Chevy Geek

LS Firing Order and Cylinder Numbers (With Diagrams)

The LS engine is a family of V8 engines that was introduced by General Motors in 1997. It is based on the small-block Chevy engine, but it has been redesigned with a number of improvements, including a new cylinder head design, a more efficient intake manifold, and a lighter crankshaft.

LS Firing Order

The firing order of a Chevy or GM LS engine is 1-8-7-2-6-5-4-3. This means that the first cylinder fires, followed by the 8th cylinder, then the 7th, and so on. The firing order is important because it ensures that the cylinders fire in a specific sequence that optimizes the power output and efficiency of the engine.

The idea behind its creation was to increase the Chevy 350’s power without compromising its small-block form (In fact, the LS and 350 engines share external dimensions). In addition to that, the LS engine had to satisfy modern economic and emission standards.

In this article, we’ll discuss the different LS firing order and cylinder numbers. We will also discuss the importance of these factors and how they can affect the performance and drivability of the engine.

LS Firing Order Diagram

ls firing order

The firing order is determined by the order in which the spark plugs fire. The spark plugs are located in the combustion chambers of the cylinders. When the spark plugs fire, they ignite the air-fuel mixture in the combustion chamber, which causes the cylinder to explode.

The explosion forces the piston down, which rotates the crankshaft. The crankshaft then turns the camshaft, which opens and closes the valves. This process repeats itself over and over again, creating a smooth, continuous power output.

The firing order for the Chevy LS engine is designed to minimize vibration and optimize power output. The specific sequence of the firing order ensures that all of the cylinders are firing at evenly spaced intervals. This helps to smooth out the power output of the engine and reduce vibration.

All stock LS Engines have the 1-8-7-2-6-5-4-3 firing order. It’s an upgrade on the 1-8-4-3-6-5-7-2 firing order of the traditional Chevy Small/Big Block Engines.

4/7 Swap Firing Order

Changing your engine’s firing order from the traditional version to the improved LS order is possible. The procedure is called “The 4/7 Swap.” You should only proceed to do so after consulting experienced mechanics. They will tell you whether or not it’s worth it, depending on your needs.

LS Cylinder Numbers

Different manufacturers number their cylinders differently. In the LS Engine, we have four cylinders on the right of the block and four others on the left. “The Fold Method” is the most commonly used cylinder numbering system.

You have to stand in front of the vehicle and face it head-on to get it right. On the driver’s side, we have the 1-3-5-7 cylinders. Cylinder #1 is the closest to you, and cylinder #7 is the furthest. On the passenger side, we have the 2-4-6-8 cylinders. Similarly, cylinder #2 is the closest to you, and cylinder #8 is the furthest.

ls cylinder numbers

The cylinder numbers are important for identification and troubleshooting purposes. If you are working on a Chevy LS engine, it is important to know the cylinder numbers so that you can properly identify the cylinders and troubleshoot any problems.

4.8 LS Firing Order and Cylinder Numbers

4.8 LS Engine Overview

The 4.8 LS Engine is also known as The Vortec 4800 (or 4.8L Vortec). Some people even refer to it as the LR4. It was first introduced into the market in 1999. Historically, it’s among the first truck engines of the LS Generation III. It remained in production until 2007.

As expected of LS Engines, the LR4 is a solid and durable masterpiece still usable today.

The 4.8 LS Engine is also compatible with upgrades like superchargers, turbos, high-flow cylinder heads, cams, nitrous oxide, and intake systems. A well-modified 4.8 LS engine can generate up to 1000 horsepower.

The 4.8 LS Engine was installed in several vehicle models, including the Chevrolet Silverado 1500 (1999 to 2006), the Chevrolet Tahoe (2000 to 2006), and the Chevrolet Express (2003 to 2006).

4.8 LS Firing Order

Like all other LS Engines, the 4.8 Engine has the 1-8-7-2-6-5-4-3 firing order in the clockwise direction.

ls 4.8 firing order and cylinder number

4.8 LS Cylinder Numbers

It follows the “Fold” cylinder numbering system. Therefore, when facing your vehicle from the front, cylinder numbers 1-3-5-7 are on the driver’s side. Cylinder #1 is closest to you. On the hand, cylinder numbers 2-4-6-8 are on the passenger’s side, with cylinder #2 closest to you.

Chevy 5.3 (5.3 Vortec) Firing Order and Cylinder Numbers

5.3 LS Engine Overview

The 5.3 LS Engine is part of the Gen III Small Block Series. It’s also referred to as the Vortec 5300 or the LM7/L59/LM4. Like the 4.8L engine, it reigned from 1999 to 2007.

According to some auto enthusiasts, it was the most robust and popular engine across Gen III, IV, and V LS Engines. Even today, an old 5.3 LS Engine in a salvage yard can serve you efficiently. Some units will continue working well even after hitting the 100,000-mile mark.

Like all other LS Engines, it’s compatible with upgrades like turbos, superchargers, intake systems, high-flow cylinder heads, and nitrous oxide.

In its tenure, it was an option in several classics, including the Chevrolet Silverado (1999 to 2007), the Chevrolet Tahoe (1999 to 2006), the Chevrolet Avalanche (2002 to 2006), and Chevrolet Express (2003 to 2007).

5.3 LS Firing Order

The 5.3 firing order is 1-8-7-2-6-5-4-3, in the clockwise direction.

ls 5.3 firing order and cylinder number

5.3 LS Cylinder Numbers

It uses the fold cylinder numbering system. As you look at your vehicle from the front, cylinders 1-3-5-7 are on the driver’s side. On the hand, cylinders 2-4-6-8 are on the passenger’s side.

Chevy LS 6.0 Firing Order and Cylinder Numbers

6.0 LS Engine Overview

The Gen III 6.0 LS Engine is also called the LQ4 or the Vortec 6000. It’s a truck engine that was popular between 1999 and 2007.

They used this engine in several vehicle models, including the Chevrolet Suburban (1999 to 2004), the Chevrolet Silverado 2500 (1999 to 2004), the Chevrolet Silverado 1500HD (2001 to 2007), the Chevrolet Silverado 3500 (2001 to 2007), and the Chevrolet Express (2003 to 2007).

Like its other LS Engines, it performs well with upgrades like superchargers, turbos, intake systems, cams, high flow cylinder heads, etc.

6.0 LS Firing Order

The 6.0 LS Engine has the standard 1-8-7-2-6-5-4-3 LS firing order in the clockwise direction. 

ls 6.0 firing order and cylinder number

6.0 LS Cylinder Numbers

The 6.0 LS Engine follows the Fold cylinder numbering system. As you face your vehicle from the front, the cylinders 1-3-5-7 are on the driver’s side. Meanwhile, the cylinders 2-4-6-8 are on the passenger side. In that view, cylinders 1 and 2 are closest to you and opposite each other.

GM 6.2 Firing Order and Cylinder Numbers

6.2 LS Engine Overview

The 6.2 LS Engine is a small block Gen IV engine, also known as the L92 or the Vortec 6200. With a more robust casting and larger bores, it succeeded the 6.0 LS2. It’s also compatible with upgrades like turbos, superchargers, cams, etc.

Throughout its tenure from 2000 to 2017, it was featured in several GM luxury trucks and SUVs. The most popular vehicle models of the time included the Chevrolet Grand Sport (2008 to 2013), the Chevrolet Corvette W/Open Exhaust (2008 to 2013), the Chevrolet Camaro SS Coupe and Convertible (2009 to 2015), and the Chevrolet SS (2015 to 2017).

6.2 LS Firing Order

The 6.2 LS Engine firing order is 1-8-7-2-6-5-4-3 (clockwise direction).

ls 6.2 firing order and cylinder number

6.2 LS Cylinder Numbers

Its cylinder numbering follows “The Fold Method.” As you face your vehicle from the front, all odd cylinder numbers 1-3-5-7 are on the driver’s side. On the other hand (left), we have all even cylinder numbers 2-4-6-8.

LS Firing Order Vs SBC Firing Order

All LS, Small Block, and Big Block engines have the same cylinder numbers. They all adhere to the Fold Cylinder Numbering System.

Therefore, as you face your vehicle from the front, odd cylinders 1-3-5-7 are on the driver’s side. On the hand, even cylinders 2-4-6-8 are on the passenger’s side. Cylinders #1 and #2 are closest to you and opposite each other.

LS Firing Order Vs. SBC: Which is better?

The firing order of SBC and BBC is 1-8-4-3-6-5-7-2. On the other hand, LS Engines have the new 1-8-7-2-6-5-4-3 firing order.

After countless computer simulations and engine tests, GM came up with the LS firing order. It is better than the firing order of SBC and the BBC.

LS Firing Order vs SBC Firing Order Diagram

ls firing order vs sbc/bbc firing order

Below are the pros and cons of the LS firing order.

Pros

  • Reduces crash-shaft irregularities, thus increasing the engine’s durability.
  • Comes with a power boost.
  • It offers better heat management.
  • It allows for harmonious engine operation that reduces vibrations and tears.
  • Offers enhanced torque.

Cons

  • It requires a considerable amount of money and effort to swap a V8 engine from the traditional to the LS firing order. At times, it’s not worth it.

Gen III, IV, and V Chevy LS Engines

Gen III

The first Generation III LS Engine made its debut in 1997. It was first featured in the famous 5th Generation Chevrolet Corvette C5. It was an all-aluminum V8 masterpiece that built upon the popularity of the Chevy 350 Small Block.

During its reign from 1999 to 2007, many different Gen III LS engines graced the market, including the LS1, LS6, LR4, LM7, L59, LM4, and L33. They had varying displacements of 4806cc, 5327cc, 5665cc, and 5967cc.

Gen III LS Engines were available in popular vehicle models like the Chevrolet Silverado, Chevrolet Tahoe, Chevrolet Express, Chevrolet Avalanche, etc.

Gen IV

Generation IV LS Engines ruled the marketplace from 2005 to 2020. They succeeded Gen III Engines by offering higher displacement figures of 7,441cc. Unlike Gen III engines that were “rigid,” Gen IV LS Engines had the “Displacement On-Demand Technology”. It allowed users to deactivate any other cylinder in the firing order.

Gen IV’s engine roster included the LS2, L76, L98, L77, LY6, L96, LFA, and LZ1. These engines were the options across many vehicle models like the Chevrolet Silverado HD, Chevrolet Express, Chevrolet Suburban 3/4 ton, Chevrolet Impala SS, Chevrolet Camaro SS, etc.

Gen V

The Generation V LS Engines broke into the market in 2013 and are still in production. Even though they are structurally similar to the Gen III and IV engines, they come with significant internal upgrades.

For example, their cooling systems and new cylinders are much better. The popular LT1 engine is also part of Gen V’s roster. It debuted in late 2012 inside the Chevrolet Corvette C7.

Examples of other Chevy vehicles that rocked Gen V LS Engines include the Camaro SS, the Corvette C8, the Camaro ZL1, Silverado, Tahoe, Suburban, and the Corvette Z06.

Read more: 1999-2022 Chevy/GMC 5.3 Oil Capacity & Oil Type Free Lookup

Conclusion

In conclusion, the LS engine has a standard firing order of 1-8-7-2-6-5-4-3. The is applicable to any of the Chevy or GM 4.8, 5.3, 6.0, or 6.2 engines. However, there are some variations to this firing order, depending on the specific engine application. For example, some LS engines have a 4-7 swap, which means that cylinders 4 and 7 are swapped in the firing order. This can be done to improve the performance or drivability of the engine.

The cylinder numbers on an LS engine are also important. The frontmost cylinder is usually numbered 1, and the numbering continues sequentially from there. However, some LS engines have a different cylinder numbering scheme, such as the 5.3L Vortec engine, which has its cylinders numbered 1, 3, 5, 7 on the driver’s side and 2, 4, 6, 8 on the passenger side.

The firing order and cylinder numbers of an LS engine are important factors that can affect its performance and drivability. It is important to understand these factors when working on or modifying an LS engine and we hope this guide helped answer your questions!

Author

  • Randy Worner

    My name is Randy Worner and I am the founder of chevygeek.com. I have been working on cars and trucks for almost 45 years. For the last 36 years I have taught Automotive / Diesel Technology classes for UTI, Snap On Tools, Chrysler, Pepboys, Lone Star College, NAPA and TBC Corporation. I also own a technical writing company known as Supreme Technical Services. It is ASE Gold Seal certified and Blue Seal Certified Author of auto/truck repair information.

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6 thoughts on “LS Firing Order and Cylinder Numbers (With Diagrams)”

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  2. Oops!
    Somebody should proofread your articles before they are posted.

    At the beginning (2nd paragraph) of the article you state that the LS firing order is 1-8-7-6-5-4-3-2, then you show a diagram with 1 8 7 2 6 5 4 3.

    FYI,
    Scott

    1. Good catch! We will be going over some of our more popular articles and making some edits and updates soon. Thank you for pointing out this error; we appreciate useful feedback.

      -Dave-

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