Q

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

A

To reject heat from the recirculated coolant

This allows for conditioning of the coolant to minimize scale buildup.

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39
Q

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

A

Creates coolant flow

It is essential for maintaining circulation within the system.

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40
Q

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

A

Thermostat

The thermostat ensures optimal temperature control.

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41
Q

List the main parts of a cooling system.

A
  • 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

These components work together to manage engine temperature.

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42
Q

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

A

True

This system allows for efficient heat dissipation and coolant reuse.

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43
Q

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

A

recirculated

This process helps prolong the life of the cooling system.

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44
Q

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

A
  • Chromates
  • Nitrates

These additives help protect engine components from wear.

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45
Q

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

A

To create a continuous flow in the cooling system, even when the thermostat is closed.

This helps to circulate coolant to the hottest part of the engine.

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46
Q

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

A

Centrifugal, non-positive, displacement-type pump.

These pumps are driven by the engine.

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47
Q

How can water pumps be driven in an engine?

A

By belts, chains, or gears.

These drive mechanisms are essential for the operation of the water pump.

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48
Q

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

A

To sense engine temperature and maintain operating limits by controlling coolant flow.

It helps to direct coolant either to the radiator or back to the water pump.

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49
Q

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

A

Wax pellet type.

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

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50
Q

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

A

To reduce warm-up time and prevent the cylinder head from overheating when the thermostat is closed.

It allows coolant to recirculate back to the engine.

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51
Q

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

A

True.

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

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52
Q

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

A

toward the engine.

Proper installation is crucial for the thermostat to function correctly.

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53
Q

What happens to larger engines regarding thermostat design?

A

They may have more than one thermostat to allow for a large volume of coolant flow.

Some large engines with individual cylinder heads may have a thermostat on each head.

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54
Q

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

A

It ensures that the top part of the engine, which may be the hottest, remains cooled.

This is critical for engine performance and longevity.

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55
Q

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

A

Radiator or heat exchanger

The radiator also acts as a reservoir for the coolant in a closed loop system.

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56
Q

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

A

Regulates system pressure above atmospheric pressure

Allows pressure to build in the system.

This increase in pressure raises the boiling point temperature of the coolant.

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57
Q

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

A

True

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

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58
Q

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

A

Fills coolant, allows expansion, and de-aerates coolant

It must be above the engine and has vent lines to eliminate air or steam pockets.

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59
Q

Where must an expansion tank be located on an engine?

A

Above it

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

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60
Q

What drives the fan in small engines?

A

Belt-driven fan attached to the water pump

Similar to the design on mobile equipment.

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61
Q

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

A

Long belt-driven fan shaft attached to the front of the engine

The fan is outside the building, and no air from the fan moves past the engine.

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62
Q

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

A

Electric fans

These fans are activated by temperature switches.

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63
Q

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

A

Keeps the cooling system clean and extends the life of water pump seals and liner O-rings

Effective in maintaining the system’s cleanliness.

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64
Q

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

A

3

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

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65
Q

What is the typical micron size for coolant filters?

A

15 - 25 microns

This specification helps maintain the cleanliness of the cooling system.

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66
Q

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

A

The radiator cap

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67
Q

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

A

More durable

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

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68
Q

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

A

Approximately 15%

Water’s heat absorption capacity makes it an effective coolant.

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69
Q

What are the boiling and freezing temperatures of water?

A

100°C (212°F) and 0°C (32°F)

These temperatures are critical in determining the effectiveness of water as a coolant.

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70
Q

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

A

It expands, potentially cracking the engine block and cylinder heads

Expansion can also damage the radiator and heater core.

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71
Q

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

A

Ethylene glycol and propylene glycol

These compounds are commonly used due to their effective thermal properties.

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72
Q

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

A

50/50 solution of distilled water and antifreeze

This mixture balances the boiling and freezing points for better performance.

Left = boiling point, right = freezing point

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73
Q

What is a key disadvantage of ethylene glycol based coolant?

A

It is toxic and hazardous to the environment

Despite its high boiling point, its toxicity is a significant concern.

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74
Q

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

A

It is non-toxic and less hazardous to the environment

This makes it a safer option for various applications.

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75
Q

What is a disadvantage of propylene glycol based coolant?

A

Lower boiling point than ethylene glycol and can react with some materials

This limits its effectiveness in certain situations.

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76
Q

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

A

Boils at 375°F, no corrosion

Waterless coolant is gaining popularity due to its ability to prevent corrosion and operate at higher temperatures.

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77
Q

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

A

liquid

Maintaining a liquid state is crucial for effective cooling.

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78
Q

What happens when glycol is introduced into the lubrication system?

A

The oil/glycol mixture becomes acidic, damaging engine bearings, increasing oil viscosity, and corroding engine component surfaces.

Glycol can lead to significant mechanical failures if not managed properly.

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79
Q

What is scale in the context of cooling systems?

A

Hard deposit of insoluble minerals that collects inside the cooling system, reducing its ability to transfer heat.

Scale acts as an insulator, significantly impacting heat transfer efficiency.

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80
Q

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

A

A 1” cast iron plus a 1/16” mineral deposit is equivalent to 4” cast iron in heat transferability.

This illustrates the significant impact of mineral deposits on heat transfer.

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81
Q

What causes corrosion in a cooling system?

A

Corrosion occurs when metal combines with oxygen to form rust.

Regular checks of the coolant’s pH value are necessary to determine its acidity or alkalinity.

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82
Q

What is cavitation in cooling systems?

A

Cavitation is the erosion of a material due to the repeated collapse of vapor pockets developed by liner expansion and vibration.

This mechanical issue can lead to significant damage if not addressed.

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83
Q

What solutions can address cavitation in a cooling system?

A

Solutions include pressurizing the cooling system, using inhibitor packages, and plating the liners.

These methods help mitigate the effects of cavitation.

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84
Q

What are common causes of overheating in a cooling system?

A

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.

Identifying these issues is critical for maintaining engine performance.

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85
Q

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

A

pH

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

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86
Q

What can cause aeration of the coolant?

A

Water pump sucking air or cracked heads

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87
Q

Why is air in the coolant problematic?

A

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

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88
Q

What are obvious coolant leaks?

A

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

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89
Q

What does a weep hole in the water pump indicate?

A

A leaking pump seal

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90
Q

What can result from coolant entering a cylinder?

A

Hydraulic lock, leading to catastrophic damage

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91
Q

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

A

Damage to bearings and other components

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92
Q

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

A

Core plugs (frost plugs)

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93
Q

What is the first step in troubleshooting a cooling system?

A

Ensure all sensors and temperature gauges are functioning correctly

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94
Q

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

A

Coolant level in the expansion tank and radiator

This indicates if the system is still under pressure.

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95
Q

What should you check if the coolant level is low?

A

The oil for possible glycol contamination

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96
Q

What should you do if the radiator core is dirty?

A

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

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97
Q

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

A

Proper operation of the fan

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98
Q

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

A

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

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99
Q

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

A

bearings

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100
Q

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

A

Hydrometer or refractometer

These tools measure the concentration of antifreeze in the coolant.

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101
Q

What should be done before inspecting the thermostat?

A

Drain the coolant below the level of the thermostat housing

This prevents spillage and allows for safe removal of the thermostat.

102
Q

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

A

To monitor the temperature and check if the thermostat opens at the correct temperature

The thermostat should open within 5°C (5°F to 10°F) of the rating stamped on it.

103
Q

What should be used when reinstalling the thermostat?

A

A new gasket

This ensures a proper seal and prevents leaks.

104
Q

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

A

Within 5°C (5°F to 10°F) of the stamped rating

This indicates that the thermostat is functioning properly.

105
Q

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

A

correct orientation

Proper orientation is crucial for accurate temperature regulation.

106
Q

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

A

True

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

107
Q

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

A

Drain the cooling system

Draining is necessary to prevent coolant spillage and ensure safe handling.

108
Q

What must be replaced when installing a new water pump?

A

The pump with a new gasket

A new gasket ensures a proper seal and prevents leaks.

109
Q

What should be checked after installing a new water pump?

A

The pump shaft for free rotation

This ensures that the pump is functioning correctly without obstructions.

110
Q

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

A

Replace with a new one

A worn drive belt can lead to pump failure and overheating.

111
Q

What is the purpose of flushing the cooling system?

A

To loosen scale build up in the radiator

Flushing improves the efficiency of the cooling system.

112
Q

What should be done after draining the flushing solution?

A

Flush with clean water and drain again

This step ensures that all contaminants are removed.

113
Q

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

A

Ensure all plugs are tight

Loose plugs can lead to coolant leaks and system failure.

114
Q

What is the recommended coolant mixture for filling the radiator?

A

A 50/50 solution of glycol/water mix

This mixture provides optimal freeze and boil protection.

115
Q

To what level should the radiator be filled?

A

Near the top, leaving room for coolant expansion

This prevents overflow and allows for air bubble escape.

116
Q

What should be done after filling the radiator?

A

Run the engine to operating temperature

Running the engine helps to circulate the coolant and expel trapped air.

117
Q

What should be done with the cooling system vent valve?

A

Open slowly until all air is removed

This process ensures that the cooling system is fully primed.

118
Q

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

A

Fill the radiator and reinstall the radiator cap

This completes the refilling process and seals the system.

119
Q

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

A

Engine oil

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

120
Q

What are the six primary functions of lubrication systems?

A
  • 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

These functions are vital for maintaining engine performance and reliability.

121
Q

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

A

reduces

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

122
Q

What does the lubricant do to help with cooling?

A

Absorbs and dissipates heat from internal parts

Effective cooling prevents overheating and maintains optimal engine temperatures.

123
Q

What system uses dippers or slingers to supply oil?

A

Splash System

The splash system is typically found in very small engines.

124
Q

Describe the splash and pressure lubrication system.

A

Most lubrication is done by the oil pump, with some points lubricated by splashing

This system is commonly used in more complex engine designs.

125
Q

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

A

False

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

126
Q

What is the role of oil in sealing piston rings?

A

Leaves a very thin layer of oil in the crosshatch marks from honing

This sealing helps maintain compression and engine efficiency.

127
Q

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

A

operating temperatures and conditions

This adaptability is crucial for engine performance under various conditions.

128
Q

What additional benefit does lubrication provide besides reducing friction?

A

Cleans and flushes dirt and wear particles

Keeping the engine clean prolongs its life and efficiency.

129
Q

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

A

To supply oil under pressure to all points of lubrication by lines or oil galleries.

This system ensures that oil reaches almost every component of the engine.

130
Q

List the six key components of a lubrication system.

A
  • Oil sump or oil pan
  • Pickup screen
  • Oil pump
  • Filtering system
  • Oil coolers
  • Pressure relief valve

These components work together to ensure effective lubrication within the engine.

131
Q

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

A

To hold the oil and provide a reservoir for lubrication

Smaller engines typically have oil pans, while larger engines may use the engine bed as a reservoir.

132
Q

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

A

False

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

133
Q

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

A

[oil pump]

The oil pump is a critical component that ensures oil is circulated throughout the engine.

134
Q

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

A

To remove contaminants from the oil

A clean oil supply is essential for optimal engine performance.

135
Q

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

A

To regulate oil pressure within the system

This prevents damage to engine components by ensuring oil pressure does not exceed safe levels.

136
Q

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

A

It helps in cooling and allows the oil level to run lower without danger to the engine.

This is particularly important for maintaining engine performance and longevity.

137
Q

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

A

Oil flows from the oil pump through the main oil gallery to various components such as the oil filter and valve stem.

This ensures that oil is delivered efficiently to all necessary parts of the engine.

138
Q

What is a pickup screen?

A

A coarse screen that fits to the oil pump inlet to filter large items

It should not restrict the flow of oil.

139
Q

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

A

Positive displacement rotary pumps

Common types include external gear, vane, internal gear, and gerotor pumps.

140
Q

What is the primary purpose of the oil pump?

A

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

141
Q

How is system pressure in the lubrication system determined?

A

By the bearing clearances (restriction to flow).

142
Q

What regulates the maximum pressure in the lubrication system?

A

The relief valve.

143
Q

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

A

To remove particles that could damage engine bearings.

144
Q

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

A

Magnetic retention plugs.

145
Q

Why are oil coolers important in industrial engines?

A

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

146
Q

What does the pressure relief valve do?

A

Safeguards engine components from excessive lube pressure.

147
Q

What can happen if the lube pressure is too high?

A

Erosion of bearings and burst filters.

148
Q

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

A

By adding or subtracting shims or turning an adjusting screw.

149
Q

What is the maximum system pressure range on industrial engines?

A

30 to 60 psi.

150
Q

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

A

tightening torque.

151
Q

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

A

Full-flow filtration

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

152
Q

What occurs during full-flow filtration?

A

All oil is filtered after the oil pump and before reaching the bearings

This is essential for maintaining engine health by ensuring clean oil reaches critical components.

153
Q

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

A

Allows oil to reach the bearings during cold start-ups or when the filter is plugged

This valve ensures that the engine receives lubrication even under adverse conditions.

154
Q

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

A

5% to 10%

This amount is passed through the filter and returned to the sump, characteristic of older engine designs.

155
Q

Describe the oil flow in a bypass filtration system.

A

Oil is pumped from the sump directly to the bearings, with a filter system running in parallel

This design allows for less effective oil filtration compared to full-flow systems.

156
Q

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

A

To circulate oil through the engine components

The oil pump is crucial for maintaining lubrication and cooling.

157
Q

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

A

False

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

158
Q

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

A

in parallel

This configuration distinguishes it from full-flow systems.

159
Q

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

A

Maintains optimal oil pressure

This valve ensures that oil pressure remains within safe limits for engine operation.

160
Q

List two types of oil filtration systems mentioned.

A
  • Full-flow filtration
  • Bypass filtration

These systems represent different approaches to engine oil management.

161
Q

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

A

To remove particles from oil

162
Q

What do surface filters use to filter oil?

A

Pleated screens or paper

Surface filters have a micron rating that determines the size of particles that can pass through.

163
Q

How do surface filters operate?

A

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

164
Q

What materials are used in depth filters?

A

Cotton, wood chips, or steel wool

165
Q

How do depth filters capture particles?

A

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

166
Q

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

A

micron

167
Q

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

A

False

168
Q

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

A

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

169
Q

What are edge filters composed of?

A

A stack of discs that alternate from a filter disc to a spacer disc

Edge filters also include cleaning blades that contact the filter disc.

170
Q

How do edge filters clean themselves?

A

By turning the handle on the outside of the canister, which cause the cleaning blades knock off trapped particles

The particles fall to the bottom sump of the canister.

171
Q

What principle do centrifuge filters operate on?

A

The different density of particles in the oil

Water and solid particles are heavier than oil, causing separation when spun.

172
Q

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

A

To get oil to critical parts of the engine before start-up

This helps lubricate components during the highest wear period.

173
Q

What is the purpose of pre-lube systems?

A

To lubricate the engine and turbocharger bearings before the engine is turned over

This reduces wear during start-up.

174
Q

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

A

cleaning blades

175
Q

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

A

True

176
Q

What happens to heavy particles and water in centrifuge filters?

A

They separate from the oil due to their higher density

This process enhances the purity of the oil.

177
Q

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

A

It minimizes wear during engine start-up

Start-up is when the highest rate of wear occurs.

178
Q

What is the function of oil coolers in an engine?

A

To transfer heat from the oil to the engine coolant

Oil coolers are essential in maintaining optimal engine temperatures.

179
Q

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

A

Thermostatically operated bypass valve

This valve prevents oil from circulating until the temperature reaches a pre-set value.

180
Q

Why are oil heaters used in engines?

A

To heat the oil before engine startup in cold weather

They are also used for engines on standby to allow quick startup.

181
Q

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

A

Allows the engine to be put online at full speed and power quickly

This is crucial for standby engine generator units in facilities like hospitals.

182
Q

What is critical when selecting engine oil?

A

It must be matched to the application and operating conditions

Different oils are recommended for naturally aspirated engines versus turbocharged engines.

183
Q

What should always be referred to when selecting engine oil?

A

The manufacturer’s recommendations

This ensures the oil is suitable for particular operating conditions.

184
Q

What regular maintenance is essential for the lubrication system?

A

Perform regular servicing

This is necessary to assure maximum performance of the lubrication system.

185
Q

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

A

Factors include:
* Type of fuel burned
* Quality of fuel
* Environmental conditions
* Amount of oil in the sump
* Extent of filtration systems

Different fuels and environmental conditions can lead to varying levels of oil contamination.

186
Q

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

A

Engines burning gaseous fuels like natural gas and propane sustain much less oil contamination than those using liquid fuels.

The presence of HeS in gas requires more frequent oil changes.

187
Q

What environmental conditions necessitate more frequent oil changes?

A

Conditions such as heat, dust, or other adversities require more frequent oil changes.

Adverse environments can accelerate oil degradation.

188
Q

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

A

Large capacity sumps can be changed less often.

Larger sumps can hold more oil, which can extend the time between changes.

189
Q

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

A

Centrifuge oil filters help maintain oil quality, often allowing for longer intervals between oil changes.

These filters can remove contaminants effectively.

190
Q

What is the benefit of using synthetic oils in engines?

A

Synthetic oils often allow for longer oil change intervals due to their enhanced properties.

Synthetic oils have better thermal stability and resistance to oxidation.

191
Q

What is the purpose of oil analysis in predictive maintenance?

A

Oil analysis determines the condition of the oil and wear in the engine, indicating when oil requires replacement.

Regular sampling helps in planning maintenance effectively.

192
Q

When should an oil sample be taken for analysis?

A

An oil sample should be taken just prior to an engine shut down.

This prevents sediment from settling out before the sample is collected.

193
Q

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

A

True

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

194
Q

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

A

wear

Regularly scheduled sampling is crucial for effective maintenance.

195
Q

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

A

Lock out the fuel, ignition and starting systems.

196
Q

Why should oil be drained while the engine is warm?

A

Warm oil drains more easily.

197
Q

What should be inspected after removing an engine oil filter?

A

The filter element for metal particles.

198
Q

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

A

Clean the seal surface.

199
Q

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

A

Lubricate it with clean engine oil.

200
Q

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

A

False.

201
Q

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

A

½ to ¾ turn.

202
Q

What should be done after filling the crankcase with oil?

A

Run the pre lube pump briefly to lubricate engine bearings.

203
Q

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

A

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

204
Q

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

A

Oil pressure gauge and inspect for leaks.

205
Q

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

A

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

206
Q

What is a normal reason for oil consumption in engines?

A

Oil lubricating the piston rings and cylinder.

207
Q

What is the primary concern regarding oil consumption?

A

That it is not excessive:

The amount of oil consumed for the size of the engine.

208
Q

How does engine size affect oil consumption?

A

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

209
Q

What factors affect oil pressure?

A

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

210
Q

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

A

Shut down the engine.

211
Q

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

A

Low oil pressure

Common issue that can lead to engine damage if not addressed.

212
Q

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

A

A master oil gauge

It helps to determine if the instrument gauge is faulty.

213
Q

List six main causes of low oil pressure.

A
  • 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

Other causes include worn oil pump, plugged pump strainer, and a stuck open oil pump relief valve.

214
Q

What can change the viscosity of the oil?

A

Fuel or water dilution

This can lead to low oil pressure issues.

215
Q

Is high oil pressure a common problem?

A

No

High oil pressure is less common than low oil pressure.

216
Q

What are three causes of high oil pressure?

A
  • High oil viscosity
  • Relief valve set too high
  • Blockages

These issues can lead to excessive pressure in the system.

217
Q

When is it normal to expect higher oil pressure?

A

When the engine is cold

However, it should not be excessive.

218
Q

What can excessive oil pressure lead to?

A
  • Ruptured oil filters
  • Washed out bearings

These issues can occur if excessive pressure continues for extended periods.

219
Q

What does an oil pressure test indicate?

A

The condition of the oil pump

It provides a partial indication of pump health.

220
Q

What components should be visually inspected on the oil pump?

A
  • Pump housing
  • Cover
  • Gears
  • Shafts
  • Pressure relief valve assembly

Inspection compares wear to limits established by the engine manufacturer.

221
Q

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

A
  • Score marks
  • Worn shaft
  • Cracked housing
  • Teeth pits
  • Checking end play

These signs indicate potential issues with the oil pump components.

222
Q

What is the primary function of the crankcase ventilation system?

A

To remove combustion gases and water vapours from the crankcase

This is essential to prevent issues such as oil foaming and sludge formation.

223
Q

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

A

The escape of combustion gases past the piston rings into the crankcase

This occurs during normal engine operation.

224
Q

What can excessive crankcase pressure lead to?

A

Engine oil seal leaks

This is especially a concern in turbocharged engines.

225
Q

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

A

Formation of sludge

This emulsion can lead to oil foaming if not removed.

226
Q

What does a passive crankcase ventilation system typically include?

A

A breather with a mesh filter and a vent tube

This allows air into the engine and crankcase air to escape to the atmosphere.

227
Q

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

A

False

Crankcase emissions are sent directly to the atmosphere.

228
Q

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

A

Water vapour

This can contribute to the mixing with oil.

229
Q

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

A

water vapours

Removing these prevents sludge formation and oil foaming.

230
Q

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

A

Increased engine wear and damage

This is a risk associated with excessive crankcase pressure.

231
Q

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

A

To ventilate the crankcase and prevent buildup of harmful gases

The PCV system helps in controlling the internal pressure of the crankcase.

232
Q

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

A

Positive pressure or vacuum

Automotive engines typically exhibit positive pressure.

233
Q

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

A

PCV valve

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

234
Q

Where is the PCV line connected in turbocharged engines?

A

Before the turbo

This connection helps manage pressure in the intake manifold.

235
Q

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

A

To remove oil and vapor carryover

This prevents contamination of the turbocharger.

236
Q

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

A

0 to 0.5 inches of water column

This vacuum helps prevent lube oil leaks and crankcase explosions.

237
Q

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

A

By changing the orifice size in the breather line

Adjusting the orifice controls the airflow into the crankcase.

238
Q

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

A

Over-scavenging and oil consumption

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

239
Q

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

A

Orifice

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

240
Q

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

A

Manometer

A manometer can also indicate issues like excessive blowby.

241
Q

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

A

True

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

242
Q

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

A

wire mesh

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

243
Q

What potential engine problems can a crankcase manometer help detect?

A

Leaking rings or scuffed liners

It provides early indications of engine issues related to crankcase pressure.

244
Q

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

A

To atmosphere

245
Q

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

A

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

246
Q

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

A

False

247
Q

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

A

Pneumatic or electric motor

248
Q

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

A

Wax pellet type

249
Q

How are engines with large crossheads lubricated?

A

With oil injected directly into the cylinders.

250
Q

What causes the air to flow through a carburetor?

A

The movement of the piston.

This creates the vacuumm to open the air valve.

251
Q

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

A

Crankshaft fatigue

252
Q

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

A

True.

Looking for the classical detonation in a spark engine.

While diesel is designed to detonate, these questions are asking about which fuel has either the highest or lowest octane rating.

Millwrong (27 decks)

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