1 Reciprocating Engines

Question 1

1. What is the purpose of dynamic dampers on crankshafts?

Answer 1

They reduce engine vibration.

Question 2

2. What types of bearings are generally found in reciprocating engines?

Answer 2

Plain, ball, and roller bearings.

Question 3

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

4. Name the different types of piston rings.

Answer 4

Oil control, compression, and oil scraper.

Question 5

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 don’t align. This prevents excessive blow-by.

Question 6

6. What could result from incorrectly installed piston rings?

Answer 6

Excessive oil consumption.

Question 7

7. What purpose do oil control rings serve?

Answer 7

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

Question 8

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

Answer 8

2 or more springs are used on each valve.

Question 9

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

Answer 9

Zero.

Question 10

10. What is the purpose of valve overlap?

Answer 10

It allows better volumetric efficiency and lowers cylinder operating temps.