Exhaust and Inlet Valves

   

1. The closing of the exhaust valves used on a modern, large, low-speed, main propulsion diesel engine may be directly provided by _____________./compressed air pressure

2. If the intake, or exhaust valve stem clearance is found to be excessive, in addition to too little movement of the  rocker arms, you should check for _____________./collapsed hydraulic valve lifters

3. A burned exhaust valve may be detected by a higher than  normal ____________./exhaust temperature from a particular cylinder

4. Which of the listed conditions will occur if a diesel engine exhaust valve is leaking?/All of the above

5. In a diesel engine, a leaking exhaust valve can cause  _____________./misfiring

6. Exhaust valve grooving and corrosion is caused by certain components of residual fuel oil. These components are  sodium, sulfur, and _____________./vanadium

7. The easiest way to locate a defective diesel engine exhaust valves is by _____________./comparing exhaust pyrometer readings

8. Increasing the exhaust valve tappet clearance of a diesel engine will result in the exhaust valve opening __________./later and closing earlier

9. Diesel engine exhaust valve springs are under compression when they are __________./in any position

10. A diesel engine exhaust valve spring is under compression when _____________./all of the above

11. The intake and exhaust valves used in a diesel engine are returned to their seats by _____________./spring force

12. In which of the scavenging methods listed will the exhaust valve be located in the cylinder head?/Uniflow

13. The purpose of an interference angle in a diesel engine exhaust valve is to ________.  I. work in conjunction with valve rotators to rotate   the valve  II. break up seat deposits/II only

14. The purpose of an interference angle in a diesel engine exhaust valve is to ________. I. break up seat deposits  II. work in conjunction with valve rotators to rotate   the valve/I only

15. The exhaust valve opens before bottom dead center in a four stroke engine to___________.  I. allow for blow down  II. reduce pumping losses/both I and II

16. The purpose of an interference angle in a diesel engine exhaust valve is to ________.  I. seat the valve quickly  II. break up seat deposits/both I and II

17. The purpose of an interference angle in a diesel engine exhaust valve is to ________.  I. work in conjunction with valve rotators to rotate   the valve  II. seat the valve quickly/II only

18. In a diesel engine, exhaust valves open before the intake ports are uncovered to ___________.  I. reduce pumping losses  II. reduce back pressure/both I and II

19. A substance found in residual fuels which tends to cause exhaust valve corrosion and grooving, is ____________./vanadium

20. During diesel engine warm-up, which type of valve lash  adjuster listed allows for the change in length of the  exhaust valves?/Hydraulic

21. Which of the listed design features is found in an exhaust valve and NOT in an intake valve?/Hard alloy steel construction

 

22. Many diesel engine exhaust valves are being constructed with hollow stems filled with sodium in order to _____________./assist in dissipating heat due to the extreme operating  temperatures

23. A built-up exhaust valve is one in which _____________./the stem and heads are made of different material

24. The size of the exhaust valve opening is ____________./most critical in a two-stroke/cycle diesel engine

25. Exhaust valve openings in a diesel engine cylinder head are made as large as practical to _____________./reduce the pumping loss associated with scavenging

26. The satisfactory operation of diesel engine exhaust valves usually depends on ______________./correct timing and proper seating

27. Decreasing the exhaust valve clearance of a diesel engine will cause the exhaust valve to open ______________./earlier and remain open longer

28. Multiple concentric valve springs are often used with diesel engine valves to ____________./operate the valve gear where a larger force is normally  required, but space limitations restrict the use of a single large spring

29. If the valve tappets in a diesel engine are set at greater clearances than those specified by the engine manufacturer, those valves will _____________./open late and close early

30. Increasing the valve clearance between a valve stem and  rocker arm, will result in the valve _____________./staying open for a shorter period of time

31. Which of the listed items should be secured before   performing any maintenance on a solenoid operated air start valve?/Electric power

32. An important design characteristic of an explosion relief valve for a diesel engine is the ability to _________./close quickly in order to prevent an inrush of air

33. Which statement regarding the arrangement and location of explosion relief valves used on an internal combustion  engines is true_____________?/Minimizing the danger from emission of flame is a key  consideration

34. Collapsed hydraulic valve lifters in a diesel engine will result in ____________./excessive valve clearance

35. At what pressure should a cylinder relief valve of an  internal combustion engine be set to relieve?/The device should be set to relieve at a pressure not more than 40 percent in excess of the maximum firing pressure.

36. The diesel engine valve subjected to most severe conditions of service is the ____________./cylinder exhaust valve

37. When the cold tappet clearance is less than that specified by the engine manufacturer, the diesel engine valves will _____________./open earlier than normal

38. In diesel engines, hydraulic valve lifters are used to  ____________./reduce valve gear pounding

39. Valve lash, or clearance refers to the _____________./clearance between the top of the valve stem and the rocker arm

40. What is the purpose of a hydraulic valve lash adjuster?/Allows for constant contact between the valve stem and the rocker arm regardless of whether the engine is cold or warm.

41. Diesel engine valve springs function to _____________./close the valves

42. Valve cages are used on some large diesel engines to  _____________./facilitate valve removal for servicing

43. During warm-up the expansion of valve stems due to engine heat, is allowed for by the _____________./valve lash

44. In a diesel engine, the spring force required for proper valve operation is determined by _____________./cam contour

45. According to Coast Guard regulations, isolation valves used in keel cooler installations are permitted to be constructed of ____________./bronze

46. If a single cylinder relief valve on a diesel engine lifts frequently while the engine is running, the cause may be an _____________./incorrectly adjusted fuel injector

47. Diesel engine air start valve timing is controlled by  _____________./individual cams and valve gear

48. If there is a "clicking" sound in the valve compartment of a diesel engine, the cause may be _____________./excessive valve lash

49. Excessively worn, or polished ends on a diesel engine valve spring, indicate ________________./spring surge

50. Excessive valve clearance will cause a valve to open  _____________./late and close early

51. The valve stem expansion associated with engine warm-up is allowed for by the ____________./valve lash adjusters

52. Diesel engine air start system check valves are opened by _____________./starting air pressure

53. Excessive valve lash in an auxiliary diesel engine will  cause the valves to open _____________./later and close sooner

54. If the valve lash on a diesel engine is set improperly,  which of the following statements represents the most  serious problem that can develop?/Too little lash may prevent the valves from seating   properly.

55. If you increase the clearance between a valve stem and  rocker arm, which of the listed conditions will occur?/Valve will open later.

56. Reducing the clearance between a valve stem and rocker arm will result in the valve _____________./having a longer duration of opening

57. If you were inspecting the valve springs on an auxiliary diesel engine, your best indication of impending spring  failure would be _____________./cracks in the surface of the spring

58. If the relief valve on a diesel engine cylinder lifts, the cause could be due to _____________./liquid in the cylinder

59. Which of the listed items should be secured before   performing any maintenance on a solenoid operated air start valve?/Electric power and starting air

60. Bouncing of the valve gear in a diesel engine can be caused by _____________./spring surge

61. Spring surge in diesel engine valve springs can result in _____________./bouncing of the valve gear

62. If a clicking sound is being produced from within the valve compartment of a diesel engine, the cause may be __________./all of the above

63. The force exerted by a valve spring to close the diesel  engine valves, is proportional to _____________./spring compression