How V8 Engines Work - A Simple Explanation

The Basics of V8 Engines: A Comprehensive Guide

V8 engines get their name from having a cylinder block in the shape of a V, with 90 degrees between the two banks of cylinders. The numbering starts at the front most piston on the right and then works its way back to number 8. This engine operates under the same basic principles as any other gasoline four-stroke engine, focusing on just a single cylinder first.

The Piston: A Crucial Component

The piston is a vital component of any engine, and in a V8, it's responsible for pulling in air and fuel as it moves downward, compressing that air and fuel as the piston moves upward, and then firing a spark plug to ignite the air-fuel mixture. As the piston moves downward, it pushes out the exhaust gases on its way back up. This cycle repeats itself, but in an eight-cylinder engine, this cycle is happening in eight different cylinders at different times.

Firing Order: A Matter of Smooth Power Delivery

In a V8 engine, there's a specific firing order to ensure smooth power delivery. For this Chevy V8, the firing order is 1, 8, 7, 2, 6, 5, 4, and 3. This means that at any point in time, there are two cylinders on the power stroke. A four-cylinder engine would only have one cylinder firing at a time, resulting in less smooth power delivery.

Valve Train: The Path to Air Flow

The valve train is responsible for letting air flow into the engine and out of it. Intake air comes from the top of the engine and into the sides of the cylinder head. Exhaust gases flow to the sides of the engine, exiting through the exhaust valves from the cylinder head.

Cylinder Head: A Single Valve or Two?

In this particular V8 engine, there's a single intake valve and a single exhaust valve, although it's 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. This pushrod valve train gets its name from the metal push rods that activate the rocker arms, which open up the valves.

The Camshaft: A Key Player

The camshaft is located in the center of the V of the engine block and has lobes on it. These lobes push the push rods up, opening the appropriate valves. The camshaft operates the valves and is geared to the crankshaft, which ultimately drives the pistons.

Crankshaft: Balancing the Engine

The crankshaft is a critical component of any V8 engine, as it balances the engine's movement. For every two rotations of the crankshaft, the camshaft rotates once. When you remove the oil pan from the engine, you can see the operation of the crankshaft. The crankshaft is offset by 90 degrees to counterbalance the force generated by the pistons.

Counterbalance Weights: A Key to Smooth Operation

The two pistons across from each other are actually paired to the same crankshaft bearing. As one piston reaches the top, the counterbalance weights directly across from it balance out the force as it rotates another 90 degrees. This balances out the rocking moment caused by the pistons' movement.

A Crossplane V8: A Smooth-Running Engine

This particular V8 is what's called a crossplane V8, meaning each connection point on the crankshaft is offset 90 degrees. The pistons operate in two planes or a cross plane. This design provides several advantages, including large displacement, which often correlates with generating lots of power, and a compact, rigid form that results in very little vibration.

However, compared to some engines, this style has a relatively higher center of gravity and is complex, as it requires two separate cylinder heads rather than just one like an inline engine. Additionally, while producing more power, these engines are still quite heavy compared to smaller-style engines.

Conclusion

In conclusion, V8 engines are remarkable pieces of machinery that produce smooth, powerful performance. By understanding the basics of how they work, including the firing order, valve train, and crankshaft design, we can appreciate the complexity and sophistication that goes into creating these incredible machines.

"WEBVTTKind: captionsLanguage: enHello everyone and welcome in this videowe're going to be learning how V8 engines workstarting off simple and then diving into the details of the 3D printed Chevy Camaro lS3 V8engine seen here so starting with the very obviousV8 engines get their name from having a cylinder block in the shape of a V in this case at 90 degrees andfrom having eight cylinders in this case the numbering starts at the front most piston on the rightand then works its way back 1, 2, 3, 4, 5, 6, 7, and 8.This engine operates under the same basic principles as any other gasoline four-stroke enginefocusing on just a single cylinder first the piston pulls in air and fuel as it moves downwardthen it compresses that air and fuel as the piston moves upward next a spark plug firesigniting the air fuel mixture and forcing the piston downward andfinally the piston pushes out the exhaust gasses on its way back up before the cycle repeats itself now in a V8 enginethis cycle is happening in eight different cylinders at different timesinstead of multiple cylinders firing at the same time you want them to be spread out so that power delivery is smooth forthis Chevy V8the firing order is 1, 8, 7, 2, 6, 5, 4, 3with eight cylindersthere is a cylinder firing for every 90 degrees of the crankshaft rotatingwhich means that at any point in time there are two cylinders on the power stroke afour-cylinder engine would only have one cylinder firing at a time meaning the power delivery wouldn't be as smoothso now let's look at the valve train to see how air flows in and out of the enginethe intake air comes from the top of the engine and into the sides of the cylinder headthe exhaust flows to the sides of the engineexiting the exhaust valves from the cylinder head looking at the cylinder head removed from the engine you can see thatthere is a single intake valve and a single exhaust valve though it's also common to see engines with two intake valves and two exhaustvalves in this case the larger valve is the intake valve and the smaller valve is the exhaust valvethe pushrod valvetrain gets its name from the metal push rodswhich activate the rocker arms which open up the valves the camshaftlocated in the center of the V of the engine block has lobes on itwhich pushed the push rods up opening the appropriate valves hereyou can see a simpledemonstration of the push rod being used to open up the intake valveit presses against the rocker arm seen in red forcing the intake valve open the camshaftwhich operates the valves is geared to the crankshaftmwhich is what ultimately all the Pistons are trying to rotate for every two rotations of the crankshaft thecamshaft rotates once if we remove the oil pan from the engine we can see the operation of the crankshaft thecrankshaft is the yellow shaft and there are added weights to it for balancing the engine the connecting rods are in brown which connect thecrankshaft to the Pistons what's cool about V8engines is that the two pistons across from one another are actually paired to the same crankshaft bearing so moving on to those large yellowcounterbalance weightslooking at the first pair of cylindersyou'll notice that as one piston reaches the very top the counterbalance is directly across from itbalancing out the force as it rotates another 90 degrees it now counters the other Pistons forcerotating another 90 degrees the first piston has reached the bottom and the weights counter that downward force with an upward force and thenfinally another 90 degrees later the second piston reaches the bottomwhere its downward force is once again countered with an upward force.This is actually balancing out a rocking moment caused by the Pistons movement in full swingthough the whole engine may look complicated from a balancing standpointit actually is extremely smooth running with no first or second ordervibrations and only a first-order moment that is countered out through the crankshaft designall of this is to say that the engine runs very smoothly now this particular V8is what is called a crossplane V8which means each connection point on the crankshaft isoffset 90 degrees meaning the pistons operate in two planes or a cross plane the alternative is a flat plane crankshaft where the pistons are simply offset 180 degrees meaning they all operate in a single or flat planethe advantages of this engine style include its largedisplacement which often correlates with generating lots of power while in a generally compact and very rigid form they have very little vibrationhowever compared to some enginesthey have a relatively higher center of gravity and are complexsince they require two separate cylinder heads rather than just one like an inline engine generally speaking althoughthey are compact in form they are still quite heavy compared to smaller style engines though of course while producing more powerif you found this helpfulI have included links to other videos you may enjoyalso a huge shout out to Erik Harrell for lending me the 3D printed V8 engine.I will include links to his work in the video description as always feel free to leave any questions or comments below andthanks for watching.\n"