How Many Spark Plugs In A V8 Engine?

Have you thought about replacing your spark plugs and wondered how many spark plugs are in your V8 engine? This article is designed to get you up to speed with how many spark plugs your V8 engine will typically have as well as inform you how to replace the spark plugs on your engine if you are interested in doing that process yourself.

The majority of engines will have one spark plug per cylinder. A V8 engine has 8 cylinders so it will have 8 spark plugs. Hemi V8 engines use two spark plugs per cylinder which means 16 spark plugs in total.

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How can you tell how many spark plugs your V8 has? It really depends on who made your car. For a list of cars and how many spark plugs each car has check out my table below.

How Many Spark Plugs Does My V8 Have?

Most engines are able to get the job done with just one spark plug but there are some vehicle manufacturers that have started designing their engines with two spark plugs per cylinder. These engines are called twin spark or dual spark engines.

Below is a table showing various V8 cars and trucks that show how many sparks plugs each engine would take. Mercedes and Chrysler’s engines are the most common engines that would use 16 spark plugs.

VehicleNumber of Spark Plugs
2015 Ford Mustang GT8
2017 Chevrolet Camaro SS8
2003 Mercedes CL55 AMG16
2006 Dodge Charger R/T16
2008 Chevrolet Corvette8
2016 Ford F1508
2013 Dodge Ram 5.7L16
2011 Jeep Grand Cherokee 5.7L16
2008 BMW M38
2009 Pontiac GTO8

What is a Spark Plug?

A spark plug sits in the cylinder of your engine and produces a spark to ignite the air and gas mixture that is compressed by the pistons of your engine. Once the air and fuel mixture is ignited this produces an explosion in the cylinder wall of your engine that then forces the piston down and produces the kinetic energy needed to propel you forward.

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Dual Ignition and Twin Spark Engines

There are a couple of vehicle manufacturers that I know of that have started making their engines with a twin spark system which uses two spark plugs per engine cylinder. Twin spark engines started to be created because of the modern emissions standards that keep changing requiring innovative solutions by auto manufacturers that lead to the twin spark design.

The benefits of using a twin spark design are that with a twin spark design the air and fuel mixture should be completely burnt. With two spark plugs in each cylinder wall, this increases the speed at which the air and fuel mixture is completely combusted as well as reducing the likelihood of the engine backfiring or creating engine knock.

The downsides of using a twin spark system are that you have to pay for two spark plugs for each cylinder which will increase the cost of replacing your spark plugs on your engine by double. Spark plugs are somewhat cheap when compared to other maintenance items on your vehicle but if you have to buy 16 of them that cost is going to start to add up.

Common Engines with Twin Spark Engines

The two most common engines that use this technology are going to be made from Mercedes and Dodge. Mercedes is known for over-engineering things when it comes to making their vehicles so it’s no surprise when they develop their engines using two spark plugs. But the Chrysler HEMI design has been around since the ’50s.

Dodge started using this technology on their 5.7L HEMI V8 engines and because they use standard spark plugs in the engine from the factory the recommended replacement is at 30,000 miles.

How many spark plugs does a 5.7 HEMI have? The 5.7L HEMI V8 uses two spark plugs per cylinder so it uses 16 spark plugs overall. This means replacing the spark plugs on a HEMI 5.7L V8 will cost twice as much as a typical V8 engine.

Related Questions

How Many Spark Plugs In a V6? The vast majority of V6 engines are going to use 6 spark plugs, one spark plug per cylinder. However, there are some engines from European manufacturers that use two spark plugs per cylinder. In twin spark engines they require the use of 12 spark plugs or two per each cylinder.

Mercedes Benz also made twin spark engines but they didn’t really call them twin spark engines. Alfa Romeo coined the term twin spark engines for their V6 engines that they developed with two spark plugs per cylinder.

Twin spark engines were created to help burn the air and fuel mixture by creating two sparks in the engine cylinders. The theory is that two sparks are better than one and more fuel would be burnt off if two spark plugs fired at the same time.

If you have a V6 engine I also wrote a similar article outlining how many spark plugs are typical in a V6 engine.

What Are The Symptoms of Bad Spark Plugs? Symptoms of bad spark plugs can include but are not limited to a car that has trouble starting, your car keeps dying after temporarily starting, and smoke coming out of your exhaust.

If your spark plugs are going bad they may not be able to do their main job of burning the air and fuel mixture in your engine cylinders. When the fuel in your engine cylinders is not being fully burnt off in the engine cylinders then that excess fuel will be sent out through your exhaust which could cause smoke to come out of your exhaust. Say that your car is having trouble running or is running rough. This could also be a sign that your spark plugs need to be replaced.

Another sign that your spark plugs may need to be replaced is engine hesitation. When you press on the accelerator and the engine doesn’t want to propel you forward it may be having issues with the spark plugs. If you check your spark plugs and they are black they likely need to be replaced.

If you pull out your spark plugs and find that they are black and wet you may want to check out this other article I wrote about what to do if your spark plugs are black and wet.

How Often Do You Need to Change Spark Plugs? If you are concerned that your spark plugs are old and may need to be replaced you can consult your owners manual to find out how often they recommend your spark plugs be replaced.

If you do not have an owners manual in your car you can also find out the spark plug change interval by looking up that information online.

Say that you just bought a used car and you are unsure of the last time your spark plugs have been changed. In that case, I would go ahead and replace them out of precaution just in case they have been in the engine for a long time. Spark plugs are relatively inexpensive and can greatly impact the performance of your engine.

Once you have replaced your spark plugs you could then note that in your records for your vehicle and then replace the spark plugs down the line based on your manufacturers recommended change interval.

How to Change Your Spark Plugs

If you need to change your spark plugs on your engine it’s usually not too difficult depending on how many cylinders your engine has and how much room there is in your engine bay. If the engine expands most of the room in the engine bay it is going to be tough to be able to get your hands around to the sides of your engine bay to be able to remove your spark plugs.

With smaller inline four-cylinder engines the spark plugs are going to be easily accessible and will be on the top of the engine. With V6 or V8 engines, the cylinders are aligned in a V shape so the spark plugs will be on the side of your engine.

How to Replace Spark Plugs

You would first need to purchase your replacement spark plugs either online or at another local parts store to have on hand to be able to install in your engine. If your engine is like most other engines it should just take one spark plug per cylinder, so if you have a four-cylinder car it should take four spark plugs.

You would need to get access to your engine to be able to replace your spark plugs so if your engine comes with an engine cover that would cover up your spark plugs you would need to first remove that so that you could gain access to your engine.

If your car is older then it should still be using spark plug wires and a distributor cap to be able to produce the electricity to shoot into your cylinder to be able to provide the spark to combust the air/fuel mixture in your cylinder walls.

Some newer cars will use coil packs which are installed on each cylinder which will need to be removed to allow you access to the old spark plugs to be able to remove them from your engine.

With coil packs, they are designed to be a newer technology that can produce the energy to send a spark to the combustion chamber from each coil pack installed on the engine. A distributor cap is designed to produce that electricity in the distributor cap and then have that electricity fed to the individual spark plugs using spark plug wires.

Spark Plug Removal

To be able to remove your old spark plugs from your engine you will need to be able to loosen the spark plugs from within your cylinder and be able to pull them from your engine.

The good news is that they make tools specifically designed for spark plug removal that allow you to insert one end of the tool into the cylinder wall to be able to loosen the spark plug, the tool then features a magnet built into the base of the tool to allow you to remove the spark plug from your engine cylinder using the magnet to pull it up and out of the cylinder wall.

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If you are interested in purchasing this spark plug socket tool off of Amazon I’ve included a link to on here.
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After you have removed your old spark plugs you are now ready to reinstall your new spark plugs. Some spark plugs will call for using anti-seize on the threads of the spark plugs to be able to remove them easier the next time around but some may already have some applied or don’t need any applied when you go to install them.

All spark plugs should have dielectric grease applied to the nipple portion of the spark plugs to allow the spark plug wire or coil pack to be able to be removed easily from the tip of your spark plugs when they need to be replaced again. If you don’t apply dielectric grease to your spark plugs sometimes the boot of the spark plug wires will get stuck and won’t allow you to easily remove the spark plug wire from the spark plug.

Spark Plug Gap

Most spark plug manufacturers will already have the spark plugs that they make at the correct gap between the pin and the electric diode but it’s a good idea to make sure that they are properly gapped before you install them in your engine.

You never know if your spark plugs could have been damaged during the shipping process and checking the gap yourself before you install them will make sure that they are properly gapped.

You can buy a spark plug gap tool if you do not own one that will allow you to measure the gap between your electric diode and the tip of your spark plug to make sure that it is not too wide or too narrow.

I’ve linked to one of these spark plug gap gauges so that you can buy one online or find a similar one at your auto parts store. Check out this link to a spark plug gauge gap on Amazon here: Lisle 67870 Spark Plug Gauge Gap

Install Your New Spark Plugs

You will then want to go ahead and install your new spark plugs into your engine cylinders. If you have a twin-engine you would want to make sure that you replace both spark plugs in each cylinder and not just one per cylinder. If you just replaced one spark plug per cylinder in a twin spark engine that could cause the engine to run rough and idle badly.

Once you have your new spark plugs installed in your engine you can now go ahead and reinstall your spark plug wires or coil packs back onto your engine. Once you are done with replacing all of the spark plugs on your engine you should go ahead and test out that your vehicle still runs properly by starting up your engine to make sure it still starts.

If your engine still starts when you go to fire it up and sounds good you should go ahead and check to see if you see any check engine lights. Check to make sure you don’t see any check engine lights and your engine sounds like it is running fine you should be good to go.

I’ve included a video on Youtube on how to replace your spark plugs on your vehicle I’ve linked a spark plug replacement video so that you can see how the process is done in a video format.

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How Many Spark Plugs In A V8 – Conclusion

Hopefully, now you understand how many spark plugs are in a V8 engine. Most V8 engines are going to have 8 spark plugs or one spark plug per engine cylinder. Some newer engines such as from Mercedes or Dodge have twin spark engines which means that they have two spark plugs per each cylinder or 16 spark plugs in total.

You would always want to replace all of your spark plugs at the same time and not just replace one spark plug or a few at a time. If you didn’t replace all of your spark plugs at the same time this could cause your engine to run rough and have a rough idle.