Most people know what spark plugs are and how they work, but believe it or not, V8 engines vary greatly in how many spark plugs they utilize. Here’s all you need to know about the number of spark plugs in a V8.
A V8 generally has 8 spark plugs, one for each cylinder. Some, like the 6.4 Hemi, allow for two spark plugs to be connected to a single cylinder, making 16 plugs for a twin spark engine.
With the complexity of modern engines, the number of spark plugs a V8 requires can seem puzzling. While the majority of V8s have 8 spark plugs, there are exceptions.
In this blog post we’ll be taking a deep dive into one amazing component — spark plugs.
We’ll answer the seemingly simple question of “how many spark plugs in a V8” as well as look at what role these tiny little components play in helping keep your car running smoothly.
How Are Spark Plugs Used in V8s?
A spark plug delivers the current from the ignition system to the combustion chamber, igniting the air/fuel mixture via an electric spark.
In most cases, spark plugs are used per cylinder in a V8 engine. Each plug provides the explosive force to push the piston down. This force then turns the crankshaft, which transfers energy to the transmission.
The right bank contains cylinders 1, 2, 3, and 4, while the left contains 5, 6, 7, and 8. The spark fire in pairs with the order generally being 1, 8, 4, 3, 6, 5, 7, 2.
Spark plugs are one of the hardest working parts of a combustion engine. In fact, a spark plug can ignite 400 times a second per cylinder. Pretty amazing when you think about it.
Why Do Some V8s Have 16 Spark Plugs?
Some V8s have 16 spark plugs, which makes the engine a twin spark engine. They work on the same principle, with each spark igniting the fuel-air mixture in a set sequence.
The difference is that a twin spark engine allows the fuel-air mixture to be burnt more quickly and completely.
It’s a simple change but is generally associated with an improvement in combustion efficiency. If any of the cylinders don’t fire properly, then the engine performance will be noticeably worse.
Spark plugs are fairly cheap, only costing between $5 and $20 for replacements. The price may vary depending on the model of vehicle you have.
How Often Should You Change Spark Plugs in a V8?
High-end platinum or iridium spark plugs will last 100,000 miles before needing replaced. However, copper plugs are not as durable, and require replacement between 35,000 to 50,000 miles.
How Much Does it Cost to Replace Spark Plugs on a V8?
Spark plug replacement at a dealership or local shop will cost between $115 and $200.
The cost of a spark plug is typically between $5 and $20 each. However, much of the cost to replace spark plugs is for the labor.
Can a V8 Have 6 Spark Plugs?
No, V8 engines require at least one spark plug per cylinder. However, some engines, such as the Hemi V8 engine uses 2 plugs per cylinder.
Final Thoughts
It stands to reason that a V8, an engine with 8 cylinders, also has 8 spark plugs to ignite each of those cylinders. The onboard computer regulates the firing rhythm so that each piston is firing in unison as the fuel-air mixture is ignited, driving the crankshaft and providing torque to turn the wheels.
Some V8s, however, allow for twin sparking, which sees two spark plugs firing per cylinder. On paper, twin spark V8s have more even and complete ignition, allowing for better combustion efficiency.
Managing Editor
Christopher is an automotive technical writer. When he’s not at the local autocross event, he can often be found working on one of his cars. Specializes in automotive class action law, industry trends, and automotive maintenance. Email me direct, or learn more about us
