Reciprocating Engines

Question 1

What is the purpose of dynamic dampers on crankshafts?

Answer 1

They reduce engine vibration

Question 2

What types of bearings are generally found in reciprocating engines

Answer 2

Plain, ball and roller 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 ring 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 blow-by (Blow-by also caused by worn or bore compression rings)

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 more springs are used on each valve

Question 9

On engines equipped with hydraulic valve lifters, what should be 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?

Answer 12

1. Inspect the engine mounts, crankcase, 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 a float type carburetor?

Answer 13

3 to 5 psi

Question 14

What publication is used to check engine for normal operation?

Answer 14

The manufactures maintenance manual

Question 15

What should be done to repair a loose stud in an engine crank case?

Answer 15

Removed a loose stud, inspect the hole for size and condition of threads and it may be necessary to use a suitable oversize stud or Heli coil 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 study of the results of a compression test?

Answer 18

The results of the compression test determine if the valves, piston 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 manufactures serviceable limits and can be using an engine will not likely wear to the point of causing engine failure within the next time between overhaul or maintenance intervals.

Question 20

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

Answer 20

Overhauled - the total time of the engine must be continued and the time since major overhaul is entered into the logbook

Rebuilt - if the manufacture rebuilds the engine, it is granted zero time status and is considered to have no previous operating history

Question 21

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

Answer 21

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

Question 22

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

Answer 22

Highly stress areas, base of the piston bosses, inside at the junction of the bore in 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 shoulder in the skirt these two reading should be taking 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 play?

Answer 26

Low power and uneven running