Halderman ch023 lecture

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  • Figure 23-1 Oil molecules cling to metal surfaces but easily slide against each other.
  • Figure 23-2 Wedge-shaped oil film developed below a moving block.
  • Figure 23-3 Wedge-shaped oil film curved around a bearing journal.
  • Figure 23-4 The dash oil pressure gauge may be a good indicator of engine oil pressure. If there is any concern about the oil pressure, always use a mechanical gauge to be sure.
  • Figure 23-5 An oil pump driven by the camshaft.
  • Figure 23-6 In an external gear-type oil pump, the oil flows through the pump around the outside of each gear. This is an example of a positive displacement pump, wherein everything entering the pump must leave the pump.
  • Figure 23-7 A typical internal/external oil pump mounted in the front cover of the engine that is driven by the crankshaft.
  • Figure 23-8 The operation of a rotor-type oil pump.
  • Figure 23-9 Gerotor-type oil pump driven by the crankshaft.
  • Figure 23-10 Oil pressure relief valves are spring loaded. The stronger the spring tension, the higher the oil pressure.
  • Figure 23-11 A typical engine design that uses both pressure and splash lubrication. Oil travels under pressure through the galleries (passages) to reach the top of the engine. Other parts are lubricated as the oil flows back down into the oil pan or is splashed onto parts.
  • Figure 23-12 (a) A visual inspection indicated that this pump cover was worn.
  • Figure 23-12 (b) An embedded particle of something was found on one of the gears, making this pump worthless except for scrap metal.
  • Figure 23-13 (a) The oil pump is the only part in an engine that gets unfiltered engine oil. The oil is drawn up from the bottom of the oil pan and is pressurized before flowing to the oil filter.
  • Figure 23-13 (b) If debris gets into an oil pump, the drive or distributor shaft can twist and/or break. When this occurs, the engine will lose all oil pressure.
  • Figure 23-14 An intermediate shaft drives the oil pump on this overhead camshaft engine. Note the main gallery and other drilled passages in the block and cylinder head.
  • Figure 23-15 Oil is sent to the rocker arms on this Chevrolet V-8 engine through the hollow pushrods. The oil returns to the oil pan through the oil drainback holes in the cylinder head.
  • Figure 23-16 A typical oil pan with a built-in windage tray used to keep oil from being churned up by the rotating crankshaft.
  • Figure 23-17 A dry sump system as used in a Chevrolet Corvette.
  • Figure 23-18 Oil is cooled by the flow of coolant through the oil filter adapter.
  • Halderman ch023 lecture

    1. 1. LUBRICATION SYSTEM OPERATION AND DIAGNOSIS 23
    2. 2. Objectives <ul><li>The student should be able to: </li></ul><ul><ul><li>Prepare for ASE Engine Repair (A1) certification test content area “D” (Lubrication and Cooling Systems Diagnosis and Repair). </li></ul></ul><ul><ul><li>Explain hydrodynamic lubrication. </li></ul></ul>
    3. 3. Objectives <ul><li>The student should be able to: </li></ul><ul><ul><li>Describe how the oil pump and engine lubrication work. </li></ul></ul><ul><ul><li>Discuss how oil flows to the valve train components. </li></ul></ul><ul><ul><li>Explain how to inspect an oil pump for wear. </li></ul></ul>
    4. 4. INTRODUCTION
    5. 5. Introduction <ul><li>Purpose of Lubrication System </li></ul><ul><ul><li>Lubricating all moving parts to prevent wear </li></ul></ul><ul><ul><li>Helping cool the engine </li></ul></ul>
    6. 6. Introduction <ul><li>Purpose of Lubrication System </li></ul><ul><ul><li>Helping seal piston rings </li></ul></ul><ul><ul><li>Cleaning and holding dirt in suspension </li></ul></ul>
    7. 7. Introduction <ul><li>Purpose of Lubrication System </li></ul><ul><ul><li>Neutralizing acids formed as the result of combustion </li></ul></ul><ul><ul><li>Reducing friction </li></ul></ul><ul><ul><li>Preventing rust and corrosion </li></ul></ul>
    8. 8. LUBRICATION PRINCIPLES
    9. 9. Lubrication Principles <ul><li>Purpose and Function </li></ul><ul><ul><li>Lubrication creates oil film to separate surfaces and support load </li></ul></ul>
    10. 10. Figure 23-1 Oil molecules cling to metal surfaces but easily slide against each other.
    11. 11. Lubrication Principles <ul><li>Purpose and Function </li></ul><ul><ul><li>Oil does not compress but may leak out between shaft and bearing </li></ul></ul><ul><ul><li>Under some conditions, oil keeps surfaces from seizing but some contact occurs </li></ul></ul><ul><ul><ul><li>Condition called boundary lubrication </li></ul></ul></ul>
    12. 12. Lubrication Principles <ul><li>Purpose and Function </li></ul><ul><ul><li>Viscosity and oil clearances help prevent boundary lubrication and wear </li></ul></ul><ul><ul><li>Boundary lubrication usually occurs under heavy load and at low speed </li></ul></ul>
    13. 13. Lubrication Principles <ul><li>Purpose and Function </li></ul><ul><ul><li>Lubrication occurs as wedge-shaped oil film builds between object and surface </li></ul></ul>
    14. 14. Figure 23-2 Wedge-shaped oil film developed below a moving block.
    15. 15. Lubrication Principles <ul><li>Hydrodynamic Lubrication </li></ul><ul><ul><li>Wedging action of lubricant called hydrodynamic lubrication </li></ul></ul><ul><ul><li>Depends on force applied to rate of speed between objects and thickness of oil </li></ul></ul>
    16. 16. Lubrication Principles <ul><li>Hydrodynamic Lubrication </li></ul><ul><ul><li>Thickness of oil is called viscosity </li></ul></ul><ul><ul><li>Viscosity is the ability of oil to resist flow </li></ul></ul><ul><ul><li>Prefix hydro- refers to liquids </li></ul></ul>
    17. 17. Lubrication Principles <ul><li>Hydrodynamic Lubrication </li></ul><ul><ul><li>Dynamic refers to moving materials </li></ul></ul><ul><ul><li>Hydrodynamic lubrication occurs when wedge-shaped film of oil develops between two surfaces that are moving </li></ul></ul>
    18. 18. Figure 23-3 Wedge-shaped oil film curved around a bearing journal.
    19. 19. Lubrication Principles <ul><li>Hydrodynamic Lubrication </li></ul><ul><ul><li>Engine oil pressure system feeds oil into the lighted loaded part of bearing oil clearance </li></ul></ul>
    20. 20. Lubrication Principles <ul><li>Hydrodynamic Lubrication </li></ul><ul><ul><li>Hydrodynamic lubrication takes over as shaft rotates in bearing to produce hydrodynamic oil film </li></ul></ul>
    21. 21. Lubrication Principles <ul><li>Hydrodynamic Lubrication </li></ul><ul><ul><li>Pressure between bearings and crankshaft can exceed 1,000 PSI (6,900 kPa) due to wedging action </li></ul></ul>
    22. 22. ENGINE LUBRICATION SYSTEMS
    23. 23. Engine Lubrication Systems <ul><li>Purpose and Function </li></ul><ul><ul><li>Primary purpose of lubrication system is to maintain continuous oil supply to bearings </li></ul></ul>
    24. 24. Engine Lubrication Systems <ul><li>Purpose and Function </li></ul><ul><ul><li>Oil pressure must be high enough to get oil to bearings with force needed for proper cooling </li></ul></ul>
    25. 25. Engine Lubrication Systems <ul><li>Normal Oil Pressure </li></ul><ul><ul><li>Normal engine oil pressure is from 10 to 60 PSI (200 to 400 kPa), or 10 PSI per 1000 engine RPM </li></ul></ul>
    26. 26. Engine Lubrication Systems <ul><li>Normal Oil Pressure </li></ul><ul><ul><li>Higher oil pressure occurs when engine is cold due to higher viscosity of cold oil </li></ul></ul><ul><ul><li>Lower oil pressure occurs when at normal operating temperature </li></ul></ul>
    27. 27. Engine Lubrication Systems <ul><li>Normal Oil Pressure </li></ul><ul><ul><li>Lower oil pressure at idle and higher pressure at higher engine speeds because oil pumps are “positive displacement” pumps </li></ul></ul>
    28. 28. Engine Lubrication Systems <ul><li>Normal Oil Pressure </li></ul><ul><ul><li>Oil pressure measurements show oil pump pressure, not pressure due to hydrodynamic forces </li></ul></ul>
    29. 29. Figure 23-4 The dash oil pressure gauge may be a good indicator of engine oil pressure. If there is any concern about the oil pressure, always use a mechanical gauge to be sure.
    30. 30. Engine Lubrication Systems <ul><li>Oil Temperature </li></ul><ul><ul><li>Excessive high or low temperatures are harmful to engine </li></ul></ul><ul><ul><li>Too cold and oil becomes too thick to flow and lubricate engine parts </li></ul></ul>
    31. 31. Engine Lubrication Systems <ul><li>Oil Temperature </li></ul><ul><ul><li>Too hot and oil becomes too thin to provide sufficient film strength </li></ul></ul><ul><ul><li>Estimated oil temperature </li></ul></ul><ul><ul><ul><li>Estimated oil temperature = Outside air temperature + 120°F </li></ul></ul></ul>
    32. 32. Engine Lubrication Systems <ul><li>Oil Temperature </li></ul><ul><ul><li>Oil temperature should not exceed 300°F (150°C) </li></ul></ul>
    33. 33. OIL PUMPS
    34. 34. Oil Pumps <ul><li>Purpose and Function </li></ul><ul><ul><li>Provide 3 to 6 gallons of oil per minute </li></ul></ul><ul><ul><li>Maintain pressure to force oil through lubrication system </li></ul></ul>
    35. 35. Oil Pumps <ul><li>Parts and Operation </li></ul><ul><ul><li>In most engines with distributor, distributor drive gear meshes with gear on camshaft </li></ul></ul>
    36. 36. Figure 23-5 An oil pump driven by the camshaft.
    37. 37. Oil Pumps <ul><li>Parts and Operation </li></ul><ul><ul><li>Oil pump is driven from end of distributor shaft </li></ul></ul><ul><ul><li>Distributor-driven oil pump turns pump at one-half engine speed </li></ul></ul>
    38. 38. Oil Pumps <ul><li>Parts and Operation </li></ul><ul><ul><li>On crankshaft-drive oil pump systems, oil pump turns at same speed as crankshaft </li></ul></ul>
    39. 39. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>All oil pumps are positive displacement pumps </li></ul></ul><ul><ul><li>Each rotation delivers same volume of oil </li></ul></ul><ul><ul><li>Delivers oil at higher pressure as speed of pump increases </li></ul></ul>
    40. 40. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>Two types of oil pumps: gear or rotor </li></ul></ul><ul><ul><li>External gear type </li></ul></ul><ul><ul><ul><li>Usually driven by shaft from distributor </li></ul></ul></ul>
    41. 41. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>External gear type </li></ul></ul><ul><ul><ul><li>Rotates at half crankshaft speed </li></ul></ul></ul><ul><ul><ul><li>Consists of two spur gears—one gear is driven while one is idle </li></ul></ul></ul>
    42. 42. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>External gear type </li></ul></ul><ul><ul><ul><li>As gear teeth come out of mesh, they are filled by oil from pump inlet </li></ul></ul></ul>
    43. 43. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>External gear type </li></ul></ul><ul><ul><ul><li>When pump pumps, soil goes outside of each gear between gear teeth and housing </li></ul></ul></ul>
    44. 44. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>External gear type </li></ul></ul><ul><ul><ul><li>As teeth mesh, oil is forced into oil passage creating pressure </li></ul></ul></ul>
    45. 45. Figure 23-6 In an external gear-type oil pump, the oil flows through the pump around the outside of each gear. This is an example of a positive displacement pump, wherein everything entering the pump must leave the pump.
    46. 46. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>Internal/external gear type </li></ul></ul><ul><ul><ul><li>Driven by crankshaft and operates at engine speed </li></ul></ul></ul><ul><ul><ul><li>Two gears and crescent stationary element used </li></ul></ul></ul>
    47. 47. Figure 23-7 A typical internal/external oil pump mounted in the front cover of the engine that is driven by the crankshaft.
    48. 48. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>Rotor type </li></ul></ul><ul><ul><ul><li>Driven by crankshaft </li></ul></ul></ul><ul><ul><ul><li>Uses lobe-shape gear meshing with inside of lobed rotor </li></ul></ul></ul>
    49. 49. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>Rotor type </li></ul></ul><ul><ul><ul><li>Center lobed section is driven; outer section idles </li></ul></ul></ul><ul><ul><ul><li>As lobes separate, oil is drawn in </li></ul></ul></ul>
    50. 50. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>Rotor type </li></ul></ul><ul><ul><ul><li>As pump rotates, oil is carried between lobes </li></ul></ul></ul><ul><ul><ul><li>As lobes mesh, they force oil out from between them under pressure </li></ul></ul></ul>
    51. 51. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>Rotor type </li></ul></ul><ul><ul><ul><li>Pump maintains pressure of at least 10 PSI (70 kPa) when engine is hot and idling </li></ul></ul></ul>
    52. 52. Figure 23-8 The operation of a rotor-type oil pump.
    53. 53. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>Gerotor type </li></ul></ul><ul><ul><ul><li>Uses inner and outer rotor </li></ul></ul></ul><ul><ul><ul><li>Term derived from “generated rotor” </li></ul></ul></ul>
    54. 54. Oil Pumps <ul><li>Types of Oil Pumps </li></ul><ul><ul><li>Gerotor type </li></ul></ul><ul><ul><ul><li>Inner rotor has one fewer teeth than outer rotor </li></ul></ul></ul><ul><ul><ul><li>Both rotors rotate </li></ul></ul></ul>
    55. 55. Figure 23-9 Gerotor-type oil pump driven by the crankshaft.
    56. 56. Oil Pumps <ul><li>Oil Pressure Regulation </li></ul><ul><ul><li>Maximum pressure is limited with pressure relief valve </li></ul></ul><ul><ul><li>Relief valve sometimes called pressure regulating valve </li></ul></ul><ul><ul><li>Relief valve limits maximum pressure by bleeding oil to inlet side of pump </li></ul></ul>
    57. 57. Figure 23-10 Oil pressure relief valves are spring loaded. The stronger the spring tension, the higher the oil pressure.
    58. 58. Oil Pumps <ul><li>Oil Pressure Regulation </li></ul><ul><ul><li>Relief valve spring tension determines maximum oil pressure </li></ul></ul><ul><ul><li>Without relief valve, oil pressure increases as engine speed increases </li></ul></ul>
    59. 59. Oil Pumps <ul><li>Oil Pressure Regulation </li></ul><ul><ul><li>Oil pump large enough to provide pressure a low engine speeds </li></ul></ul><ul><ul><li>Oil pump small enough so it won’t cavitate at high speed </li></ul></ul>
    60. 60. Oil Pumps <ul><li>Oil Pressure Regulation </li></ul><ul><ul><li>Cavitation occurs when pump pulls oil faster than it can flow from pan to pickup </li></ul></ul><ul><ul><li>When pump cannot get enough oil, it pulls air </li></ul></ul>
    61. 61. Oil Pumps <ul><li>Oil Pressure Regulation </li></ul><ul><ul><li>NOTE: Sheet metal covers over pickup screen prevent cavitation. Oil under cover helps prevent pump from drawing air. </li></ul></ul><ul><ul><li>Oil from pump flows through oil filter and then to moving parts </li></ul></ul>
    62. 62. Figure 23-11 A typical engine design that uses both pressure and splash lubrication. Oil travels under pressure through the galleries (passages) to reach the top of the engine. Other parts are lubricated as the oil flows back down into the oil pan or is splashed onto parts.
    63. 63. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Leaks </li></ul></ul><ul><ul><ul><li>Leaks are clearances at end points of lubrication system </li></ul></ul></ul>
    64. 64. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Leaks </li></ul></ul><ul><ul><ul><li>These clearances are necessary for proper engine operation </li></ul></ul></ul>
    65. 65. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Leaks </li></ul></ul><ul><ul><ul><li>As parts wear, leaks become greater and oil pressure drops </li></ul></ul></ul>
    66. 66. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Oil pump capacity </li></ul></ul><ul><ul><ul><li>Oil pump must supply extra oil for leaks </li></ul></ul></ul>
    67. 67. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Oil pump capacity </li></ul></ul><ul><ul><ul><li>Capacity of oil pump determined by size, rotating speed, condition </li></ul></ul></ul>
    68. 68. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Oil pump capacity </li></ul></ul><ul><ul><ul><li>If leaks are greater than pump capacity, oil pressure is low </li></ul></ul></ul>
    69. 69. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Oil pump capacity </li></ul></ul><ul><ul><ul><li>Higher engine speed increases capacity of pump to force oil out of leaks </li></ul></ul></ul>
    70. 70. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Oil pump capacity </li></ul></ul><ul><ul><ul><li>NOTE: Clogged oil pump pickup screen can cause lower oil pressure. </li></ul></ul></ul>
    71. 71. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Viscosity of engine oil </li></ul></ul><ul><ul><ul><li>Viscosity affects pump capacity and leakage </li></ul></ul></ul>
    72. 72. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Viscosity of engine oil </li></ul></ul><ul><ul><ul><li>Oil with low viscosity slips past edges of pump and flows freely from leaks </li></ul></ul></ul>
    73. 73. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Viscosity of engine oil </li></ul></ul><ul><ul><ul><li>Hot oil has low viscosity so hot engine has lower oil pressure </li></ul></ul></ul>
    74. 74. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Viscosity of engine oil </li></ul></ul><ul><ul><ul><li>Cold oil is more viscous resulting in higher pressures </li></ul></ul></ul>
    75. 75. Oil Pumps <ul><li>Factors Affecting Oil Pressure </li></ul><ul><ul><li>Viscosity of engine oil </li></ul></ul><ul><ul><ul><li>Higher viscosity oil raises oil pressure to regulating setting of relief valve at a lower engine speed </li></ul></ul></ul>?
    76. 76. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>Cover is removed to check condition of oil pump </li></ul></ul><ul><ul><li>Visual inspection </li></ul></ul><ul><ul><ul><li>Inspect gears and housing for scoring </li></ul></ul></ul>
    77. 77. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>Visual inspection </li></ul></ul><ul><ul><ul><li>Replace pump if heavy scoring apparent </li></ul></ul></ul>
    78. 78. Figure 23-12 (a) A visual inspection indicated that this pump cover was worn.
    79. 79. Figure 23-12 (b) An embedded particle of something was found on one of the gears, making this pump worthless except for scrap metal.
    80. 80. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>Measurements </li></ul></ul><ul><ul><ul><li>If light scoring, measure pump clearances </li></ul></ul></ul><ul><ul><ul><li>Feeler gauge often used for measurements </li></ul></ul></ul>
    81. 81. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>Measurements </li></ul></ul><ul><ul><ul><li>Gauging plastic used to measure space between side of gears and cover </li></ul></ul></ul>
    82. 82. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>Measurements </li></ul></ul><ul><ul><ul><li>Replace if excessive clearance or scoring is found </li></ul></ul></ul>
    83. 83. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>NOTE: Oil pump is “garbage pit” of engine. Debris is often forced through the gears and housing. </li></ul></ul>
    84. 84. Figure 23-13 (a) The oil pump is the only part in an engine that gets unfiltered engine oil. The oil is drawn up from the bottom of the oil pan and is pressurized before flowing to the oil filter.
    85. 85. Figure 23-13 (b) If debris gets into an oil pump, the drive or distributor shaft can twist and/or break. When this occurs, the engine will lose all oil pressure.
    86. 86. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>Refer to manufacturer’s specifications when checking pump for wear </li></ul></ul><ul><ul><li>Typical pump clearances </li></ul></ul><ul><ul><ul><li>End plate clearance: 0.0015 in. (0.04 mm) </li></ul></ul></ul>
    87. 87. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>Typical pump clearances </li></ul></ul><ul><ul><ul><li>Side (rotor) clearance: 0.012 in. (0.30 mm) </li></ul></ul></ul>
    88. 88. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>Typical pump clearances </li></ul></ul><ul><ul><ul><li>Rotor tip clearance: 0.010 in. (0.25 mm) </li></ul></ul></ul>
    89. 89. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>Typical pump clearances </li></ul></ul><ul><ul><ul><li>Gear end play clearance: 0.004 in. (0.10 mm) </li></ul></ul></ul>
    90. 90. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>Check all parts </li></ul></ul><ul><ul><li>Check relief valve for scoring </li></ul></ul>
    91. 91. Oil Pumps <ul><li>Oil Pump Checks </li></ul><ul><ul><li>Check condition of relief valve spring </li></ul></ul><ul><ul><li>When installing oil pump, coat sealing surfaces with engine assembly lubricant </li></ul></ul>
    92. 92. OIL PASSAGES
    93. 93. Oil Passages <ul><li>Purpose and Function </li></ul><ul><ul><li>Oil from pump first flows through oil filter </li></ul></ul><ul><ul><li>Oil then flows through drilled hole to drilled main oil gallery </li></ul></ul><ul><ul><ul><li>Inline engines use one oil gallery </li></ul></ul></ul>
    94. 94. Oil Passages <ul><li>Purpose and Function </li></ul><ul><ul><li>Oil then flows through drilled hole to drilled main oil gallery </li></ul></ul><ul><ul><ul><li>V-type engines may use two or three galleries </li></ul></ul></ul>
    95. 95. Oil Passages <ul><li>Purpose and Function </li></ul><ul><ul><li>Passages drilled through block bulkheads allow oil to go from main oil gallery to main and cam bearings </li></ul></ul>
    96. 96. Figure 23-14 An intermediate shaft drives the oil pump on this overhead camshaft engine. Note the main gallery and other drilled passages in the block and cylinder head.
    97. 97. Oil Passages <ul><li>Purpose and Function </li></ul><ul><ul><li>In some engines, oil goes to cam bearings first, then to main bearings </li></ul></ul><ul><ul><li>Oil holes in bearings must match drilled passages </li></ul></ul>
    98. 98. Oil Passages <ul><li>Purpose and Function </li></ul><ul><ul><li>Over time, bearings wear </li></ul></ul><ul><ul><li>Excess clearance allows excess leakage around sides of bearings </li></ul></ul>
    99. 99. Oil Passages <ul><li>Purpose and Function </li></ul><ul><ul><li>Little or no oil may be left for bearings downstream in lubricating system </li></ul></ul><ul><ul><li>Bearing failure may result </li></ul></ul>
    100. 100. Oil Passages <ul><li>Valve Train Lubrication </li></ul><ul><ul><li>Oil gallery may intersect or have drilled passages to valve lifter bores </li></ul></ul><ul><ul><li>With hydraulic lifters, oil pressure in gallery keeps them lubricated </li></ul></ul>
    101. 101. Oil Passages <ul><li>Valve Train Lubrication </li></ul><ul><ul><li>On some engines, oil from lifters goes up center of hollow pushrod to lubricate pushrod ends, rocker arm pivot, and valve stem tip </li></ul></ul>
    102. 102. Oil Passages <ul><li>Valve Train Lubrication </li></ul><ul><ul><li>In other engines, drilled oil passage from gallery or cam bearings leads to head gasket hole and drilled hole to carry oil to rocker arm shaft </li></ul></ul><ul><ul><li>Some engines used enlarged bolt hold to rocker arm shaft </li></ul></ul>
    103. 103. Oil Passages <ul><li>Valve Train Lubrication </li></ul><ul><ul><li>Holes in bottom of rocker arm shaft allow lubrication of rocker arm pivot </li></ul></ul><ul><ul><li>Rocker arm assemblies need only surface coating of oil </li></ul></ul><ul><ul><ul><li>Restrictions or metered openings restrict oil flow </li></ul></ul></ul>
    104. 104. Oil Passages <ul><li>Valve Train Lubrication </li></ul><ul><ul><li>Oil from rocker assemblies returns to oil pan through drain holes </li></ul></ul><ul><ul><li>Oil drain holes often drain oil on camshaft or cam drive gears </li></ul></ul>
    105. 105. Figure 23-15 Oil is sent to the rocker arms on this Chevrolet V-8 engine through the hollow pushrods. The oil returns to the oil pan through the oil drainback holes in the cylinder head.
    106. 106. Oil Passages <ul><li>Valve Train Lubrication </li></ul><ul><ul><li>Some engines direct positive oil flow to cam drive gears or chain </li></ul></ul><ul><ul><ul><li>Nozzle </li></ul></ul></ul>
    107. 107. Oil Passages <ul><li>Valve Train Lubrication </li></ul><ul><ul><li>Some engines direct positive oil flow to cam drive gears or chain </li></ul></ul><ul><ul><ul><li>Chamfer on bearing parting surface </li></ul></ul></ul>
    108. 108. OIL PANS
    109. 109. Oil Pans <ul><li>Purpose and Function </li></ul><ul><ul><li>Oil pan, or sump, is where engine oil is used for lubricating engine </li></ul></ul><ul><ul><li>Pan baffles and oil pan shapes keep oil inlet under oil at all times </li></ul></ul>
    110. 110. Oil Pans <ul><li>Purpose and Function </li></ul><ul><ul><li>Crankshaft rotation can churn oil causing air bubbles in oil and foaming </li></ul></ul><ul><ul><li>Baffle or windage tray is sometimes used to eliminate oil churning </li></ul></ul>?
    111. 111. Figure 23-16 A typical oil pan with a built-in windage tray used to keep oil from being churned up by the rotating crankshaft.
    112. 112. DRY SUMP SYSTEM
    113. 113. Dry Sump System <ul><li>Construction and Operation </li></ul><ul><ul><li>Sump describes location where oil is stored </li></ul></ul><ul><ul><li>Most engines hold oil in oil pan; pump draws oil from bottom </li></ul></ul>
    114. 114. Dry Sump System <ul><li>Construction and Operation </li></ul><ul><ul><li>This system is called a wet sump oil system </li></ul></ul><ul><ul><li>Dry sump system uses shallow pan </li></ul></ul><ul><ul><ul><li>Oil is pumped into remote reservoir </li></ul></ul></ul>
    115. 115. Dry Sump System <ul><li>Construction and Operation </li></ul><ul><ul><li>Dry sump system uses shallow pan </li></ul></ul><ul><ul><ul><li>Oil is cooled and trapped air escapes </li></ul></ul></ul>
    116. 116. Dry Sump System <ul><li>Construction and Operation </li></ul><ul><ul><li>Dry sump system uses shallow pan </li></ul></ul><ul><ul><ul><li>Dry sump uses externally mounted oil reservoir </li></ul></ul></ul>
    117. 117. Dry Sump System <ul><li>Advantages </li></ul><ul><ul><li>Advantages of dry sump system </li></ul></ul><ul><ul><ul><li>Shallow pan allows engine to be mounted lower, improving cornering </li></ul></ul></ul>
    118. 118. Dry Sump System <ul><li>Advantages </li></ul><ul><ul><li>Advantages of dry sump system </li></ul></ul><ul><ul><ul><li>Oil capacity can be expanded because reservoir is not limited </li></ul></ul></ul>
    119. 119. Dry Sump System <ul><li>Advantages </li></ul><ul><ul><li>Advantages of dry sump system </li></ul></ul><ul><ul><ul><li>Vehicle can corner or brake for long periods </li></ul></ul></ul>
    120. 120. Dry Sump System <ul><li>Advantages </li></ul><ul><ul><li>Advantages of dry sump system </li></ul></ul><ul><ul><ul><li>Engine can develop more power because oil is kept away from crankshaft </li></ul></ul></ul>
    121. 121. Dry Sump System <ul><li>Disadvantages </li></ul><ul><ul><li>Disadvantages of dry sump system </li></ul></ul><ul><ul><ul><li>Expensive because it needs extra components and plumbing </li></ul></ul></ul>
    122. 122. Dry Sump System <ul><li>Disadvantages </li></ul><ul><ul><li>Disadvantages of dry sump system </li></ul></ul><ul><ul><ul><li>Complex because it creates more possibilities for oil leaks and changes routine maintenance </li></ul></ul></ul>
    123. 123. Figure 23-17 A dry sump system as used in a Chevrolet Corvette.
    124. 124. OIL COOLERS
    125. 125. Oil Coolers <ul><li>Larger capacity oil pan helps control oil temperature </li></ul><ul><li>Remote mounted oil coolers </li></ul><ul><ul><li>Warm oil in cold weather </li></ul></ul><ul><ul><li>Cool oil when engine is hot </li></ul></ul>
    126. 126. Oil Coolers <ul><li>Oil Temperature </li></ul><ul><ul><li>Above 212°F (100°C) </li></ul></ul><ul><ul><li>Below 280°F to 300°F (138°C to 148°C) </li></ul></ul>?
    127. 127. Figure 23-18 Oil is cooled by the flow of coolant through the oil filter adapter.
    128. 128. FREQUENTLY ASKED QUESTION <ul><li>Is a High-Pressure or High-Volume Oil Pump Needed? </li></ul><ul><ul><li>No. Engine parts need pressure after the oil reaches the parts that are to be lubricated. The oil film between the parts is developed and maintained by hydrodynamic lubrication. Excessive oil pressure requires more horsepower and provides no better lubrication than the minimum effective pressure. </li></ul></ul>? BACK TO PRESENTATION A high-volume pump is physically larger and pumps more oil with each revolution. A high-volume pump is used mostly in race engines where the main and rod bearing clearances are much greater than normal and therefore would need a great volume of oil to make up for the oil leaking from the wide clearances.
    129. 129. TECH TIP <ul><li>The New Hemi Engine Oiling System </li></ul><ul><ul><li>The Chrysler Hemi V-8 engine uses a unique oiling system because the valve lifters are fed oil from the top of the cylinder heads and through the pushrods. </li></ul></ul>BACK TO PRESENTATION While it is normal to have oil flowing through hollow pushrods, it is unique that in the Hemi V-8 the oil flows backward from normal and from the head down the hollow pushrods to the lifters. Be sure to use the specified viscosity of oil, as this is critical for proper lubrication of the valve lifters.
    130. 130. FREQUENTLY ASKED QUESTION <ul><li>Why Is It Called a Windage Tray? </li></ul><ul><ul><li>A windage tray is a plate or baffle installed under the crankshaft and is used to help prevent aeration of the oil. Where does the wind come from? Pistons push air down into the crankcase as they move from top dead center to bottom dead center. </li></ul></ul>? BACK TO PRESENTATION The pistons also draw air and oil upward when moving from bottom dead center to top dead center. At high engine speeds, this causes a great deal of airflow, which can easily aerate the oil. Therefore, a windage tray is used to help prevent this movement of air (wind) from affecting the oil in the pan. <ul><li>Try the following: </li></ul><ul><ul><li>Take an oil pan and add a few quarts (liters) of oil. </li></ul></ul><ul><ul><li>Then take an electric hair dryer and use it to blow air into the oil pan. </li></ul></ul><ul><li>Oil will be thrown everywhere, which helps illustrate why windage trays are used in all newer engines. </li></ul>
    131. 131. FREQUENTLY ASKED QUESTION <ul><li>What Is Acceptable Oil Consumption? </li></ul><ul><ul><li>There are a number of opinions regarding what is acceptable oil consumption. Most vehicle owners do not want their engine to use any oil between oil changes even if they do not change it more often than every 7,500 miles (12,000 km). Engineers have improved machining operations and piston ring designs to help eliminate oil consumption. </li></ul></ul>? BACK TO PRESENTATION <ul><li>Many stationary or industrial engines are not driven on the road, so they do not accumulate miles but still may consume excessive oil. </li></ul><ul><li>A general rule for “acceptable” oil consumption is that it should be about 0.002 to 0.004 pound per horsepower per hour. To figure, use the following: </li></ul><ul><ul><li>Operating hp × Total hours </li></ul></ul>Therefore, oil consumption is based on the amount of work an engine performs. Although the formula may not be viable for vehicle engines used for daily transportation, it may be for the marine or industrial engine builder. Generally, oil consumption that is greater than 1 quart for every 600 miles (1 liter per 1,000 km) is considered to be excessive with a motor vehicle.

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