Assessment Test


1. Worn main bearings in a diesel engine can result in __________.


2. A pyrometer is an instrument commonly used to measure __________.


3. During the power stroke of a four-stroke/cycle diesel engine, most of the side thrust of a trunk-type piston is absorbed by the __________.


4. Low compression pressure in a diesel engine is caused by __________.


5. Thermocouple pyrometers are used on large, main propulsion diesel engines to indicate the temperature of the __________.


6. A connecting rod in a four-stroke/cycle diesel engine is subject to __________.


7. Low compression pressure in a diesel engine may be the result of __________.


8. For a diesel engine, individual cylinder performance is commonly determined by exhaust gas __________.


9. In a four-stroke/cycle diesel engine, the intake valves open __________.


10. Low compression in a diesel engine can be caused by __________.


11. Pyrometers commonly found on diesel engine exhaust systems, consist of __________.


12. Which of the general advantages listed does the electrical pyrometer have over the mechanical pyrometer?


13. Which of the diesel engine exhaust mufflers listed is usually equipped with a spark arrestor?


14. When the cold valve lash is less than that specified by the manufacturer, diesel engine valves operating at normal temperatures will __________.


15. When the cold valve lash is less than that specified by the manufacturer, diesel engine valves operating at normal temperatures will __________.


16. A dry-type spark arrestor removes sparks from a diesel engine exhaust by __________.


17. If the valve lash on a diesel engine is set improperly, which of the following statements represents the most serious problem that can develop?


18. A drop in compression pressure in one cylinder of a diesel engine can be caused by __________.


19. If you increase the clearance between a valve stem and rocker arm, which of the listed conditions will occur?


20. Which of the devices is commonly used in measuring the clearances between the main engine bearings and the crankshaft?


21. To determine the main bearing clearances in a small auxiliary diesel engine, you should use __________.


22. Which of the following statements is true concerning the cetane number of diesel fuel?


23. The insertion of shims between the foot of a marine type connecting rod and a bearing box would result in __________.


24. Which of the following operating conditions will occur when shims are removed from the joint between the foot of a marine type diesel engine connecting rod and the bearing box? a. Decreased compression ratio


25. Worn main bearings will cause the compression ratio of a diesel engine to __________.


26. A mixture of 45% cetane and 55% alpha-methylnaphthalene is found to have the same ignition delay as a sample of diesel oil. The sample can be described as having a/an __________.


27. In a large, low-speed diesel engine the clearance between the piston crown and cylinder head is found to be excessive. In order to correct for this, you should __________.


28. An acceptable method for measuring the applied rotational force when tightening connecting rod and main bearing bolts, is to use a __________.


29. Which of the following relationships exist between the temperature developed in a combustion space, and the compression ratio of the engine?


30. Injection lag in a diesel engine may be caused by __________.


31. Abnormal crankpin bearing and piston skirt surface wear indicate __________.


32. Diesel engine injection lag is caused by __________.


33. Fuel oil injected into the cylinder of a diesel engine just after the piston passes top dead center, will __________.


34. Diesel engine crankshaft deflection readings are generally taken at four crank positions. Good engineering practice requires the deflection gage or indicator to be __________.


35. Heat for igniting the fuel oil in the cylinder of a diesel engine is generated by the __________.


36. One method of determining crankshaft misalignment is by __________.


37. In the cylinder of a diesel engine, fuel is ignited by the __________.


38. If there is a 'clicking' sound in the valve compartment of a diesel engine, the cause may be __________.


39. A loud clicking noise from the valve compartment of an operating diesel engine would indicate __________.


40. Excessively worn, or polished ends on a diesel engine valve spring, indicate __________.


41. When a hydraulic valve lifter is on the base circle of the cam, 'zero' valve lash is maintained by the __________.


42. Small cracks in the crankshaft bearing surface of a diesel engine are an indication of __________.


43. Which of the listed pumps discharges directly to the fuel oil settling tanks of a diesel engine main propulsion plant?


44. The depth of fuel oil in a tank is normally measured through the __________.


45. Standby, or emergency diesel generator day tanks should always be kept full to reduce the possibility of __________.


46. How can water enter the crankcase of an operating diesel engine?


47. Which of the listed contaminants will be satisfactorily removed from fuel oil by centrifuging?


48. Water accumulating in the crankcase of a diesel engine could indicate __________.


49. One engine manufacturer recommends heavy fuel oil should not be heated above 80°C to 95°C (176°F to 203°F) before purification. This upper limit should be observed to ensure against __________.


50. Excessive valve clearance will cause a valve to open __________.


51. The most effective method in removing water from diesel fuel oil is by __________.


52. In a four-stroke/cycle diesel engine, piston blow-by can result in increased __________.


53. Diesel engine piston ring blow-by is usually caused by excessive ring clearance at the ring __________.


54. During diesel engine warm-up, which type of valve lash adjuster compensates for the change in length of the exhaust valve stem?


55. Which of the bearings listed below is most widely used for the main and connecting rod bearings of a modern high-speed diesel engine?


56. For optimum results, centrifugal purification of heavy fuel oil should be accomplished with the fuel at the lowest practicable __________.


57. In a diesel engine, blow-by is generally the result of worn __________.


58. Heavy residual fuel oils are heated prior to centrifuging to __________.


59. One cause of diesel engine piston ring blow-by is __________.


60. Bearing clearances in small high-speed diesel engines should be measured with __________.


61. A centrifuge will satisfactorily remove which of the following contaminants from fuel oil:


62. If fuel oil were being discharged from the waste water outlet of a fuel oil disk type centrifuge operated as a separator, you should __________.


63. In a diesel engine, blow-by is a result of combustion gases leaking into the crankcase past the __________.


64. Diesel engine blow-by is the leakage of combustion gases past the __________.


65. In large, low-speed, main propulsion diesel engines, piston ring groove wear usually occurs at the __________.


66. A diesel engine cylinder head can crack as a result of __________.


67. The use of push rods becomes necessary in a diesel engine when __________.


68. The ring lands on a large, low-speed, main propulsion diesel engine piston may crack due to __________.


69. Which of the listed design features is found in an exhaust valve and not in an intake valve?


70. In an auxiliary diesel engine, one reason for knurling the piston skirt is to __________.


71. Many diesel engine exhaust valves are being constructed with hollow stems filled with sodium in order to __________.


72. In a diesel engine, which type of wrist pin uses bearings in the piston bosses, but is fixed to the small end of the connecting rod?


73. If clearance between a piston and the cylinder wall is excessive, piston slap will occur. The slap itself is caused by __________.


74. A built-up exhaust valve is one in which __________.


75. Brake specific fuel consumption is given in units of __________.


76. Which of the following statements concerning cylinder liner wear is true?


77. Valve rotators are commonly used on which of the listed diesel engine cylinder head valves?


78. To reduce the weight of the reciprocating parts, pistons of high-speed engines are made considerably shorter. This results in __________.


79. When comparing different fuels for different engines, the ignition quality of the fuel oil becomes a less critical consideration as __________.


80. Scuffed cylinder liner surfaces in a diesel engine can result from __________.


81. The adverse effects of burning high sulfur fuel can be compensated for by using a cylinder oil having sufficient __________.


82. A turbocharged, four-stroke/cycle diesel engine has a larger valve overlap than a naturally aspirated, four-stroke/cycle diesel engine in order to increase the __________.


83. Piston cooling fins are located __________.


84. If the oil scraper ring drain hole in a diesel engine piston becomes plugged, __________.


85. Many cast iron pistons are designed with heat dams, which serve to __________.


86. If the piston groove drain holes for the oil control rings become clogged, which of the following is likely to occur?


87. During the process of cylinder scavenging, the size of the exhaust valve opening is __________.


88. If the compression rings on a diesel engine piston become stuck in the ring groove, the cause may be due to __________.


89. Exhaust valve openings in a two-cycle diesel engine cylinder head are made as large as practical to __________.


90. Cold clearances between the skirt of an aluminum piston and the cylinder liner is about __________.


91. Improperly fitted piston rings in a diesel engine can result in __________.


92. Exhaust gases are generally removed from the cylinders of a two-stroke/cycle diesel engine by __________.


93. In the cylinder head of a two-stroke/cycle diesel engine, valves are used for __________.


94. Incomplete combustion in a running diesel engine can cause piston rings to become stuck as a result of __________.


95. One end of a diesel engine cylinder is sealed by the cylinder head and the other end by the __________.


96. A sudden drop in compression pressure in one cylinder of a diesel engine can be caused by __________.


97. The most common instrument used to measure diesel engine exhaust pressure is the __________.


98. When monitoring diesel engine performance, the most useful instrument to use is the __________.


99. In a two-stroke/cycle, opposed piston diesel engine, one crankshaft operates several crank angles in advance of the other crankshaft to __________.


100. The difference in crank lead between the upper and lower cranks of an opposed piston engine causes the lower crankshaft to __________.


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