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In a conventional engine, the correct firing order is obtained by the correct placement of the spark plug wires on the Distributor . In a modern engine with an Engine Management System and Direct Ignition , the Electronic Control Unit (ECU) takes care of the correct firing sequence. These are some usual firing orders: CYLINDER NUMBERING In a Straight Engine the spark plugs (and Cylinder s) are numbered, starting with #1, from the front of the engine to the rear. In most Rear Wheel Drive Cars , the engine is Longitudinally Mounted and the front of the engine also points to the front of the car. In Front Wheel Drive cars with a Transverse Engine , the front of the engine usually points towards the righthand side of the car; in any case the front of the engine is the part where the pulleys for the accessories (such as the Alternator and Water Pump ) are. In front wheel drive cars with Longitudinally Mounted engines, most often the front of the engine will point towards the front of the car, but some manufacturers ( Saab , Citroën ) in some models place the engine 'backwards', with #1 towards the Firewall . In a Radial Engine the cylinders are numbered around the circle, with the #1 cylinder at the top. There are almost always an odd number of cylinders, as this allows for a constant every-other-piston firing order: for example, with a single bank of 7 cylinders, the order would be ...2-4-6-1-3-5-7-2.... The numbers are usually Cast on the Cylinder Head or the intake Manifold or the Valve cover(s). In a V Engine , cylinder numbering varies among manufacturers. Generally speaking, the most forward cylinder is numbered 1, but some manufacturers will then continue numbering along that bank first (so that side of the engine would be 1-2-3-4, and the opposite bank would be 5-6-7-8) while others will number the cylinders from front to back along the crankshaft, so one bank would be 1-3-5-7 and the other bank would be 2-4-6-8. (In this example, a V8 is assumed). To further complicate matters, manufacturers may not have used the same system for all of their engines. It is important to check the numbering system used before comparing firing orders, because the order will vary significantly with crankshaft design (see Crossplane ). As an example, the well-known Chevrolet Small-Block Engine has cylinders 1-3-5-7 on the left hand side of the car (right hand when looking from the front), and 2-4-6-8 on the other side, and uses a firing order of 1-8-4-3-6-5-7-2. Note that the order alternates irregularly between the left and right banks; this is what causes the famous 'burbling' sound of this type of engine. {Link without Title} In the Audi and Ford V8 engines cylinders are 1..4 (same side as right wheel) counting from the front of the car (timing end of the engine). Cylinders 5..8 got from front to rear on the same side as left wheels. Ships Contrary to most car engines, a ships engine or a power plant engine is numbered from the flywheel end towards the free end. In ship and power plant V-type engines the numbering is A1... and B1... where the A-bank is on the left hand side, looking from the flywheel end and B-bank is on the right hand side. TRIVIA
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