Reciprocating Engines

Question 1

What is the purpose of dynamic dampers on crankshaft

Answer 1

Reduce engine vibration

Question 2

What types of bearings are generally found in reciprocating engines

Answer 2

Plain, Roller, Ball bearings

Question 3

Are the connecting rods used in each cylinder of a radial engine the same

Answer 3

NO… Radial engines use master and articulating rod assemblies

Question 4

Name the different types of piston rings

Answer 4

Oil control, Compression and oil Scrapper

Question 5

Where should piston rings gaps be installed relative to each other, and why

Answer 5

Compression ring gaps should be staggered so that they do not align. This prevents excessive blow-by

Question 6

What could result from incorrectly installed piston rings

Answer 6

Excessive oil consumption

Question 7

What purpose do oil control rings serve

Answer 7

They regulate the thickness of the oil film of the cylinder walls

Question 8

What is used to help prevent valve surge or floating in an aircraft engine

Answer 8

Two OR more springs are used on each valve

Question 9

On engines equipped with hydraulic valve lifters, what should the running valve clearance be

Answer 9

Zero

Question 10

What is the purpose of valve overlap

Answer 10

It allows better volumetric efficiency and lowers cylinder operating temperatures

Question 11

When troubleshooting a running engine malfunction, what does a cold cylinder indicate

Answer 11

No combustion in that cylinder

Question 12

Name at least one part of an inspection that should be made after a propeller strike (not sudden stoppage)

Answer 12

(1)Inspect the engine mounts, cranckcase, and nose section for damage
(2)Inspect the oil screens/filters for metal particles
(3) Inspect the propeller drive or crankshaft for misalignment.

Question 13

What is the fuel pressure range on Float-Type carburators

Answer 13

3 to 5 PSI

Question 14

What publication is used to check an engine for normal operation

Answer 14

The manufacturer’s maintenance manual

Question 15

What should be done to repair a loose stud in an engine crankcase

Answer 15

Remove the loose stud, inspect the hole for size and condition of the threads. It may be necessary to use a suitable oversize stud or HeliCoil insert

Question 16

What is an indication that a primer is leaking or is open
during engine operation

Answer 16

The engine will not idle properly

Question 17

What procedure should be followed when valve blow-by is indicated by a hissing sound on a reciprocating engine when pulling the propeller through

Answer 17

Perform a cylinder compression test to identify the faulty cylinder

Question 18

What factors about the condition of an engine can be learned by studying the results of a compression test

Answer 18

The results of a compression test determine if the valves, pistons rings and pistons are adequately sealing

Question 19

What is meant when it is said that an engine PART is within “serviceable limits”

Answer 19

A part that is within the manufacture’s serviceable limits and can be used in an engine, will not likely wear to the point
of causing engine failure within the next time between overhaul TBO interval

Question 20

When an engine is overhauled, how is its total time affected? When an engine is rebuilt, how is its operating history affected

Answer 20

OVERHAULED - The total time on the engine must be continued and the time since major overhaul is entered into the logbook.

REBUILT - If the manufacturer rebuilds the engine it is granted a ZERO-TIME status and is considered to have NO
previous operating history

Question 21

Name some of the precautions that should be performed prior engine replacement

Answer 21

Disconnect the battery, turn off the fuel valves, chock the wheels and if necessary install a tail stand

Question 22

When inspecting a piston, where are cracks most likely to be found

Answer 22

Highly stressed areas, base of piston bosses, inside at the junction of the bore and the walls and ring lands

Question 23

How is a cylinder barrel inspected for out of roundness

Answer 23

You must measure with a (cylinder bore gauge or a telescopic gauge and
micrometer,or an inside micrometer) the top of the cylinder and the skirt.
This two readings should be taken, 90° to each other

Question 24

Is the aircraft electrical system required to power a cylinder head temperature gauge

Answer 24

NO… A thermocouple is used as the electrical source

Question 25

What are the possible indications of an oil pressure transmitter or indicator malfunction

Answer 25

A severe or sudden drop in oil pressure while the oil temperature remains normal and the oil supply remains full

Question 26

What are some indications of induction system leakage

Answer 26

Low power and uneven running