A V6 engine is a V engine with six cylinders mounted on the crankcase in two banks of three cylinders, usually set at either a right angle or an acute angle to each other, with all six pistons driving a common crankshaft. It is the second most common engine configuration in modern cars after the inline four.
The V6 is one of the most compact engine configurations, shorter than the straight 4 and in many designs narrower than the v8 engine, and is well suited to the popular front-wheel drive layout. It is becoming more common as the space allowed for engines in modern cars is reduced at the same time as power requirements increase, and has largely replaced the inline-6, which is too long to fit in many modern engine compartments. Although it is more complicated and not as smooth as the inline 6, in addition to being more compact it is more rigid and less prone to torsional vibrations in the crankshaft. The V6 engine has become widely adopted for medium-sized cars with engine displacements between 2.4 and 3.2 litres, often as an optional engine where a straight-4 is standard, or as an economy engine where a V8 is a higher-cost option.
The first V6 was introduced by Lancia in 1950 with the Lancia Aurelia. Other manufacturers took note and soon other V6 engines were in use. In 1959, GM introduced a heavy duty 305 cubic inch (5 liter) 60-degree V6 for use in their pickup trucks and Suburbans, an engine design that was later enlarged to 478 cubic inches (7.8 liters) for heavy truck and bus use.
The design really took off after the 1962 introduction of the Buick Special, which offered a 90 degree V6 with uneven firing intervals that shared some parts commonality with a small Buick V8 of the period. Though the Buick Special met consumer resistance due to its excessive vibration, it was the first instance of a mass-produced V6 engine designed specifically for passenger automobiles. In 1983 Nissan produced Japan's first V6 engine with the VG series.
Modern V6 engines commonly range in displacement from 2.5 L to 4.3 L, though larger and smaller examples have been produced.
