16. Figure 29–5 A dry sleeve is supported by the surrounding cylinder block. A wet sleeve must be thicker to be able to withstand combustion pressures without total support from the block.
17. Compacted graphite iron ( CGI ) has increased strength, ductility, toughness, and stiffness as compared to gray iron. If no magnesium is added, the iron will form gray iron when cooled, with the graphite present in flake form. If a very small amount of magnesium is added, the shape of the graphite begins to change to compacted graphite forms. Compacted graphite iron is used for bedplates and many diesel engine blocks. Its enhanced strength has been shown to permit reduced weight while still reducing noise vibration and harshness. What is Compacted Graphite Iron?
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25. Figure 29–10 Typical oil gallery plugs on the rear of a Chevrolet small-block V-8 engine.
26. The abbreviation LHD means left-hand dipstick , which is commonly used by rebuilders and remanufacturers in their literature describing Chevrolet small-block V-8 engines. Before about 1980, most small-block Chevrolet V-8s used an oil dipstick pad on the left side (driver’s side) of the engine block. Starting in about 1980, when oxygen sensors were first used on this engine, the dipstick was relocated to the right side of the block. Therefore, to be assured of ordering or delivering the correct engine, knowing the dipstick location is critical. An LHD block cannot be used with the exhaust manifold setup that includes the oxygen sensor without major refitting or the installing of a different style of oil pan that includes a provision for an oil dipstick. Engine blocks with the dipstick pad cast on the right side are, therefore, coded as right-hand dipstick (RHD) engines. What Does LHD Mean?
27. NOTE: Some blocks cast around the year 1980 are cast with both right- and left-hand oil dipstick pads, but only one is drilled for the dipstick tube. Figure 29–11 Small-block Chevrolet block. Note the left-hand dipstick hole and a pad cast for a right-hand dipstick.
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33. Figure 29–15 The main bearing bores of a warped block usually bend into a bowed shape. The greatest distortion is in the center bores. Original stress in the block casting is gradually relieved as the block is used. Slight warpage may occur as stress is relieved. In addition, the continued pounding caused by combustion will usually cause some stretch in the main bearing caps. Continued
34. Figure 29–16 When the main bearing caps bow downward, they also pinch in at the parting line. The main bearing bores gradually bow from the cylinder head and elongate vertically. This means that the bearing bore becomes smaller at the center line as the block distorts, pinching the bore inward at the sides. Continued
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38. Figure 29–18 (a) Checking the flatness of the block deck surface using a straightedge and a feeler gauge. (b) To be sure that the top of the block is flat, check the block in six locations as shown. ( a ) ( b ) Continued
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43. An easy way to calculate oversize piston size is to determine the amount of taper, double it, and add 0.010 inch (Taper x 2 + 0.010 in. = OS piston). Common oversize measurements include 0.020 inch, 0.030 inch, 0.040 inch, and 0.060 inch. Use caution when boring for an oversize measurement larger than 0.030 inch. How Can I Determine What Oversize Bore is Needed? HINT: The pistons that will be used should always be in hand before the cylinders are rebored. The cylinders are then bored and honed to match the exact size of the pistons.
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48. Figure 29–24 An assortment of ball-type deglazing hones. This type of hone does not straighten wavy cylinder walls. Continued
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58. Lifter bores in a block can be out-of-square with the camshaft, resulting in premature camshaft wear and variations in the valve timing from cylinder to cylinder. To correct for this variation, the lifter bores are bored and reamed oversize using a fixture fastened to the block deck to ensure proper alignment. Bronze lifter bushings are then installed and finish honed to achieve the correct lifter-to-bore clearance. Install Lifter Bore Bushings
65. Figure 29–35 A ground surface on one of the crankshaft cheeks next to a main bearing supports thrust loads on the crank.
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80. Continued Figure 29–39 The firing impulses of this odd-fire V-6 are unequally spaced because two cylinders share a common crankpin.
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84. To reduce side loads, some vehicle manufacturers offset the crankshaft from center. For example, if an engine rotates clockwise as viewed from the front, the crankshaft may be offset to the left to reduce the angle of the connecting rod during the power stroke. The offset usually varies from 1/16 inch to 1/2 inch, depending on make and model. Most gasoline engines used in hybrid gasoline/electric vehicles use an offset crankshaft. What is an Offset Crankshaft?
85. Figure 29–42 The crank throw is halfway down on the power stroke. The piston on the left without an offset crankshaft has a sharper angle than the engine on the right with an offset crankshaft.
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87. Figure 29–43 A crankshaft broken as a result of using the wrong torsional vibration damper. HINT: Push on the rubber (elastomer sleeve) of the vibration damper with fingers or pencil. If rubber does not spring back, replace the damper .
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93. Figure 29–47 Crankshaft sawed in half, showing drilled oil passages between the main and rod bearing journals. Continued
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97. HINT: If your fingernail catches on a groove when rubbed across a bearing journal, the journal is too rough to reuse and must be reground. Another test is to rub a copper penny across the journal. If any copper remains on the crankshaft, it must be reground.
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108. Figure 29–56 The two halves of a plain bearing meet at the parting faces. Figure 29–57 Bearing manufacturers refer to this bearing wall shape as an eccentric wall.
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117. Figure 29–66 Typical results of oil pressure loss; (a) extreme wear of the connecting rod journal, (b) overheating finally leading to failure of the bearing. Continued
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124. Figure 29–68 Typical bearing shell types found in modern engines: (a) half-shell thrust bearing, (b) upper main bearing insert, (c) lower main bearing insert, (d) full round-type camshaft bearing. (c) (d) (a) (b) Continued
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127. Figure 29–70 Many bearings are manufactured with a groove down the middle to improve the oil flow around the main journal.
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137. All engine parts should be stored in a safe location to help avoid damage prior to being installed in an engine. All camshafts and crankshafts should be stored vertically to avoid causing bending or warpage of these parts that could cause difficulty when the engine is being assembled. Do No Harm Figure 29–78 Crankshafts should be stored vertically to prevent possible damage or warpage. This clever bench-mounted tray for crankshafts not only provides a safe place to store crankshafts but it is out-of-the-way and cannot be accidentally tipped.
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