V-8 engines are one of the most common styles of engine across the entire automotive industry, especially when the goal is to produce a lot of power with a smooth delivery.
So, how does such an engine work? Jason Fenske of Engineering Explained is here to shed light on how a V-8 engine operates. Specifically, he uses a General Motors’ popular LS3 6.2-liter V-8, found in the sixth-generation Corvette and fifth-generation Camaro.
Foremost, the V-8 operates like any other gasoline-powered four-stroke engine. The cylinder pulls in air and fuel, compresses the air and fuel, a spark plug ignites the mixture to create power and forces the piston downward, and finally, the piston pushes exhaust gases out as it travels back up. The cycle happens in eight different cylinders at different times, and the cycle is spread out across the cylinders for smooth power delivery. In the LS3 V-8, the firing order is 1-8-7-2-6-5-4-3, which has a cylinder firing for every 90 degrees of the crankshaft’s rotation.
Next, we move into the valvetrain. Intake air comes from the top of the engine and into the sides of the cylinder head and exhaust flows through the exhaust valves on the side of the cylinder head. The cylinder head itself includes a single intake valve and a single exhaust valve. In the video, we see the larger valve in the intake and the smaller valve is for the exhaust. Since we’re looking at a Chevrolet V-8 engine, there are pushrods present. The pushrods activate the rocker arms that open up the valves. The alternative is a chain-driven overhead cam design, which at GM you’ll now find in Cadillac’s latest V-8.
As for the pushrods, they work via the camshaft’s lobes that activate the pushrods to open up the appropriate valve as it turns. Now, the camshaft that operates the valves is connected to the crankshaft. For every two crankshaft rotations, the camshaft rotates once, and Jason removes the oil pan to show how the crankshaft operates. Weights are added to the crank to balance the engine and connecting rods connect the crank to the pistons.
So, as the piston reaches the top of the cylinder, the counterbalance is directly across from it to balance out the force. And at another 90 degrees, it counters out the other piston’s force. As the piston returns to the bottom, the weight counters all the downward force with an upward force. Although it sounds complex, the entire process is actually a simple way to create a smooth engine without much vibration.