The 5.7 HEMI engine has a total of 16 spark plugs, with two spark plugs per cylinder. This dual-spark system enhances combustion efficiency, providing better performance, fuel economy, and reduced emissions.
If you’re driving a Chrysler, Dodge, or Jeep with a 5.7L HEMI engine, you might be wondering about the number of spark plugs this iconic engine requires. While most engines typically have one spark plug per cylinder, the 5.7L HEMI stands out with a unique dual-spark ignition system. This means there are a total of 16 spark plugs in the 5.7L HEMI engine—two spark plugs per cylinder. This configuration provides several benefits, including better combustion efficiency, more power, and improved fuel efficiency.
In this article, we will explain about the spark plug configuration of a 5.7L HEMI engine, including why it uses 16 spark plugs, how to replace them, and some essential maintenance tips.
Contents
What is a 5.7L HEMI Engine?
The 5.7L HEMI engine is a V8 engine developed by Chrysler. This engine, known for its power and reliability, is found in a variety of vehicles, including Dodge Chargers, Dodge Ram trucks, Chrysler 300C, and Jeep Grand Cherokees. The HEMI engine is renowned for its hemispherical combustion chamber design, which allows for better airflow and more power. The term “HEMI” refers to the shape of the combustion chamber, which is dome-shaped like a hemisphere.
The 5.7L HEMI engine features a dual-spark ignition system. Unlike a conventional engine, which uses one spark plug per cylinder, the 5.7L HEMI has two spark plugs per cylinder, resulting in a total of 16 spark plugs. This unique design is one of the reasons the 5.7L HEMI delivers improved performance, reduced emissions, and better fuel efficiency compared to conventional single-spark ignition systems.
How Many Spark Plugs Does a 5.7L HEMI Have?
As mentioned earlier, the 5.7L HEMI engine uses a total of 16 spark plugs. This is because the engine has 8 cylinders, and each cylinder is equipped with two spark plugs. In a traditional engine, one spark plug is used to ignite the air-fuel mixture in each cylinder, but the HEMI engine employs two spark plugs to ensure a more complete and efficient combustion process. This dual-spark system enhances performance and helps achieve smoother engine operation.
Why Does the 5.7L HEMI Use Two Spark Plugs Per Cylinder?
The primary reason for using two spark plugs per cylinder is to improve the combustion process. In an engine, the spark plug ignites the air-fuel mixture in the combustion chamber. When only one spark plug is used, it can sometimes result in uneven combustion, especially at higher engine speeds or under heavy load. By using two spark plugs, the HEMI engine ensures that the ignition process starts at two points in each cylinder, leading to a more uniform and complete burn of the air-fuel mixture.
This dual-spark ignition system provides several benefits, including:
- Improved Fuel Efficiency: A more complete burn of the air-fuel mixture leads to better fuel economy and fewer unburned hydrocarbons, resulting in fewer emissions.
- Enhanced Performance: The dual-spark system provides a more consistent and faster ignition, which translates to better power output and smoother engine operation.
- Reduced Emissions: More efficient combustion helps reduce harmful emissions, making the 5.7L HEMI more environmentally friendly.
- Improved Engine Longevity: With better combustion and less carbon buildup, the dual-spark system can help extend the life of your engine.
What Are the Spark Plugs Used in the 5.7L HEMI Engine?
The spark plugs used in the 5.7L HEMI engine are typically NGK LZFR5C-11 for models made after 2009. These spark plugs are designed to provide optimal performance for the HEMI’s unique ignition system. The recommended spark plug gap for the 5.7L HEMI is 0.043 inches. It is important to use the correct spark plugs and replace them at regular intervals to maintain engine performance.
How to Replace the Spark Plugs in a 5.7L HEMI
Replacing the spark plugs in your 5.7L HEMI engine might sound intimidating, but with the right tools and instructions, it’s a task you can tackle yourself. Here’s a detailed, step-by-step guide on how to do it:
Tools You’ll Need:
- Socket wrench and extension bar
- Torque wrench
- Spark plug socket
- Dielectric grease
- NGK LZFR5C-11 spark plugs (or the correct ones for your vehicle)
- Ratchet wrench and spark plug boot puller (optional)
- Anti-seize lubricant (optional)
Step 1: Preparation
Before you begin, make sure the engine is cool. Working on a hot engine can cause burns or accidents. Also, gather all the necessary tools and materials. You’ll also want to disconnect the vehicle’s battery to prevent any electrical mishaps while working on the ignition system.
Step 2: Remove Engine Covers
Most HEMI engines have plastic engine covers that need to be removed before you can access the ignition coils. Use a socket wrench or screwdriver to carefully remove these covers. Keep them in a safe place for reinstallation.
Step 3: Remove the Ignition Coils
The 5.7L HEMI engine has an ignition coil for each spark plug. These coils are usually held in place by bolts. Use a wrench to remove the bolts, then gently pull the ignition coils off each spark plug. It’s a good idea to label the coils so that you can reassemble them in the correct order.
Step 4: Remove the Old Spark Plugs
Now it’s time to remove the old spark plugs. Using your spark plug socket and extension bar, carefully loosen and remove each spark plug. Be sure to keep track of the old spark plugs for reference in case you need to inspect them for wear or damage.
Step 5: Install the New Spark Plugs
Before installing the new spark plugs, apply a small amount of dielectric grease to the inside of the coil boots. This helps prevent misfires and ensures a good connection. Next, carefully install each new spark plug into the cylinder head by hand, ensuring it threads in smoothly.
Once the spark plugs are hand-tight, use a torque wrench to tighten them to the manufacturer’s recommended torque specification. Over-tightening or under-tightening can lead to engine damage, so be sure to follow the correct specs.
Step 6: Reinstall the Ignition Coils
After the spark plugs are installed, place the ignition coils back over the spark plugs and secure them with the bolts. Reconnect the coil wiring, making sure everything is snug and properly connected.
Step 7: Reassemble the Engine
Replace any engine covers or components you removed during the process. Double-check that everything is reassembled correctly and that no tools are left behind in the engine bay.
Step 8: Test the Engine
Reconnect the battery and start the engine. Listen for any unusual sounds or vibrations. The engine should run smoothly with no misfires or rough idling. If everything is in order, you’ve successfully replaced the spark plugs in your 5.7L HEMI!
Maintenance Tips for the 5.7L HEMI Spark Plugs
To keep the 5.7L HEMI running like new, regular spark plug maintenance is essential. Here are a few tips to help you maintain your spark plugs and ensure optimal engine performance:
- Check Spark Plugs Regularly: Inspect the spark plugs every 30,000 miles to check for wear or carbon buildup. If you notice signs of damage, it’s time to replace them.
- Use Quality Parts: Always use spark plugs that meet the manufacturer’s specifications. Using the wrong type of spark plug can lead to poor engine performance and even damage.
- Torque to Spec: Always tighten the spark plugs to the manufacturer’s recommended torque specification to avoid damaging the cylinder head or spark plugs.
- Monitor Engine Performance: Keep an eye on how your engine is running. If you notice misfires, poor acceleration, or rough idling, inspect your spark plugs as they could be the source of the problem.
Frequently Asked Questions
Here are some FAQs about the spark plugs in a 5.7 Hemi –
1. Why does the 5.7L HEMI have two spark plugs per cylinder?
The 5.7L HEMI uses two spark plugs per cylinder to improve combustion efficiency. By firing two spark plugs per cylinder, the air-fuel mixture burns more completely, which leads to better performance, fuel efficiency, and reduced emissions.
2. How often should I replace the spark plugs in my 5.7L HEMI?
It is generally recommended to replace the spark plugs in a 5.7L HEMI every 30,000 miles. However, it’s a good idea to check them periodically for signs of wear, especially if you notice performance issues.
3. Can I replace the spark plugs myself?
Yes, replacing the spark plugs in a 5.7L HEMI can be done by anyone with basic mechanical skills and the right tools. Just follow the steps carefully and make sure you torque the spark plugs to the proper specifications.
4. What type of spark plugs should I use for my 5.7L HEMI?
The recommended spark plugs for the 5.7L HEMI are NGK LZFR5C-11. Always check your owner’s manual to confirm the exact part number for your specific model and year.
5. What happens if I don’t replace my spark plugs on time?
If spark plugs aren’t replaced on time, they can cause misfires, rough idling, poor acceleration, and reduced fuel efficiency. Over time, worn spark plugs can also damage other engine components, leading to costly repairs.
Conclusion
Knowing how many spark plugs the 5.7L HEMI engine has, and why it uses two per cylinder, is essential for proper maintenance. This dual-spark system improves combustion, leading to better performance, fuel efficiency, and lower emissions. Regular spark plug maintenance ensures your engine runs smoothly and lasts longer. If you’re ready to take on the task of replacing your spark plugs, follow the steps outlined above, and you’ll be good to go! Happy driving!