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A/C Maintenance > Reciprocating Engines > Flashcards

Reciprocating Engines Flashcards

1
Q
  1. When is the fuel/air mixture ignited in a conventional reciprocating engine?

a. When the piston has reached top dead center of the intake stroke.
b. Shortly before the piston reaches the top of the compression stroke.
c. When the piston reaches top dead center on the compression stroke.

A

b.

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2
Q
  1. Direct mechanical push-pull carburetor heat control linkages should normally be adjusted so that the stop located on the diverter valve will be contacted

a. before the stop at the control lever is reached in both HOT and COLD positions.
b. before the stop at the control lever is reached in the HOT position and after the stop at the control lever is reached in the COLD position
c. after the stop at the control lever is reached in both HOT and COLD positions.

A

a.

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3
Q
  1. At what speed must a crankshaft turn if each cylinder of a four-stroke cycle engine is to be fired 200 times a minute?

a. 800 RPM
b. 1,600 RPM
c. 400 RPM

A

c.

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4
Q
  1. Excessive valve clearance in a piston engine

a. increases valve overlap
b. increases valve opening time
c. decreases valve overlap

A

c.

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5
Q
  1. On which part of the cylinder walls of a normally operating engine will the greatest amount of wear occur?

a. Near the center of the cylinder where piston velocity is greatest
b. Near the top of the cylinder
c. Wear is normally evenly distributed

A

b.

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6
Q
  1. During the inspection of an engine control system in which push-pull control rods are used, the threaded rod ends should

a. insure that the safety wire passes thru the hole in shank of the rod-end
b. be checked for the thread engagement of at least two threads but more than four threads.
c. be checked for the amount of thread engagement by means of the inspection holes

A

c.

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7
Q
  1. Some aircraft engine manufacturers equip their product with choked or taper-ground cylinders in order to

a. Provide a straight cylinder bore at operating temperatures.
b. Flex the rings slightly during operation and reduce the possibility of the rings sticking in the grooves.
c. Increase the compression pressure for starting purposes.

A

a.

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8
Q
  1. An unsupercharged aircraft reciprocating engine, operated at full throttle from sea level, to 10,000 feet, provided the RPM is unchanged, will

a. Lose power due to the reduced volume of air drawn into the cylinders.
b. Produce constant power due to the same volume of air drawn into the cylinders.
c. Lose power due to the reduce density of the air drawn into the cylinders.

A

c.

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9
Q
  1. As the pressure is applied during a reciprocation engine compression check using a differential pressure tester, what would a movement of the propeller in the direction of engine rotation indicate?

a. The piston was on compression stroke.
b. The piston was on exhaust stroke.
c. The piston was positioned past top dead center.

A

c.

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10
Q
  1. The valve clearance of an engine using hydraulic lifters, when the lifters are completely flat, or empty, should not exceed

a. 0.00 inch
b. a specified amount above zero
c. a specified amount below zero

A

b.

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11
Q
  1. What does valve overlap promote?

a. Lower intake manifold pressure and temperatures.
b. A backflow of gases across the cylinder.
c. Better scavenging and cooling characteristics.

A

c.

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12
Q
  1. During ground check and engine is found to be rough-running, the magneto drop is normal, and the manifold pressure is higher than normal for any given RPM. The trouble may be caused by

a. Several spark plugs fouled on different cylinders
b. A leak in the intake manifold
c. A dead cylinder

A

c.

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13
Q
  1. During routine inspection of a reciprocating engine, a deposit of small, bright, metallic particles which do not cling to the magnetic drain plug is discovered in the oil sump and on the surface of the oil filter. This condition

a. may be a result of abnormal plain type bearing wear and is cause for further investigation.
b. is probably a result of ring and cylinder wall wear and is cause for engine removal and/or overhaul.
c. is normal in engines utilizing plain type bearings and aluminum pistons and is not cause for alarm.

A

a.

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14
Q
  1. Master rod bearings are generally what type?

a. Plain
b. Roller
c. Ball

A

a.

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15
Q
  1. A hissing sound from the exhaust stacks when the propeller is being pulled through manually indicates

a. a cracked exhaust stack
b. exhaust valve blow-by
c. worn piston rings

A

b.

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16
Q
  1. If the exhaust valve of a four-stroke cycle engine is closed and the intake valve is just closed, the piston is on the

a. intake stroke
b. power stroke
c. compression stroke

A

c.

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16
Q
  1. If the exhaust valve of a four-stroke cycle engine is closed and the intake valve is just closed, the piston is on the

a. intake stroke
b. power stroke
c. compression stroke

A

c.

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17
Q
  1. When will small induction system air leaks have the most noticeable effect on engine operation?

a. At high RPM
b. At maximum continuous and takeoff power settings
c. At low RPM

A

c.

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18
Q
  1. What special procedure must be followed when adjusting the values of an engine equipped with a floating cam ring?

a. Adjust valves when the engine is hot.
b. Adjust all exhaust valves before intake valves.
c. Eliminate cam bearing clearance when making valve adjustment.

A

c.

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19
Q
  1. Valve overlap is defined as the number of degrees of crankshaft travel

a. during which both valves are off their seats.
b. between the closing of the intake valve and the opening of the exhaust valve.
c. during which both valves are on their seats.

A

a.

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20
Q
  1. Which of the following engine servicing operations generally requires engine pre-oiling prior to starting the engine?

a. Engine oil and filter change
b. Engine installation
c. Replacement of oil lines

A

b.

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21
Q
  1. What is the best indication of worn valve guides?

a. High oil consumption
b. Low compression
c. Low oil pressure

A

a.

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22
Q
  1. How may it be determined that a reciprocating engine with a dry sump is pre-oiled sufficiently?

a. The engine oil pressure gauge will indicate normal oil pressure.
b. Oil will flow from engine return line or indicator port.
c. When the quantity of oil specified by the manufacturer has been pumped into the engine.

A

b.

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23
Q
  1. If air is heard coming from the crankcase breather or oil filler during a differential compression check, what is this an indication of?

a. Exhaust valve leakage
b. Intake valve leakage
c. Piston ring leakage

A

c.

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24
Q
  1. Excessive valve clearances will cause the duration of valve opening to

a. increase for both intake and exhaust valves
b. decrease for both intake and exhaust valves
c. decrease for intake valves and decrease for exhaust valves

A

b.

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25
Q
  1. Which statement is correct regarding a four-stroke cycle aircraft engine?

a. The intake valve closes on the compression stroke
b. The exhaust valve opens on the exhaust stroke
c. The intake valve closes on the intake stroke

A

a.

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26
Q
  1. A characteristic of dyna-focal engine mounts as applied to aircraft reciprocating engines is that the

a. shock mounts eliminate the torsional flexing of the powerplant.
b. engine attaches to the shock mount at the engine’s center of gravity.
c. shock mount point toward the engine’s center of gravity.

A

c.

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27
Q
  1. Which statement pertaining to fuel/air ratios is true?

a. The mixture ratio which gives the best power is richer than the mixture ratio which gives the maximum economy.
b. A rich mixture is faster burning than a normal mixture.
c. The mixture ratio which gives maximum economy may also be designated as best power mixture.

A

a.

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27
Q
  1. Which statement pertaining to fuel/air ratios is true?

a. The mixture ratio which gives the best power is richer than the mixture ratio which gives the maximum economy.
b. A rich mixture is faster burning than a normal mixture.
c. The mixture ratio which gives maximum economy may also be designated as best power mixture.

A

a.

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28
Q
  1. One cause of afterfiring in an aircraft engine is

a. sticking intake valves
b. an excessively lean mixture
c. an excessively rich mixture

A

c.

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29
Q
  1. The horsepower developed in the cylinders of a reciprocating engine is known as the

a. shaft horsepower
b. indicated horsepower
c. brake horsepower

A

b.

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30
Q
  1. An increase in manifold pressure with a constant RPM will cause the bearing load in an engine to

a. decrease
b. remain relatively constant
c. increase

A

c.

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31
Q
  1. Which of the following will decrease volumetric efficiency in a reciprocating engine?
    (1) Full throttle operation
    (2) Low cylinder head temperatures
    (3) Improper valve timing
    (4) Sharp bends in the induction system
    (5) High carburetor air temperatures

a. 2, 4 and 5
b. 1, 2, 3 and 4
c. 3, 4 and 5

A

c.

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32
Q
  1. A nine-cylinder engine with a bore of 5.5 inches and a stroke of 6 inches will have a total piston displacement of

a. 740 cubic inches
b. 1,425 cubic inches
c. 1,283 cubic inches

A

c. (Formula = ((pi x bore^2 x stroke) / 4) x no. of cylinders

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33
Q
  1. The primary purpose in setting proper valve timing and overlap is to

a. permit the best possible charge of fuel/air mixture into the cylinders.
b. gain more thorough exhaust gas scavenging.
c. obtain the best volumetric efficiency and lower cylinder operating temperatures.

A

c.

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34
Q
  1. Engine crankshaft runout is usually checked
    (1) during engine overhaul
    (2) during annual inspection
    (3) after a “prop strike” or sudden engine stoppage
    (4) during 100-hour inspection

a. 1, 3, and 4
b. 1 and 3
c. 1, 2, and 3

A

b.

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35
Q
  1. A condition that can occur in radial engines but is unlikely to occur in horizontally opposed engines is

a. oil-fouled spark plug
b. valve overlap
c. hydraulic lock

A

c.

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36
Q
  1. Which statement is true regarding bearings used in high-powered reciprocating aircraft engines?

a. The outer race of a single-row, self-aligning ball bearing will always have a radius equal to the radius of the balls.
b. There is less rolling friction when ball bearings are used than when roller bearings are employed.
c. Crankshaft bearings are generally of the ball-type due to their ability to withstand extreme loads without overheating.

A

b.

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37
Q
  1. Excessive valve clearances results in the valves opening

a. late and closing early
b. early and closing late
c. late and closing late

A

a.

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38
Q
  1. What will be the likely result if the piston ring gaps happen to be aligned when performing a differential-pressure compression check on a cylinder?

a. Little or no effect
b. The rings will not be seated
c. A worn or defective ring(s) indication

A

c.

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39
Q
  1. Engine operating flexibility is the ability of the engine to

a. deliver maximum horsepower at a specific altitude
b. meet exacting requirements of efficiency and low weight per horsepower ratio
c. run smoothly and give the desired performance at all speeds

A

c.

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40
Q
  1. An engine misses in both the right and left positions of the magneto switch. The quickest method for locating the trouble is to

a. check for one or more cold cylinders
b. perform a compression check
c. check each spark plug

A

a.

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41
Q
  1. After spark plugs from an opposed engine have been serviced, in what position should they be reinstalled?

a. Next in firing order to the one from which they were removed
b. Swapped from bottom to top
c. Next in firing order to the one from which they were removed and swapped bottom to top

A

c.

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42
Q
  1. Grinding the valves of a reciprocating engine to a feather edge is likely to result in

a. normal operation and long life
b. excessive valve clearance
c. preignition and burned valves

A

c.

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43
Q
  1. Which of these conditions will cause an engines to have an increased tendency to detonate?
    (1) High manifold presssure
    (2) High intake air temperature
    (3) Engine overheated
    (4) Late ignition timing

a. 1, 2, 3
b. 1, 2, 3, 4
c. 1, 4

A

a.

44
Q
  1. Standard aircraft cylinder oversizes usually range from 0.010 inch to 0.030 inch. Oversize on automobile engine cylinders may range up to 0.100 inch. This is because aircraft engine cylinders

a. have more limited cooling capacity
b. have relatively thin walls and may be nitrided
c. operate at high temperatures

A

b.

45
Q
  1. The purpose of two or more valve springs in aircraft engines is to

a. equalize side pressure on the valve stems
b. eliminate valve spring surge
c. equalize valve face loading

A

b.

46
Q
  1. What could cause excessive pressure buildup in the crankcase of a reciprocating engine?

a. Plugged crankcase breather
b. Improper warmup operation
c. An excessive quantity of oil

A

a.

47
Q
  1. By use of a differential pressure compression tester, it is determined that the No. 3 cylinder of a nine-cylinder radial engine will not hold pressure after the crankshaft has been rotated 2600 from top dead center compression stroke No. 1 cylinder. How can this indication usually be interpreted?

a. A normal indication
b. Exhaust valve blow-by
c. A damaged exhaust valve or insufficient exhaust valve clearance

A

a.

48
Q
  1. One of the best indicators of reciprocating engine combustion chamber problems is

a. excessive engine vibration
b. starting difficulties
c. spark plug condition

A

c.

49
Q
  1. If the ignition switch is moved from BOTH to either LEFT or RIGHT during a magneto check, a normal operation is usually indicated by

a. no change in RPM
b. momentary interruption of both ignition systems
c. slight drop in RPM

A

c. (parang sa runup)

50
Q
  1. The primary concern in establishing the firing order for an opposed engine is

a. provide for balance and eliminate vibration to the greatest extent possible
b. keep power impulses on adjacent cylinders as far apart as possible in order to obtain the greatest mechanical efficiency.
c. keep the power impulses on adjacent cylinders as close as possible in order to obtain the greatest mechanical efficiency

A

a.

50
Q
  1. The primary concern in establishing the firing order for an opposed engine is

a. provide for balance and eliminate vibration to the greatest extent possible
b. keep power impulses on adjacent cylinders as far apart as possible in order to obtain the greatest mechanical efficiency.
c. keep the power impulses on adjacent cylinders as close as possible in order to obtain the greatest mechanical efficiency

A

a.

51
Q
  1. Increased water vapor (higher relative humidity) in the incoming air to a reciprocating engine will normally result in which of the following?

a. Decreased engine power at a constant RPM and manifold pressure
b. Increased power output due to increased volumetric efficiency
c. A leaning effect on engines which use non-automatic carburetors

A

a.

52
Q
  1. If the hot clearance is used to set the valves when the engine is cold, what will occur during operation of the engine?

a. The valves will open early and close early
b. The valves will open late and close early
c. The valves will open early and close late

A

b.

53
Q
  1. Which fuel/air mixture will result in the highest engine temperature (all other factors remaining constant)?

a. A mixture leaner than a rich best-power mixture of .085
b. A mixture richer than a full-rich mixture of .087
c. A mixture leaner than a manual lean mixture of .060

A

c.

54
Q
  1. What is the principal advantage of using propeller reduction gears?

a. To enable the propeller RPM to be increased without an accompanying increase in engine RPM
b. To enable the engine RPM to be increased with an accompanying increase in power and allow the propeller to remain at a lower, more efficient RPM
c. To enable the engine RPM to be increased with an accompanying increase in propeller RPM

A

b.

55
Q
  1. Which bearing is least likely to be a roller or ball bearing?

a. Rocker arm bearing (overhead valve engine)
b. Master rod bearing (radial engine)
c. Crankshaft main bearing (radial engine)

A

b.

55
Q
  1. Which bearing is least likely to be a roller or ball bearing?

a. Rocker arm bearing (overhead valve engine)
b. Master rod bearing (radial engine)
c. Crankshaft main bearing (radial engine)

A

b.

56
Q
  1. On which strokes are both valves on a four-stroke cycle reciprocating aircraft engine open?

a. Power and exhaust
b. Intake and compression
c. Exhaust and intake

A

c.

57
Q
  1. To reduce the power output of an engine equipped with a constant-speed propeller and operating near maximum BMEP, the

a. manifold pressure is reduced with the throttle control before the RPM is reduced with the propeller control
b. manifold pressure is reduced with the propeller control before the RPM is reduced with the throttle control
c. RPM is reduced with the propeller control before the manifold pressure is reduced with the throttle control

A

a.

58
Q
  1. Which of the following would indicate a general weak-engine condition when operated with a fixed-pitch propeller or test club?

a. Lower than normal static RPM, full throttle operation
b. Manifold pressure lower at idle RPM than at static RPM
c. Lower than normal manifold pressure for any given RPM

A

a.

59
Q
  1. Some cylinder barrels are hardened by

a. nitriding
b. shot peening
c. tempering

A

a.

60
Q
  1. Why does the smoothness of operation of an engine increase with a greater number of cylinders?

a. The power impulses are spaced closer together
b. The power impulses are spaced farther apart
c. The engine has larger counterbalance weights

A

a.

61
Q
  1. Which of the following is a characteristic of a thrust bearing used in most radial engines?

a. Tapered roller
b. Double-row ball
c. Deep-groove ball

A

c.

62
Q
  1. Which condition would be the least likely to be caused by failed or failing engine bearings?

a. Excessive oil consumption
b. High oil temperatures
c. Low oil temperatures

A

c.

63
Q
  1. Valve clearance changes on opposed-type engines using hydraulic lifters are accomplished by

a. rocker arm adjustment
b. rocker arm replacement
c. push rod replacement

A

c.

64
Q
  1. The floating control thermostat, used on some reciprocating engine installations, helps regulate oil temperature by

a. controlling oil flow through the oil cooler
b. recirculating hot oil back through the sump
c. controlling air flow through the oil cooler

A

c.

65
Q
  1. Which of the following would most likely cause a reciprocating engine to backfire through the induction system at low RPM operation?

a. Idle mixture too rich
b. Clogged derichment valve
c. Lean mixture

A

c.

66
Q
  1. What is the purpose of a power check on a reciprocating engine?

a. To check magneto drop
b. To determine satisfactory performance
c. To determine if the fuel/air mixture is adequate

A

b.

67
Q
  1. To what altitude will a turbo charged engine maintain sea level pressure?

a. Critical altitude
b. Service ceiling
c. Pressure altitude

A

a.

68
Q
  1. Before attempting to start a radial engine that has been shut down for more than 30 minutes,

a. turn the propeller by hand three or four revolutions in the opposite direction of normal rotation to check for liquid lock
b. turn the ignition switch on before energizing the starter
c. turn the propeller by hand three to four revolutions in the normal direction of rotation to check for liquid lock

A

c.

69
Q
  1. If the crankshaft runout readings on the dial indicator are plus .002 inch and minus .003 inch, the runout is

a. .005 inch
b. plus .001 inch
c. minus .001 inch

A

a.

70
Q
  1. Full-floating piston pins are those which allow motion between the pin and

a. the piston
b. both the piston and the large end of the connecting rod
c. both the piston and the small end of the connecting rod

A

c.

71
Q
  1. During overhaul, the disassembled parts of an engine are usually degreased with some form of mineral spirits solvent rather than water-mixed degreasers primarily because

a. solvent degreasers are much more effective
b. water-mixed degreaser residues may cause engine oil contamination in the overhauled engine
c. water-mixed degreasers cause corrosion

A

b.

72
Q
  1. When does valve overlap occur in the operation of an aircraft reciprocating engine?

a. At the end of the exhaust stroke and the beginning of the intake stroke
b. At the end of the power stroke and the beginning of the exhaust stroke
c. At the end of the compression stroke and the beginning of the power stroke

A

a.

73
Q
  1. Which statement is correct regarding engine crankshafts?

a. Moveable counterweights serve to reduce the dynamic vibrations in an aircraft reciprocating engine
b. Moveable counterweights serve to reduce the torsional vibrations in an aircraft reciprocating engine
c. Moveable counterweights are designed to resonate at the natural frequency of the crankshaft

A

b.

74
Q
  1. The volume of a cylinder equals 70 cubic inches when the piston is at bottom center. When the piston is at the top of the cylinder, the volume equals 10 cubic inches. What is the compression ratio?

a. 1:7
b. 7:10
c. 7:1

A

c.

75
Q
  1. Which of the following is most likely to occur if an overhead valve engine is operated with inadequate valve clearances?

a. The valves will not seat positively during start and engine warmup.
b. The further decrease in valve clearance that occurs as engine temperatures increase will cause damage to the valve-operating mechanism.
c. The valves will remain closed for longer periods than specified by the engine manufacturer

A

a.

76
Q
  1. If metallic particles are found in the oil filter during an inspection,

a. It is an indication of normal engine wear unless the particles are nonferrous.
b. The cause should be identified and corrected before the aircraft is released for flight.
c. It is an indication of normal engine wear unless the deposit exceeds a specified amount.

A

b.

77
Q
  1. The five events of a four-stroke cycle engine in the order of their occurrence are

a. intake, ignition, compression, power, exhaust
b. intake, power, compression, ignition, exhaust
c. intake, compression, ignition, power, exhaust

A

c.

78
Q
  1. Ignition occurs at 28 degrees BTDC on a certain four-stroke cycle engine, and the intake valve opens at 15 degrees BTDC. How many degrees of crankshaft travel after ignition does the intake valve open? (Consider one cylinder only.)

a. 707 degrees
b. 373 degrees
c. 347 degrees

A

b.

79
Q
  1. What is required by 14 CFR Part 43 Appendix D when performing an annual/100-hour inspection on a reciprocating engine aircraft?

a. Magneto timing check
b. Cylinder compression check
c. Valve clearance check

A

b.

80
Q
  1. Backfiring through the carburetor generally results from the use of

a. an excessively lean mixture
b. excessively atomized fuel
c. an excessively rich mixture

A

a.

81
Q
  1. Reduced air density at high altitude has a decided effect on carburetion, resulting in a reduction of engine power by

a. excessively enriching the fuel/air mixture
b. excessively leaning the fuel/air mixture
c. reducing fuel vaporization

A

a.

82
Q
  1. Which of the following conditions would most likely lead to detonation?

a. Late ignition timing
b. Use of fuel with too high an octane rating
c. Use of fuel with too low an octane rating

A

c.

83
Q
  1. How many of the following are factors in establishing the maximum compression ratio limitations of an aircraft engine?
    (1) Detonation characteristics of the fuel used
    (2) Design limitations of the engine
    (3) Degree of supercharging
    (4) Spark plug reach

a. Four
b. Two
c. Three

A

c.

84
Q
  1. Cam-ground pistons are installed in some aircraft engines to

a. provide a better fit at operating temperatures
b. act as a compensating feature so that a compensated magneto is not required
c. equalize the wear on all pistons

A

a.

85
Q
  1. What is an advantage of using metallic-sodium filled exhaust valves in aircraft reciprocating engines?

a. Increased strength and resistance to cracking
b. Reduced valve operating temperatures
c. Greater resistance to deterioration at high valve temperatures

A

b.

86
Q
  1. The operating temperature valve clearance of a radial engine as compared to cold valve clearance is

a. greater
b. less
c. the same

A

a.

87
Q
  1. When cleaning aluminum and magnesium engine parts, it is inadvisable to soak them in solutions containing soap because

a. some of the soap will become impregnated in the surface of the material and subsequently cause engine oil contamination and foaming
b. the soap can chemically alter the metals causing them to become more susceptible to corrosion
c. the parts can be destroyed by dissimilar metal electrolytic action if they are placed together in the solution for more than a few minutes

A

a.

88
Q
  1. Using the following information, determine how many degrees the crankshaft will rotate with both the intake and exhaust valves seated.
    Intake opens 15 degrees BTDC
    Exhaust opens 700 degrees BBDC
    Intake closes 45 degrees ABDC
    Exhaust closes 10 degrees ATDC

a. 290 degrees
b. 245 degrees
c. 25 degrees

A

b.

89
Q
  1. What tool is generally used to measure the crankshaft rotation in degrees?

a. Dial indicator
b. Timing disk
c. Prop Protractor

A

b..

90
Q
  1. How is proper end-gap clearance on new piston rings assured during the overhaul of an engine?

a. By accurately measuring and matching the outside diameter of the rings with the inside diameter of the cylinders.
b. By using rings specified by the engine manufacturer.
c. By placing the rings in the cylinder and measuring the end-gap with a feeler gauge.

A

c.

91
Q
  1. An aircraft reciprocating engine using hydraulic valve lifters is observed to have no clearance in its valve-operating mechanism after the minimum inlet oil and cylinder head temperatures for takeoff have been reached. When can this condition be expected?

a. During normal operation
b. When the lifters become deflated
c. As a result of carbon and sludge becoming trapped in the lifter and restricting its motion

A

a.

92
Q
  1. Compression ratio is the ratio between the

a. piston travel on the compression stroke and on the intake stroke
b. combustion chamber pressure on the combustion stroke and on the exhaust stroke
c. cylinder volume with piston at bottom dead center and at top dead center

A

c.

93
Q
  1. If fuel/air ratio is proper and ignition timing is correct, the combustion process should be completed

a. 20 to 300 before top center at the end of the compression stroke
b. when the exhaust valve opens at the end of the power stroke
c. just after top center at the beginning of the power stroke

A

c.

94
Q
  1. If an engine operates with a low oil pressure and a high oil temperature, the problem may be caused by a

a. leaking oil dilution valve
b. sheared oil pump shaft
c. clogged oil cooler annular jacket

A

a.

95
Q
  1. What is likely to occur if a reciprocating engine is operated at high power settings before it is properly warmed up?

a. Oil starvation of bearings and other parts
b. Excessively thinning of the engine oil
c. Accelerated oil breakdown and oxidation

A

a.

96
Q
  1. What is the basic operational sequence for reducing the power output of an engine equipped with a constant-speed propeller?

a. Reduce the RPM, then the manifold pressure.
b. Reduce the manifold pressure, then retard the throttle to obtain the correct RPM.
c. Reduce the manifold pressure, then the RPM.

A

c.

97
Q
  1. Which of the following will be caused by excessive valve clearance of a cylinder on a reciprocating aircraft engine?

a. Reduced valve overlap period
b. Intake and exhaust valves will open early and close late
c. A power increase by shortening the exhaust vent

A

a.

98
Q
  1. If the intake valve is opened too early in the cycle of operation of a four-stroke cycle engine, it may result in

a. improper scavenging of exhaust gases
b. engine kickback
c. backfiring into the induction system

A

c.

99
Q
  1. (1) Preignition is caused by improper ignition timing.
    (2) Detonation occurs when an area of the combustion chamber becomes incandescent and ignites the fuel/air mixture in advance of normal timed ignition.
    Regarding the above statements,

a. only No. 1 is true
b. both No. 1 and No. 2 are true.
c. neither No. 1 nor No. 2 is true

A

c.

100
Q
  1. If an engine cylinder is to be removed, at what position in the cylinder should the piston be?

a. Bottom dead center
b. Top dead center
c. Halfway between top and bottom dead center

A

b. (imagine)

101
Q
  1. During overhaul, reciprocating engine exhaust valves are checked for stretch

a. with a suitable inside spring caliper
b. with a contour or radius gauge
c. by placing the valve on a surface plate and measuring its length with a vernier height gauge

A

b.

102
Q
  1. The actual power delivered to the propeller of an aircraft engine is called

a. friction horsepower
b. brake horsepower
c. indicated horsepower

A

b.

103
Q
  1. If an engine with a stroke of 6 inches is operated at 2,000 RPM, the piston movement within the cylinder will be

a. at maximum velocity around TDC
b. constant during the entire 360 degrees of crankshaft travel
c. at maximum velocity 90 degrees after TDC

A

c.

104
Q
  1. If the oil pressure gauge fluctuates over a wide range from zero to normal operating pressure, the most likely cause is

a. low oil supply
b. broken or weak pressure relief valve spring
c. air lock in the scavenge pump intake

A

a.

105
Q
  1. What is the purpose of the safety circlet installed on some valve stems?

a. To hold the valve guide in position
b. To hold the valve spring retaining washer in position
c. To prevent valves from falling into the combustion chamber

A

c.

106
Q
  1. If the oil pressure of a cold engine is higher than at normal operating temperatures, the

a. oil system relief valve should be readjusted
b. engines lubrication system is probably operating normally
c. oil dilution system should be turned on immediately

A

b.

107
Q
  1. (1) Cast iron piston rings may be used in chrome-plated cylinders.
    (2) Chrome-plated rings may be used in plain steel cylinders.
    Regarding the above statements,

a. only No. 1 is true
b. neither No. 1 nor No. 2 is true
c. both No. 1 and No. 2 are true

A

c.

A/C Maintenance (17 decks)

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