124 Auto Engine Repair Copyright by Goodheart-Willcox Co., Inc. Inline V-type Opposed W-type Slant Figure 6-1. These are common cylinder arrangements used in automobiles. Inline and V-type are more common than opposed and W-type configurations. To become a professional engine technician, you must be able to differentiate between the various engine types. Understanding how an engine is designed and constructed will help you when troubleshooting problems. An experi- enced technician can usually glance into an engine com- partment and instantly describe numerous facts about how the engine is constructed and operates. For example, you might hear a technician say, “This is a dual overhead cam, four-cylinder engine with a direct ignition system and an intercooled turbocharger.” This information would help the technician if he or she had to work on the engine. This chapter introduces the many classifications and designs of modern engines. This information will prepare you for later chapters that discuss engine construction and service in more detail. In a sense, this chapter will help you develop the “language” of an engine technician so study carefully! Classifying Engines There are many ways to classify an engine, even though the fundamental engine parts are basically the same. These small design differences, however, can greatly affect engine performance and service. Modern auto- motive engines are normally classified by one or more of the following: • Arrangement of cylinders. • Number of cylinders. • Crankshaft design. • Cooling system type. • Type of fuel burned. • Type of ignition. • Fuel metering system. • Combustion chamber shape. • Cylinder head port design. • Number of valves per cylinder. • Valve location. • Camshaft location and driving mechanism. • Engine aspiration. • Method of balancing the engine. Cylinder Arrangement Cylinder arrangement refers to the position of the cyl- inders in the engine block in relation to the crankshaft. There are four common, basic cylinder arrangements found in cars and light trucks: inline, V-type, W-type, and opposed. Inline Engine An inline engine has cylinders positioned one after the other in a straight line. The cylinders are located vertically in a line parallel with the crankshaft centerline. This is shown in Figure 6-1. The cylinders are usually vertical, but they may be at an angle to vertical to reduce the height of the engine. Inline engines with cylinders that are angled to ver- tical are called slant engines. Inline engines are very common today. They are well suited to small-displacement (size) engines. Three-, four-, five-, and six-cylinder engines are frequently an inline design. Because of their small size and good fuel economy, inline four-cylinder engines are one of the most common types found in today’s cars. This design is found on domestic and import vehicles. An inline engine is a very durable and powerful design. Each crankshaft rod journal carries only one connecting rod. Therefore, inline 4- and 6-cylinder engines can produce very high horsepower-to-displacement power ratios without part failure. For this reason, many high performance tur- bocharged gas and diesel engines are inline configurations. V-Type Engine A V-type engine looks like the letter V when viewed from the front or rear, Figure 6-1. The two banks (sets) of cylinders lay at an angle from vertical on each side of the crankshaft. A V-type design reduces the length and height of the engine. This can allow an engine to fit into a small