V8 engine

A V8 engine is an eight-cylinder piston engine in which two banks of four cylinders share a common crankshaft and are arranged in a V configuration.

The first known V8 was the Antoinette, designed by Léon Levavasseur, and built in 1904 by the French Antoinette company for use in speedboat racing, cars, and later, airplanes.

Also in 1904, V8 engines began small-scale production by Renault and Buchet for use in race cars.^{[citation needed]}

Most engines use a V-angle (the angle between the two banks of cylinders) of 90 degrees. This angle results in good engine balance, which results in low vibrations. However, the downside is the greater width of the engine compared to those that use a smaller V-angle.

V8 engines with a 60-degree V-angle were used in the 1996–1999 Ford Taurus SHO, the 2005–2011 Volvo XC90, and the 2006–2009 Volvo S80. The Ford engine used a 60-degree V-angle because it was based on a V6 engine with a 60-degree V-angle. Both the Ford and Volvo engines were used in transverse engine chassis, which were designed for a front-wheel-drive layout (with an on-demand all-wheel drive system in the case of the Volvos). To reduce the vibrations caused by the unbalanced 60-degree V-angle, the Volvo engines used a balance shaft and offset split crankpins. The Rolls-Royce Meteorite tank engine also used a 60-degree V-angle, since it was derived from the 60 degree V12 Rolls-Royce Meteor which in turn was based on the Rolls-Royce Merlin V12 engine.

Other V-angles have been used occasionally. The Lancia Trikappa, Lancia Dilambda, and Lancia Astura, produced 1922–1939, used narrow angle V8 engines (based on the Lancia V4 engine) with V-angles of 14–24 degrees. The 1932 Miller four-wheel drive racing cars used a V8 engine with a V-angle of 45 degrees. The 8-cylinder versions of the 1945 through 1966 EMD 567 diesel locomotive engine also used a V-angle of 45 degrees.

Most V8 engines fitted to road cars use a cross-plane crankshaft since this configuration produces less vibration due to the perfect primary balance and secondary balance. The cross-plane crankshaft has the four crank pins (numbered from the front) at angles of 0, 90, 270, and 180 degrees, which results in a cross shape for the crankshaft when it is viewed from one end.

The rumbling exhaust sound produced by a typical cross-plane V8 engine is partly due to the uneven firing order within each of the two banks of four cylinders. A usual firing order of L-R-L-L-R-L-R-R (or R-L-R-R-L-R-L-L) results in uneven intake and exhaust pulse spacing for each bank. When separate exhaust systems are used for each bank of cylinders, this uneven pulsing results in the rumbling sound typically associated with V8 engines. However, racing engines seek to avoid these uneven exhaust pressure pulses to maximize the power output. The 1960s cross-plane V8 racing engines used long primary exhaust pipes (such as the Ford GT40 endurance racing car) or located the exhaust ports on the inside of the V-angle (such as the Lotus 38 IndyCar) to link the exhaust systems from each bank and provide even exhaust gas pulses),.