The flat-plane crank (sometimes flatplane) is a type of

crankshaft A crankshaft is a mechanical component used in a reciprocating engine, piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating Shaft (mechanical engineering), shaft containing one or more crankpins, ...

for use in

internal combustion engines An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal comb ...

that has a 180-degree angle between crank throws.

Details

Flat-plane cranks are used in V-configuration engines, generally with

eight cylinders The engine configuration describes the fundamental operating principles by which internal combustion engines are categorized. Piston engines are often categorized by their cylinder layout, valves and camshafts. Wankel engine, Wankel engines are o ...

. Cadillac introduced a V8 flat-plane crank engine in 1923. Engine movingparts

Inline-four A straight-four engine (also referred to as an inline-four engine) is a four-cylinder piston engine where cylinders are arranged in a line along a common crankshaft. The majority of automotive four-cylinder engines use a straight-four layout ( ...

cylinder engines almost all use flat-plane cranks, and thus are not usually identified as such. However, there are a few exceptions with crossplane cranks. Flat plane crank

The flat-plane crankshaft was used in the World War II

Sherman Tank The M4 Sherman, officially medium tank, M4, was the medium tank most widely used by the United States and Western Allies in World War II. The M4 Sherman proved to be reliable, relatively cheap to produce, and available in great numbers. I ...

in the

Ford GAA engine The Ford GAA engine is an American all-aluminum 32-Poppet valve, valve Overhead camshaft engine, DOHC 60-degree gasoline-fueled liquid-cooled V8 internal combustion engine with a flat-plane crank. It was designed and produced by the Ford Motor Com ...

, an all-aluminium 32-

valve A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or Slurry, slurries) by opening, closing, or partially obstructing various passageways. Valves are technically Pip ...

DOHC An overhead camshaft (OHC) engine is a piston engine in which the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combus ...

60-degree liquid-cooled V8. However, the flat-plane design is no longer widely used in most mass production V engines as it is more prone to vibration and is inherently much louder than a

crossplane The crossplane or cross-plane is a crankshaft design for piston engines with a 90° angle (phase in crank rotation) between the crank throws. The crossplane crankshaft is the most popular configuration used in V8 road cars. Aside from the V8 alre ...

crankshaft. However, due to its simpler construction requiring less counterweight, it is inherently lighter with a higher rev limit. For this reason, it remains useful in sports and racing cars. Flat-plane crankshafts are generally associated with European sports cars such as

Ferrari Ferrari S.p.A. (; ) is an Italian luxury sports car manufacturer based in Maranello. Founded in 1939 by Enzo Ferrari (1898–1988), the company built Auto Avio Costruzioni 815, its first car in 1940, adopted its current name in 1945, and be ...

and Lotus V8 engines, and cross-plane cranks with American manufacturers. There are some exceptions such as the Ferrari-designed crossplane crank V8 of the Lancia Thema 8.32 and the flat-plane crank 2014–2023 Ford Mustang GT350. The 2023 model year Chevrolet Corvette Z06 has the largest flat-plane V8 ever seen in production cars at 5.5 litres. The way in which a flat-plane works within a V8 engine is more like two in-line 4-cylinder engines mated together, with the firing order of each order being in a Right-Left-Right-Left-Right-Left-Right-Left pattern. Being in this in-line configuration allows for the engine to

rev Rev, REV or Rév may refer to: Abbreviations Rev. * Rev., an abbreviation for revolution, as in Revolutions per minute * Rev., an abbreviation for the religious style The Reverend * Rev., the abbreviation for Runtime Revolution, a development en ...

much faster, making it more suitable for racing engines.

References

{{Reflist Crankshafts

Details

See also

References