Crucial Engine pt. 1 Points

Question 1

What does an engine lubrication system fitted with a relief valve do?

Answer 1

Limit the maximum oil pressure to the bearings

Question 2

What does viscosity mean in terms of oil?

Answer 2

Oil density

Question 3

What measurement tool is used to check coolant for the anti-freeze content?

Answer 3

Hydrometer

Question 4

Why is it important to maintain engine valve clearance?

Answer 4

It effects engine power

Question 5

What engine oil is most suitable for a modern CI engine?

Answer 5

SAE5W/40

Question 6

What is a semi-synthetic lubricant?

Answer 6

A mixture of organic and man-made lubricants

Question 7

What is the name given to an engine without a pressure-charger induction system?

Answer 7

Naturally aspirated

Question 8

What does a rotary engine have?

Answer 8

An epitrochoidal liner which turns a triangular rotar

Question 9

When does maximum compression occur?

Answer 9

At TDC

Question 10

If valve clearances are too large, when will the valves open and close?

Answer 10

Open later and close earlier

Question 11

How does heat from the engine cylinder pass through the cylinder walls?

Answer 11

Conduction

Question 12

In the diagram with the circle and the x at the top, what does the x represent?

Answer 12

The valve overlap

Question 13

What could the problem be if there are air bubbles in the cooling system when the engine is running?

Answer 13

Blown head gasket

Question 14

What are the 3 most likely causes of high fuel consumption?

Answer 14

Excessively worn piston rings, valves or gaskets

Question 15

When replacing a blown cylinder head gasket what is it important to do?

Answer 15

Check the cylinder head for distortion

Question 16

What is water in the engine oil is most likely caused by?

Answer 16

Defective liner seals

Question 17

What is a likely symptom of a blown head gasket?

Answer 17

Poor engine performance and engine overheating

Question 18

A compression ignition engine emits blue smoke when under load. What is the most likely cause?

Answer 18

Broken piston rings

Question 19

Which component needs to be removed when fitting a cylinder compression gauge to a spark ignition engine?

Answer 19

Spark plug

Question 20

Where is the oil stored in a wet sump lubrication system?

Answer 20

Engine sump

Question 21

What is the distance between BDC and TDC related to?

Answer 21

The stroke

Question 22

When refitting a piston to a compression ignition engine, how should the gaps in the piston ring be spaced?

Answer 22

120 degrees apart with no gaps facing the thrust surface

Question 23

What is the purpose of cylinder honing or ‘glaze busting’?

Answer 23

To remove the highly polished surface from the cylinder

Question 24

Why are supplemental coolant additives (SCA) sometimes added to CI engines?

Answer 24

Decrease the cavitation point of coolant

Question 25

Which measurement requires a precision straight edge and feeler gauge?

Answer 25

Checking for cylinder head warp

Question 26

What is a normal compression ratio of a CI engine?

Answer 26

16:1 to 22:1

Question 27

In what type of CI engine is the combustion chamber machined into the piston crown?

Answer 27

Direct injection

Question 28

When stripping an engine, you are asked to find out its cubic capacity, which action would assist you to find the correct answer?

Answer 28

Measure the bore, the distance the piston moves from BDC to TDC and count the number of cylinders

Question 29

What formula can be used to calculate compression ratio?

Answer 29

Swept volume + clearance volume / clearance volume

Question 30

What is the main difference between a wet sump and dry sump lubrication system?

Answer 30

A wet sump requires an external oil supply tank and a scavenge pump

Question 31

In a full flow lubrication system, what order of components does the oil flow through?

Answer 31

Filter first, then something else

Question 32

What is specific heat capacity?

Answer 32

The quantity of heat required to raise the temperature of 1kg of a substance by 1K or 1 degree C

Question 33

What are the unit abbreviations used to show engine power and torque?

Answer 33

KW and Nm

Question 34

What should you do to determine piston clearance accurately?

Answer 34

Don’t slide a feeler gauge between the piston and cylinder

Question 35

What is the suitable oil viscosity for a modern petrol engine?

Answer 35

SAE 10/40

Question 36

A coolant leak from behind the dashboard could suggest what?

Answer 36

A leaking heater matrix