Reciprocating Engines

Question 1

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

Answer 1

Perform a cylinder compression test to identify the faulty cylinder and component

Question 2

What is the running valve clearance on engines equipped with hydraulic lifters?

Answer 2

Zero

Question 3

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

Answer 3

Lack of combustion in that cylinder

Question 4

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

Answer 4

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

Question 5

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

Answer 5

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

Question 6

How is a cylinder barrel inspected for out of roundness?

Answer 6

A cylinder bore gauge, telescopic gauge and micrometer, or an inside micrometer. Two readings are needed and should be taken 90 degrees to each other.

Question 7

What types of connecting rods are commonly found in radial engines?

Answer 7

Master and articulating rods.

Question 8

What are the different types of piston rings?

Answer 8

Compression, oil control, and oil scraper.

Question 8

What is the purpose of oil control rings?

Answer 8

Oil control rings regulate the amount of oil film on the cylinder walls.

Question 9

What types of bearings are in general use in reciprocating engines?

Answer 9

Plain, ball, and roller.

Question 10

How are piston ring gaps installed relative to each other on a piston, and why?

Answer 10

Compression ring gaps should be installed in a staggered position around the piston in order to prevent excessive blow-by.

Question 11

What is the purpose of crankshaft dynamic dampers?

Answer 11

To reduce engine vibration

Question 12

What is the purpose of valve overlap?

Answer 12

It permits better volumetric efficiency and lowers the cylinder operating temperature.

Question 13

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

Answer 13

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

Question 13

What may be the result of incorrect installation of piston rings?

Answer 13

Excessive oil consumption

Question 14

What is meant when it is said that an engine part is within serviceable limits?

Answer 14

A part that is within serviceable limits will not likely wear to the point of causing engine failure within the next time between overhaul interval.

Question 14

What is used in an aircraft engine to help prevent valve surge or float from occurring?

Answer 14

Two or more springs on each valve.

Question 14

What are some indications of induction system leakage?

Answer 14

Low power and uneven running

Question 14

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

Answer 14

The engine will not idle properly.

Question 15

When an engine is rebuilt by the manufacturer, how is its operating history affected?

Answer 15

A rebuilt engine is considered to have no previous operating history and can therefore be issued a zero-time record.