LO 8-2 Identify major cylinder block components and basic cylinder arrangements

Fundamentals of Cylinder Blocks

The cylinder block can be described as the largest single part and backbone of the diesel engine. Its primary function is to enclose cylinder components and liners (if equipped) as well as major engine components such as the crankshaft and camshaft Figure 5. Main bearing caps, which are part of the block, hold the crankshaft in position along the crankshaft centerline Figure 6.

FIGURE 08-5: This engine uses replaceable cylinder liners, enabling it to be quickly rebuilt and restored to original specifications.

FIGURE 08-6: Main bearing caps hold the crankshaft in position along the cylinder block’s main bearing bore.

The transmission, cylinder head(s), flywheel housing, and all other major engine parts are bolted or connected to the cylinder block Figure 7. The cylinders in diesel engine blocks are arranged in-line, V-banked, or horizontally opposed Figure 8. The number of cylinders within a block are commonly configured in even numbers of 4-, 5-, 6-, 8-, and even 10- and 12-cylinder bores; however, many single, 2-, 3-, and even 5-cylinder blocks are produced as well. High cylinder pressures combined with a rapid combustion phase create powerful mechanical forces that vibrate and torsionally twist the block and crankshaft. Furthermore, high cylinder pressures and both tension and compression loading of connecting rods distort the crankshaft main bearing and the connecting rod bores. These operating characteristics of diesels require specialized features to reduce noise, vibration, and unpleasant operating harshness. Strong, rigid, vibration-free, lightweight, and durable designs are necessary for engines to perform well under all operating conditions. Because the reciprocating action of pistons within the cylinder bores can eventually wear out the engine, blocks are often constructed with replaceable cylinder liners to restore engines to their original specifications.

FIGURE 08-7: The flywheel housing on this engine also encloses the rear-mounted geartrain.

FIGURE 08-8: Engine block cylinder banks are configured in one of at least three basic ways: A. in-line, B. V-bank, or C. horizontally opposed.