for accessories (such as the alternator and water pump). The left bank of the engine is on the left side of the car (when looking from behind the car), and vice versa for the right bank of the engine. For a transverse engine located at the front of the car, whether the front of the engine is at the left-hand or right-hand side of the car is best determined based on the side of the car where the transmission is located (which corresponds to the rear of the engine). Most transverse engine front-wheel drive models have the front of the engine at the right-hand side of the car (except for many Honda cars). As a consequence, the left bank of a transversely V engine is usually closest to the front of the car. For cars where the engine is installed 'backwards' (i.e. the transmission is closer to the front of the car than the engine, or under the engine), cylinder #1 is located towards the rear of the car. This is the case for the Citroën Traction Avant, Saab 99, Saab 900 and many rear-engine cars. Numbering systems for ship engines Contrary to most car engines, a ship's engines are often numbered starting from the end of the engine with the power output. Large diesel truck and locomotive engines, particularly of European manufacture, may also be numbered this way. Cylinders on V engines often include a letter representing the cylinder bank. For example, a V6 engine could have cylinders A1-A2-A3-B1-B2-B3, with cylinders A1 and B1 located at the power output end of the engine. Common firing orders Common firing orders are listed below. For V engines and flat engines, the numbering system is L1 for the front cylinder of the left bank, R1 for the front cylinder of the right bank, etc. In two-cylinder engines, the cylinders can either fire simultaneously (such as in a flat-twin engine) or one after the other (such as in a straight-twin engine). In straight-three engines, there is no effective difference between the possible firing orders of 1-2-3 and 1-3-2. Straight-four engines typically use a firing order of 1-3-4-2, however some British engines used a firing order of 1-2-4-3. Flat-four engines typically use a firing order of R1-R2-L1-L2. Straight-five engines typically use a firing order of 1-2-4-5-3, in order to minimise the primary vibration from the rocking couple. Straight-six engines typically use a firing order