Friday, December 13, 2019

How V8 Engines Work - A Simple Explanation

V8 engines operates under the same basic principles as any other gasoline four-stroke engine. First the piston pulls in air and fuel as it moves downward, then it compresses that air and fuel as the piston moves upward. A spark plug fires, igniting the air/fuel mixture and forcing the piston downward. Finally the piston pushes out the exhaust gases on its way back up, before for the cycle repeats itself.

In a V8 engine, this cycle is happening in 8 different cylinders, at different times. Instead of multiple cylinders firing at the same time, you want them to be spread out so that power delivery is smooth. For this Chevy V8, the firing or is 1, 8, 7, 2, 6, 5, 4, 3. With 8 cylinders, there is a cylinder firing for every 90 degrees of the crankshaft rotating, which means at any point in time, there are two cylinders on the power stroke.

With regards to the valvetrain, the intake air comes from the top of the engine, and into the sides of the cylinder head. The exhaust flows to the sides of the engine, exiting the exhaust valves from the cylinder head. In this LS3 model, there is a single intake valve and a single exhaust valve, though it’s also common to see engines with two intake valves and two exhaust valves. The larger valve is the intake valve, and the smaller valve is the exhaust valve.

The pushrod valvetrain gets its name from the metal pushrods which activate the rocker arms which open up the valves. The camshaft, located in the center of the V, has lobes on it which push the push rods up, opening the appropriate valves. For a full explanation of V8 engines, check out the video!