Flatplane

The flatplane or flat-plane is a type of crankshaft for use in engines with a 180 Degree angle between crank throws.

The Flat-plane is used in V configuration engines generally with 8 cylinders.

Inline-four 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.

The Flat-plane crankshaft is a design that is no longer used in most mass production road cars as it carries more vibrations and is inherently much louder than a Crossplane crankshaft; however its higher rev limit means it remains useful in sports and racing cars. Flat-plane crankshafts are generally associated with European sports cars such as Ferrari and Lotus V8s and cross-plane cranks with American manufacturers; however there are some exceptions such as the Ferrari-designed crossplane crank V8 of the Lancia Thema 8.32 and the flatplane crank Ford Mustang GT350.

The way in which a Flat-plane works within a V8 engine is more like 2 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 4 configuration allows for the engine to rev much higher up to 8000rpm making it more suitable for racing engines.

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Wikipedia