How Many Spark Plugs Are In A V8 Engine?

There is one question about spark plugs that most people have when it comes to engine mechanics: How many spark plugs are in a V8 engine? Answering the question is usually simple. 8 is the answer for spark plugs, but the real answer varies based on the engine type, design, and manufacturer.

In the complete guide, we will look at the importance of spark plugs, answer how some V8 engines need more than 8 spark plugs, and also include basic maintenance to upgrade the engine performance.

What Is a Spark Plug (and Why Does It Matter)?

A spark plug is small but at the heart of an internal combustion engine. Its short, stout shape is essential for igniting the air-fuel mixture within the combustion chamber of the engine. This detonation is controlled, creating the explosion that powers the engine.

One spark plug (or several plugs) is needed per cylinder of air-fuel mixture for efficient combustion in a V8 engine. The engine can misfire, lose power, or have poor fuel efficiency, which comes with bad spark plugs.

V8 Internal Combustion Engine Standard Spark Plug Configuration

Old-School V8 Engines — 8 Spark Plugs

In nearly all traditional V8 motors, the engine has one spark plug for each cylinder, thus, there are a total of 8 sparkplugs. Each spark plug ignites the air-fuel mixture in the corresponding cylinder.

Dual Ignition V8 Engines — 16 Spark Plugs

It may also be worth noting that many of the larger power V8 engines (especially those targeting increased power, efficiency, or emissions control) often have two spark plugs per cylinder. That makes for 16 spark plugs all in all.

Why Dual Spark Plugs?

Better Combustion Burn: The fuel-air mixture ignition is faster with dual spark plugs, which leads to better combustion for performance.

Less Unburned Fuel: More efficient combustion means less unburned fuel, which directly leads to harmful emissions.

Higher Power: Dual spark plug engines also generally provide more horsepower and torque.

What V8s Have 16 Spark Plugs?

Most V8 engines are built with 8 spark plugs, except for some notable exceptions:

Dodge HEMI V8 Engines

Dodge 5.7L HEMI, 6.4L HEMI, and 6.2L Hellcat V8 engines feature two spark plugs per cylinder, which equals 16 spark plugs. This construction helps with combustion and emissions, notably under load.

Mercedes-Benz V8 Engines

A dual ignition system is also used on some Mercedes-Benz V8 engines, particularly the AMG performance models, which have 16 spark plugs.

Specific Racing and Performance Engines

Motorsport or racing-focused high-performance V8 engines or specialized high-power V8 designs may use a dual-spark layout to optimize power and combustion.

How Are 16 Spark Plugs Not Standard in All V8 Engines?

There are certainly some benefits to such a system, but most V8s run just fine with a single plug per cylinder. Consumer vehicles are usually designed to be more cost-efficient, easier to maintain, and simpler than those made by manufacturers.

Modern direct fuel injection (DI) systems and advanced combustion technologies have also improved performance without the need for additional spark plugs.

How to Determine How Many Spark Plugs Are in Your V8 Engine?

If you want to know how to check whether your V8 engine has 8 or 16 spark plugs, here’s the answer:

Owner’s Manual: The best source of information for your specific engine’s specs.

Look in the engine bay: check the spark plug wires or ignition coil connectors. If your engine has a dual-cochlear setup per cylinder, you have 16 spark plugs translational.

Verify Cylinder Head Design: Most dual spark plug engines have separate plug locations in each cylinder.

V8 Engine Common Spark Plug Issues

Common spark plug issues can affect performance, even in V8s, whether they have 8 or 16 spark plugs. Spot these problems early, and you can save hundreds on repairs.

Spark Plug Fouling

In this case, fouling means carbon, oil, or fuel deposits accumulated on the tip of the spark plug that could prevent a proper ignition.

Symptoms:

• Rough idling
• Poor acceleration
• Reduced fuel efficiency

Solution:

• Check and clean spark plugs periodically.
• Spark plugs: Replace worn or heavily fouled spark plugs as required.

Misfires

A bad spark plug can cause a misfire, which will lead to engine stuttering or shaking.

Symptoms:

• Engine hesitation
• Exhaust popping noises
• Check engine light activation

Solution:

Sometimes, current spark plugs must be changed before the expected time to bring the engine back to a smooth and normal performance.

Worn Electrodes

The spark plug electrodes wear down over time and lose the strength and efficiency of the spark.

Symptoms:

• Trouble starting the engine
• Reduced power output
• Increased fuel consumption

Solution:

To ensure you don’t compromise performance, follow the replacement intervals recommended by the manufacturer.

Incorrect Spark Plug Gap

The spark plug gap is what separates the electrode tip and the ground strap. A wrong gap leads to bad combustion.

Symptoms:

• Engine knocking
• Hard starts
• Decreased throttle response

Solution:

• Use a gap tool to do this according to your vehicle’s specifications.

How Often to Change Spark Plugs in a V8

It should be realized that the interval depends on the biodegradable type of plug:

• Copper Spark Plugs: Every 20,000–30,000 miles
• Platinum Spark Plugs: Every 60,000 miles
• Iridium Spark Plugs: 80,000–100,000 Miles

In any case, replacing spark plugs will cost more with a V8 than other engine types and should be expected to cost even more with the V8, as double the number of parts and labor will be required for the process (6 spark plugs to replace for a V6 vs 16 for a V8).

How to Replace Spark Plugs on V8 Engines [DIY Guide]

Changing spark plugs in a V8 engine can be simple if you do these steps by the book.

Tools Required:

• Ratchet wrench with extension
• Spark plug socket
• Torque wrench
• (Optional): Anti-seize compound
• Dielectric grease

Step 1: Identify the location of the Spark Plugs

• Find the location of all 8 or 16 spark plugs. On some V8 engines, removing components from your intake is required to gain access.

Step 2: Get out old spark plugs

• Disconnect the ignition coil or the spark plug wire.
• Unscrew each plug using a spark plug socket.

Step 3: Check & Re-Gap: New Spark Plugs

• Inspect new plugs for defects
• Using a gap tool, adjust the spark plug gap according to manufacturer specifications.

Stage 4: Electrical Activity Inserting

• (Optional: Apply a thin layer of anti-seize compound (if suggested).
• Hand-start the plug and then tighten it with a torque wrench.

Step 5: Reattach Ignition Coils and Wiring

• Securely reattach the ignition components.

Top V8 Spark Plugs

After all, the right spark plugs can enhance the performance, durability, and fuel economy of an engine. Recommended options include:

• NGK Iridium IX – Best Performance for V8 engines
• Bosch Platinum Plus – Robust with high ignition force
• ACDelco Professional Platinum – GM replacement for V8 engines
• Denso Iridium TT – great durability and reliability

Final Thoughts

No matter if your V8 has 8 spark plugs or 16 spark plugs in total, it’s crucial that you maintain them so that your engine is operating at its best. If you better understand how spark plugs work, what signs of wear to look for, and what your car’s regular maintenance intervals are, you can keep your engine running well.

8 spark plugs are standard for the majority of GM, Chevrolet, and Cadillac V8 engines. However, with Dodge HEMI V8s, certain Mercedes-Benz models, and performance engines, a 16 spark plug count gets you even better combustion efficiency.

Understandably, this story alone won’t allow you to go 4,500 miles before having to visit a car doctor for a checkup, but knowledge is power when it comes to extending the life of your V8 engines. If you still confused with the V8 engine, you can buy a miyoo mini to have a check.