A V8 engine is an eight-cylinder V engine with the cylinders mounted on the crankcase in two sets of four cylinders, in most cases set at a right angle to each other, but sometimes at a narrower angle, with all eight pistons driving a common crankshaft.
In its simplest form, it is basically two inline-four engines sharing a common crankshaft. However, this simple configuration, with a flat- or single-plane crankshaft, has the same secondary dynamic imbalance problems as two straight-4s, resulting in vibrations in large engine displacements. Since the 1920s most V8s have used the somewhat more complex crossplane crankshaft with heavy counterweights to eliminate the vibrations. This results in an engine that is smoother than a V6, while being considerably less expensive than a V12 engine. Most racing V8s continue to use the single plane crankshaft because it allows faster acceleration and more efficient exhaust system designs;