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Duramax 6.6 Firing Order – With Diagrams!

When it comes to diesel engines, the Duramax 6.6 is a popular choice for truck enthusiasts. One important aspect of this engine is its firing order, which refers to the sequence in which the cylinders fire. Getting the firing order right is critical for the engine to function properly and efficiently.

Duramax 6.6 Firing Order

The firing order for the Duramax 6.6 is 1-2-7-8-4-5-6-3. This sequence determines the order in which fuel is injected and ignited in the cylinders.

This means that the first cylinder to fire is number one, followed by cylinders two, seven, eight, four, five, six, and three in that order.

Duramax Cylinder Order

The cylinders on a Duramax engine are numbered from front to back, starting with the number one cylinder. The number one cylinder on an inline Duramax engine is located close to the timing cover at the front side of the engine.

If the engine is left completely stock, there isn’t much of a problem with this firing order. However, the crankshaft on the 6.6-liter Duramax is known for being on the weaker side. This means that if you plan on upgrading your engine with performance parts, you may need to consider upgrading your crankshaft as well to handle the increased power.

It is also important to note that a misfire in any of the cylinders can cause a variety of issues, including decreased engine performance, reduced fuel efficiency, and increased emissions.

6.6 Duramax Cylinder Numbers

The 6.6L Duramax V8 diesel engine used in Chevrolet and GMC trucks from 2001-present has 8 cylinders numbered from 1-8. Cylinders 1, 3, 5, and 7 are located on the passenger side of the engine. Cylinders 2, 4, 6, and 8 are located on the driver’s side.

Duramax Cylinder Location

Counting from the front of the engine to the back, cylinder 1 is located at the front-most part of the engine on the passenger side. Cylinder 8 is located at the rear-most part of the engine on the driver’s side.

The firing order of the Duramax engine is 1-2-7-8-4-5-6-3. So cylinder 1 fires first, then cylinder 2, then cylinder 7, and so on following that firing sequence.

To help remember the firing order sequence, you can use the acronym “I Have Very Little Faith In My Engine.” Each letter corresponds to a cylinder in the firing order sequence.

LetterCylinder
I1
H2
V7
L8
F4
I5
L6
M3

Duramax 6.6 Cylinder Layout

standard drama 6.6L firing order

Alternative 6.6 Duramax Firing Order

While the stock firing order works well for most applications, it can cause issues when the engine is modified for higher performance. In the 6.6-liter Duramax, it has a reputation for its crankshaft being on the weaker side. As a result, increasing the power output can put additional stress on it.

One way to address this issue is to modify the firing order.

By changing the firing order, it is possible to relieve stress on the front portion of the crankshaft in higher performance applications.

For example, the new camshaft design changes the firing order to 1-5-6-3-4-2-7-8. This change can help to improve engine performance and reliability.

LBZ Duramax

The LBZ Duramax engine, used in Chevrolet and GMC trucks from 2006-2007, has a standard firing order of 1-2-7-8-4-5-6-3. However, some owners choose to install the alternate firing order camshaft of 1-5-6-3-4-2-7-8 to improve balance and reduce vibration.

Alternate Firing Camshaft Diagram for Duramax 6.6

Frequently Asked Questions

What are the cylinder numbers for a 2015 Duramax?

The Duramax cylinder numbers are 8 in total. The 2, 4, 6, and 8 cylinders of the Duramax are placed on the driver’s side, while the 1, 3, 5, and 7 cylinder numbers are placed on the passenger’s side. This cylinder numbering is important to remember when diagnosing engine problems or doing any maintenance on your Duramax engine.

What is the cylinder layout for a Duramax L5P?

The Duramax L5P has a V8 engine configuration, with each bank of cylinders having four cylinders. The cylinders are arranged in a V shape, with the cylinders tilted at an angle of 90 degrees. The L5P engine has a bore size of 4.06 inches and a stroke of 3.90 inches, resulting in a total displacement of 6.6 liters.

Which cylinder is number 2 on a Duramax?

The number 2 cylinder on a Duramax engine is located on the driver’s side of the engine. It is the second cylinder from the front of the engine on the driver’s side. This cylinder numbering is important to remember when diagnosing engine problems or doing any maintenance on your Duramax engine.

Why do LMM cranks break?

The LMM Duramax engine is known for crankshaft failures due to the high stresses placed on the crankshaft by the engine’s power output. The factory crankshaft is known to be weaker than aftermarket options, and the engine’s harmonic vibrations can cause the crankshaft to fail prematurely. Upgrading to a stronger aftermarket crankshaft is recommended for those looking to increase the power output of their LMM Duramax engine.

Author

  • Randy

    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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