The Types of Engine Blocksby Richard Rowe
The internal combustion engine takes many forms, and many efforts have been made to optimize the performance of every component from oil-pan to air-cleaner. The engine block itself is no exception, and of all the different designs experimented with over the years, the following are the most popular and prolific.
The V Engine
This is probably the most popular engine block on the market and comes in several iterations. From massive Cadillac V16s, to classic V8s to the tiny V4s used on motorcycles; the V engine has a long history and time-tested record of reliability. The primary advantage of a V engine is its compact nature. Because it uses a pair of cylinder banks running parallel to each other, a V-16 engine is almost the same length as an inline-eight and only a bit wider. The only downside of a V engine is smoothness, which can be quite bad due to the fact that the pistons are set at odd angles to the engine center-line. This effect can be offset by adding more cylinders, which is why luxury cars often have 10 cylinders or more.
Inline-block engines use a series of cylinders that run in a single line from the back of the engine to the front. Because these engines typically run smoothly, they are often used in applications that require high-rpm power, which makes the configuration ideally suited to the small-displacement engines used in most passenger cars. It is for this reason that almost all four-cylinder engines use an inline-block configuration. Additionally, an inline configuration by design lends itself to the usage of an overhead cam (OHC) cylinder head, which also helps to increase high-rpm horsepower. This inline-four/OHC cylinder head combination is used to good effect on practically all four-cylinder cars currently in production.
Boxer engines are used primarily by Porsche and Subaru and are some of the most highly developed engines around. The easiest way to understand the boxer engine is to think of it as a V engine that has been pressed flat, so that the cylinder heads are directly opposite each other. The boxer engine has a number of advantages. Because the pistons on one bank effectively serve as counterweight for the other side, the crankshaft does not require counterweights of its own. This makes for a shorter, lighter crankshaft and a higher revving and more powerful engine. Boxer engines are also relatively light and are low to the ground. This can lower a car's center-of-gravity by several inches, making for a better-handling chassis.
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