Engines 101

torque

rotating force

pound-feet

torque is expressed in units of ____

Technician A only

Technician A says that a crankshaft determines the stroke of an engine. Technician B says that the length of the connecting rod determines the stroke of an engine. Which technician is correct?

720 degrees

One cylinder of an automotive four-stroke cycle engine completes a cycle every ______

thermostat

The coolant flow through the radiator is controlled by the _______________.

Indirect Injection(IDI)

Which diesel injection system requires the use of a glow plug?

Ignition delay, rapid combustion, controlled combustion

what are the 3 phases of diesel ignition?

gear off the camshaft

The diesel injection pump is usually driven by a _______

indirect injection

Which type of diesel injection produces less noise?

Water-fuel separator

What fuel system component is used in a vehicle equipped with a diesel engine that is not usually used on the same vehicle when it is equipped with a gasoline engine?

Both A and B

Two technicians are discussing testing coolant for proper pH. Technician A says that coolant has a pH above 7 when new and becomes lower with use in an engine. Technician B says that OAT and HOAT coolants have a lower pH when new compared to the old green IAT coolant. Which technician is correct?

ethylene glycol

Coolant is water and _______

Technician. B only

A voltmeter was used to check the coolant and a reading of 0.2 volt with the engine off was measured. A reading of 0.8 volts was measured with the engine running and all electrical accessories turned on. Technician A says that the coolant should be flushed to solve the galvanic activity. Technician B says that the ground wires and connections should be inspected and repaired to solve the electrolysis problem. Which technician is correct?

Embittered

Adding a chemical to make ethylene glycol coolant bitter to the taste is called __________

HOAT

Asian red coolant is what type?

A defective pressure cap

The. upper radiator collapses when the engine cools. What is the most likely cause

195º to 215ºF

The normal operating temperature (coolant temperature) of an engine equipped with a 195'F thermostat is______.

P0128

What diagnostic trouble code (DTC) could be set if the thermostat is defective?

False

A water pump is a positive displacement-type pump.

Group

Most conventional (mineral) oil is made from what API group?

 

Are maximum time and mileage intervals

Oil change intervals as specified by the vehicle manufacturer ________.

 Both Technicians A and B

Technician A says that the engine oil used should be meet the vehicle manufacturer’s standards. Technician B says that the specified viscosity of oil be used. Which technician is correct?

miscible

Different brands or oil can be used in a vehicle from one oil change to another if they meet the vehicle specification because all oil is _______.

ZDDP(Zinc)

Older engines that use flat bottom lifers should use oil (or an additive) that has enough______

Both Technicians A and B

Two technicians are discussing oil pumps. Technician A says that many oil pumps are driven directly off the front of the crankshaft. Technician B says that some are driven from the distributor if the engine uses a distributor-type ignition system. Which technician is correct?

galleries

Oil passages in an engine block are usually called ____________.

Coolant

Engine oil cooler uses what to cool the oil?

1000 psi

Hydrodynamic lubricants, created by the wedging action of oil between the crankshaft journal and the bearing, can be as high as _______ psi.

• It allows the vehicle to corner or brake for long periods

• Allows the engine to develop more power

• Allows for a greater oil capacity so that oil temperatures can be controlled.

A dry sump system is used in some high-performance vehicles because:

Both Technicians

Technician A says that a cracked exhaust manifold can affect engine operation. Technician B says that a leaking lower intake manifold gasket could cause a vacuum leak. Which technician is correct?

amount of restriction measured in inches of water

The air filter restriction indicator uses what to detect when it signals to replace the filter?

Cool exhaust gas is more effective at controlling NOX emissions

Why are the EGR gases cooled before entering the engine on some engines?

plenum

The upper portion of a two-part intake manifold is often called the ______________.

Both Techs

Exhaust passages are included in some intake manifolds. Technician A says that the exhaust passages are used for exhaust gas recirculation (EGR) systems. Technician B says that the upper intake is often called the plenum. Which technician is correct?

bypass valve

Which valve is used on a factory supercharger to limit boost?

tech b

Technician A says that a stuck-open wastegate can cause the engine to burn oil. Technician B says that a clogged PCV system can cause the engine to burn oil. Which technician is correct?

• dump valve

• BOV

Which type of relief valve used on a turbocharged engine is noisy?

internal oil reservoir

How are most superchargers lubricated?

• roots type

• centrifugal

Two types of superchargers include ____________.

both techs

Two technicians are discussing oil leaks. Technician A says that an oil leak can be found using a fluorescent dye in the oil with a black light to check for leaks. Technician B says that a white spray powder can be used to locate oil leaks. Which technician is correct?

both techs

Technician A says that a leaking head gasket can be checked using a chemical tester. Technician B says that a leaking head gasket can be found using an exhaust analyzer. Which technician is correct?

both techs

Technician A says that the paper test could detect a burned valve. Technician B says that a grayish white stain on the engine could be a coolant leak. Which technician is correct?

2.5 inches Hg or higher

Cranking vacuum should be ________.

tech b

Technician A says that during a power balance test, the cylinder that causes the biggest RPM drop is the weak cylinder. Technician B says that if one spark plug wire is grounded out and the engine speed does not drop, a weak or dead cylinder is indicated. Which technician is correct?

• stuck open

• stuck closed

• stuck partially open

A thermostat can fail in which way?

working, but not at the correct temperature

A skewed thermostat means it is _____________.

disposed of properly or recycled

Coolant drained from the cooling system when replacing a thermostat or water pump should be ____________.

• tensioner assembly

• water pump

• camshaft oil seals

When replacing a timing belt, many experts and vehicle manufacturers recommend that what other part(s) should be replaced?

• fretting

• coolant damage

• relative movement between the intake manifold and the cylinder head

Intake manifold gaskets on a V-type engine can fail due to what factor?

60-90psi

A good engine should produce how much compression during a running (dynamic) compression test?

water based

Aqueous-based cleaning means________.

• 600ºF for aluminum parts 

• 800ºF for cast iron

A pyrolytic oven is used to clean parts; however, caution should be used to limit the temperature, to prevent damaging engine parts. What are the maximum recommended temperatures?

• heat from the steam

• abrasives used

What actually does the cleaning when using steam?

 

An acid is lower than 7 and a caustic is higher than 7 on the pH scale.

Cleaning chemicals are usually either a caustic material or an acid material. Which of the following statements is true?

a. Both caustics and acids have a pH of 7 if rated according to distilled water .

b. An acid is lower than 7 and a caustic is higher than 7 on the pH scale.

c. An acid is higher than 7 and a caustic is lower than 7 on the pH scale.

d. Pure water is a 1 and a strong acid is a 14 on the pH scale.

 

Uses a fine iron powder to detect cracks in iron parts

Magnetic crack inspection ________.

tech a

Two technicians are discussing a Hemi engine. Technician A says that a Hemi is an engine with a hemispherical-shaped combustion chamber. Technician B says that all Hemi engines are cam-in-block designs. Which technician is correct?

• increase the velocity of the air

• they have a greater open area

Cylinder heads with four valves flow more air than those with two valves because ________.

 

0.002 inch in any 6-inch length or 0.004 inch overall

The gasket surface of a cylinder head, as measured with a precision straightedge, should have a maximum variation of ________.

the rougher the surface, the higher the microinch finish measurement

Which statement is true about surface finish?

 

Heating it in an oven at 500?F with shims under each end, allowing it to cool, and then machining it.

A warped aluminum cylinder head can be restored to useful service by ________.

45º

To lower and narrow a valve seat that has been cut at a 45-degree angle, use a cutter or stone of what angle?

1º

If an interference angle is machined on a valve or seat, this angle is usually ________.

fit tightly onto the valve stem

Umbrella-type valve stem seals ________.

prevent valve spring surge

Dampers (damper springs) are used inside some valve springs to ________.

0.002in

A valve seat should be concentric to the valve guide to a maximum TIR of ___________.

overlap is 86

The intake valve opens at 39? BTDC and closes at 71? ABDC. The exhaust valve opens at 78? BBDC and closes at 47? ATDC. Which answer is correct?

Both Techs

Two technicians are discussing variable valve timing. Technician A says that changing the exhaust valve timing helps reduce exhaust emissions. Technician B says that changing the intake valve timing helps increase low-speed torque. Which technician is correct?

4 camshafts

A DOHC V-6 has how many camshafts?

all the dirt can’t be cleaned from the hollow center

Many technicians always use new pushrods because ______________________.

taper of the lobe

Flat-bottom valve lifters rotate during operation because of the _____ of the camshaft.

pulse width modulated (PWM) signal

how si the camshaft actuator controlled

exhaust camshaft

To reduce oxides of nitrogen(NOX) exhaust emissions, which camshaft is varied?

• DOHC

• Cam-in-block

• SOHC

Variable valve timing can be found on which type of engine?