A V5 engine is a five-cylinder piston engine where the cylinders share a common crankshaft and are arranged in a V configuration.

Even compared to the fairly rare straight-five engine, V5 engine designs are very uncommon. The first production V5 was the 1997–2007 Volkswagen Group VR5 engine. It is arguably not a true V5 engine, as all the cylinders share a single cylinder head. However, Honda produced a true V5 motorcycle racing engine, used in the RC211V.

In the early 1980s, Oldsmobile developed a prototype 2.5 L (153 cu in) V5 diesel engine, however it never reached production stages and the project was subsequently abandoned.^[1] The engine is based on the Oldsmobile V6 diesel engine with the fuel injection pump in the location of the "missing" sixth cylinder.^[2] A prototype engine is on display at the RE Olds Museum in Lansing, Michigan.

The only V5 automobile engine to reach production was the 2.3 L (140 cu in) "VR5" engine manufactured by Volkswagen from 1997 to 2006. Based on Volkswagen's VR6 engine, the VR5 was a narrow-angle engine with staggered cylinders (three cylinders on one bank and two on the other) sharing a single cylinder head.^[3] As per the VR6 engine, the angle between the banks was 15 degrees. Initial versions used 2 valves per cylinder, however, an update in 2000 resulted in a total of 4 valves per cylinder and the addition of variable valve timing.

The Honda RC211V, a MotoGP racing motorcycle which competed in the 2002–2006 seasons, used a V5 engine.^[4] The transversely-mounted 990 cc (60 cu in) engine had three cylinders at the front, two cylinders at the rear and a V-angle of 75.5 degrees. The engine used 4 valves per cylinder.

In the last days of the BSA motorcycle manufacturer, the factory design team produced plans for a modular range of four engines, all using a 200cc cylinder. (It was planned to increase the cylinder capacity to up to 250cc in due course). The range, which never went further than the drawing board, comprised:

• 200cc single
• 400cc parallel twin
• 600cc triple
• 1,000cc V5 muscle bike

(The company avoided the perhaps obvious 800cc straight-four option, to avoid direct competition with the major Japanese factories that already dominated the market with such machines).^[5]

• Straight-five engine