How Many Spark Plugs In A V8 Engine?

Regardless of the vehicle type, every vehicle’s motor relies on spark plugs. Understanding an engine and its spark plugs makes diagnosing and correcting vehicle problems easier.

The question “How many spark plugs in a V8” may seem easy to answer, but the amount of spark plugs depends on several factors.

How Many Spark Plugs Does A V8 Have?

V8 engines operate with eight cylinders. Most engines have one spark plug per cylinder, so an eight-cylinder engine typically has eight spark plugs.

However, some engine designs use two spark plugs per cylinder to achieve dual ignition technology.

Dual ignition technology gives better horsepower and cuts down on emissions. Depends on the number of wires or coils.

Whether an engine uses spark or dual ignition, counting the spark plug wires defines how many spark plugs an engine has.

Hemi V8 motors use coils instead of cables to power their spark plugs, with each coil connecting to two spark plugs.

Regular V8 engines have eight spark plugs connected with eight wires. Hemi V8 engines use eight spark plug coils, which result in 16 spark plugs.

Diesel car engines use glow plugs instead of spark plugs. Glow plugs operate like spark plugs but use superheated compressed air instead of a sparked air-fuel mixture to provide power.

Historically, vehicle motors with a higher number of spark plugs provide greater torque and horsepower, better fuel economy, and fewer emissions.

Modern engines now use a single spark plug instead of dual ignition to achieve similar results.

What Are Spark Plugs And How Do They Work?

A spark plug is a tube-shaped insulated plug that fits on the top of a cylinder head’s combustion chamber.

As a motor runs, its piston pushes down into the cylinder and sucks a combination of air and fuel into the combustion chamber.

When the piston comes back up, the air-fuel mixture compresses, and the spark plug creates a spark to ignite the mixture.

The pressure of this forces the piston to push down again.

This process generates power for the engine and repeats throughout as long as the engine runs.

Each cylinder in the engine works the same way, producing the energy a vehicle needs to stay on.

What Are Spark Plugs Made Of?

The exterior of a spark plug ensures a safe connection between the wire or coil and the firing component in the spark plug. Inside, a spark plug has a central electrode copper core.

This core has a porcelain coating to help keep it from overheating. A nickel alloy covering, often visible at the spark plug’s tip, wraps around the porcelain.

When purchasing a new spark plug, Original Equipment Manufacturer (OEM) spark plugs work better than aftermarket spark plugs.

OEM plugs offer the best fuel economy and last longer than aftermarket versions. While nickel alloy spark plugs do the job, different metals provide better results.

Silver Spark Plugs

Silver spark plugs don’t appear as much today as they used to. Older vehicles may accommodate silver spark plugs, but newer vehicles require different types of spark plugs.

Copper Spark Plugs

Another older type of spark plug uses copper. Copper has a low melting point, so while they still work well for older vehicles, they don’t last as long as higher-quality spark plugs.

Platinum Spark Plugs

Platinum spark plugs build up less carbon and last longer than copper spark plugs.

Iridium Spark Plugs

Iridium spark plugs offer the highest melting point of any other spark plug material. These spark plugs last longer than silver, copper, or platinum.

How Long Do Spark Plugs Last?

Spark plugs wear out and need a replacement for an engine to continue working. Many vehicles include a spark plug’s approximate lifespan in their owner’s manuals.

Check any new car’s manual to see its spark plugs’ ideal lifespan. If buying a used vehicle, replace the spark plugs soon after purchasing to keep the motor healthy.

Keeping a record of replacements and repairs makes it easier to know when to replace spark plugs.

Spark plug lifespans differ depending on the material in the spark plug:

  • Silver: Up to 20,000 miles
  • Copper: Between 30,000 and 50,000 miles
  • Platinum and Iridium: Between 50,000 miles and 120,000 miles

How To Know When To Replace Spark Plugs

Some ways to know when to replace spark plugs include:

  • Trouble getting the vehicle started
  • The vehicle temporarily starts before dying
  • Exhaust produces smoke
  • Higher fuel consumption
  • Engine hesitates to start
  • Check engine light comes on

When checking spark plugs by sight, look for a widened spark plug gap. If a spark plug has too much space between its center electrode and ground electrode, the spark plug gap won’t allow for proper connection.

How To Replace Spark Plugs

The speed and ease of a spark plug replacement depend on engine design, as some spark plugs can be harder to reach and adjust.

Remember that the answer to, “How many spark plugs does a V8 have” depends on whether the motor uses coils or wires.

Steps To Replacing Spark Plugs

1. Park the vehicle on a flat surface and wait for the engine to cool.

2. Pop the hood and remove the engine cover.

3. Find the spark plugs and note the cables or coil packs. Check those to make sure they are in good condition.

4. Remove the cables or coil packs from each spark plug.

5. Unscrew each spark plug from the cylinder head.

6. Use one spark plug to check and make sure the spark plug gap matches the required space.

7. Place the new spark plugs and tighten each plug to the prescribed torque. 8. Try turning the car on.

Healthy V8 Engines Depend On Good Spark Plugs

Knowing how many spark plugs are in a V8 may be essential, but understanding how to check and replace spark plugs makes caring for an engine easier.

Make it a priority to know how many spark plugs an engine has, what kind of spark plugs work best for the vehicle, and how to recognize symptoms of bad spark plugs.


Garry is the happy owner of a funky 2018 Nissan Juke Ti-S AWD. After growing up around his family’s mechanics shop, he is passionate about bringing budget-friendly car care to every driver. Garry has a business degree and is a car enthusiast.