Deck 11: Timing Mechanisms

Question 1

Some types of timing chain systems use a composite fiber material for sprockets instead of steel.

Answer 1

True

Question 2

Timing belt sprockets are normally replaced at the same time as a timing belt during maintenance.

Answer 2

False

Question 3

For most modern vehicles, what would be an average range for replacement of a timing belt?

A) 30,000-45,000 miles
B) 90,000-105,000 miles
C) 80,000-125,000 miles
D) 95,000-145,000 miles

Answer 3

B

Question 4

Timing belt systems are typically serviced more often than timing chains.

Question 5

On some engines, it is common practice to install a new water pump during routine replacement of a timing belt.

Question 6

Technician A says that engine performance is enhanced at upper rpm when cam timing is advanced. Technician B says that more valve overlap enhances lower engine rpm. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 7

Timing gears are being discussed. Technician A says that worn timing gears can make noise. Technician B says that the clearance between the gears that is seen by rotating one gear back and forth without the other moving is called backlash. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 8

All of the following are types of camshaft timing devices EXCEPT ____.

A) belt and sprocket
B) gear to gear drive
C) sprockets and chain
D) direct shaft drive

Question 9

Interference engines that have broken timing belts may require extensive repairs such as cylinder head removal to replace valves.

Question 10

Cam timing off by one tooth can affect engine performance.

Question 11

Technician A says that timing components are built with a tolerance that allows + or - one tooth to be aligned improperly during installation. Technician B says that water pumps that are driven by the timing belt need to be timed. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 12

Technician A says that freewheeling engines are not in danger of valve damage due to a broken timing component. Technician B says that balance shafts do not need to be timed to the crankshaft. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 13

Engines with a broken timing belt will crank over at very slow speeds.

Question 14

On cars with timing gears, reduced low-end performance is most likely noticed prior to the gears breaking because of excessive backlash.

Question 15

When a timing chain has broken, the pistons will not move while cranking.

Question 16

Timing chains are being discussed. Technician A says that timing chains can be checked by measuring chain deflection. Technician B says that rotating the crankshaft without camshaft movement while the engine is still together can indicate the amount of wear. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 17

Technician A says that improper valve timing can affect cylinder compression. Technician B says that a timing belt that is off by one tooth can affect valve lift. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 18

Timing belts are being discussed. Technician A says that a timing belt is designed and shaped just like a serpentine belt. Technician B says that timing belts that are adjusted too tight may whine.

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 19

When servicing a timing belt, to rotate the engine easily and without damage you should use the center bolt on the camshaft sprocket.

Question 20

Technician A says that a crankshaft must make two full rotations for the camshaft to make one. Technician B says that some engines vary the valve timing during operation to increase performance. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 21

Technician A says all VVT system change both the intake and exhaust valve timing. Technician B says a VVT system may operate on either the intake, exhaust, or both cams. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 22

Technician A says hydraulic pressure from engine oil is a component of variable valve timing. Technician B says that some variable valve timing systems use a timing chain and gears as the main drive system. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 23

What main two timing components, not including tensioner and guides, are usually replaced with a timing chain?

Question 24

A car is towed into a shop because of a cranks but will not start condition. While cranking the engine, the engine spins faster than normal and backfires in the intake manifold and exhaust. Technician A says that the engine may have jumped out of camshaft timing. Technician B says that the timing gears may have too much backlash. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 25

What is the best indicator to tell when a timing belt is worn and needs to be replaced?

Question 26

When setting the timing on an engine, what could be set wrong that will not prevent the engine from running, but will cause vibrations?

Question 27

A vehicle with an OHC driven by chain and sprockets is brought into a shop for a noise. While running, a slapping sound is heard from the timing cover. Technician A says that the timing chain may be hitting the cover and this should be addressed right away. Technician B says that timing chains need periodic adjustment and this noise can be corrected without disassembly. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 28

While listening to an engine that will crank but not run, what would be the difference in sound between an engine with a broken timing belt and one that has jumped timing?

Question 29

What is the best place to rotate an engine from during service?

Question 30

All of the following can be accomplished with variable valve timing while the engine is running EXCEPT ____.

A) altering engine displacement
B) changing valve overlap
C) changing cam timing
D) improving emissions

Question 31

VVT systems can be used for which of the following purposes?

A) Vary valve timing
B) Vary valve lift
C) Vary valve duration
D) All of the above

Question 32

Where may the camshaft be placed on timing chain systems?

Question 33

Why are gear to gear timing components set with a small amount of backlash from the factory?

Question 34

Which is not an advantage of gear-to-gear timing mechanisms?

A) Timing accuracy
B) Increased durability
C) Decreased noise
D) Eliminated belt/chain slack

Question 35

The timing components are being inspected on a chain system with composite sprockets. The sprockets are very worn and are missing teeth. What should be removed, inspected, and cleaned due to the missing teeth?

Question 36

Timing belt/chain tensioners can be operated in all of the following methods except:

A) Oil feed from lubrication system
B) Spring tensioned
C) Silicone oil filled hydraulic tensioners
D) Cooling system fed hydraulic tensioners

Question 37

How many teeth off can a timing system be set up with so that no problems are encountered?

Question 38

What will a compression and a vacuum test show on an engine that has jumped timing?

Question 39

Technician A says all late model multi-valve engines are interference engines. Technician B says both inline and V-block engines can be interference engines. Who is correct?

A) Technician A
B) Technician B
C) Both A and B
D) Neither A nor B

Question 40

Technician A says that timing gear noises are affected by engine load. Technician B says that belt noises are affected by engine load. Who is correct?

A) A only
B) B only
C) Both A and B
D) Neither A nor B

Question 41

All of the following are advantages of VVT systems except:

A) Increased performance
B) Increased emissions
C) Increased fuel economy
D) Allows us of smaller engine size

Question 42

Explain how a simple displacement-on-demand system improves fuel economy.

Question 43

Explain what a technician would look for during a visual inspection of a timing belt.

Question 44

Describe how a variable displacement (or displacement on demand) lifter works to deactivate a cylinder.

Question 45

What are the advantages a timing belt has over other systems?

Question 46

Engines with VTEC (variable timing electronic control) vary the valve duration to increase engine performance.

Question 47

When should timing chain guides be replaced?

Question 48

Explain what can happen to an interference engine when the timing mechanism breaks.

Question 49

Improper type of oil or lack of lubrication system maintenance can cause damage to a displacement on demand system.

Question 50

How would a timing chain system be inspected for wear on an assembled engine?

Question 51

In many displacement-on-demand engines, the PCM controls cylinder deactivation by using specially controlled:

A) Valves
B) Camshaft lobes
C) Lifters
D) Pistons

Question 52

What emission control device is used to cool combustion and reduce oxides of nitrogen?

Question 53

A VVT system can keep the intake valves open for a longer __________ and thus produce more power.

Question 54

Variable cam timing is used to:

A) Allow high duration at high rpm
B) Allow high duration at low rpm
C) Both A and B
D) Neither A nor B