Firing Order for Duramax 6.6 [With Diagram]

The Duramax is one of the most used and popular engines used in many vehicles. It provides great power output thanks to the impressive 6.6-cylinder layout and firing order. 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.

The Duramax was first introduced in 2001 and was developed by DMAX. The original firing order of the 6.6 Duramax was 1-2-7-8-4-5-6-3. However, the Duramax firing order changed due to the introduction of a new camshaft design.

Duramax 6.6 firing order

  • Firing order for Duramax 6.6 is 1-2-7-8-4-5-6-3

Explanation of 6.6 Duramax engine

The original l5p duramax firing order was 1-2-7-8-4-5-6-3. What a firing order refers to is the combustion sequence of the cylinders in an engine. In gas engines, it describes the order of spark plug performance, and in diesel engines, it describes the order of fuel injection.

The firing order of the stock Duramax means that the first cylinder will be ignited first and then the second and then the seventh and so on. The Duramax firing order changed to 1-5-6-3-4-2-7-8 which solved the weak crankshaft issue of the Duramax.

Torque Specifications

Intake manifold bolts23-25 ft-lbs
Oil pump bolts23-28 ft-lbs
Cam bolts40-45 ft-lbs.
Cam thrust plate bolts8-10 ft-lbs
Harmonic damper bolt70-90 ft-lbs
Flywheel / flex-plate bolts75-85 ft-lbs
Pressure plate bolts35 ft-lbs.

Where is the number one cylinder on a Duramax?

The number one cylinder on an inline Duramax engine is located close to the timing cover at the front side of the engine.

What causes Duramax to break the crank?

Excessive RPM and large external counterweight are on of the main reason that causes the crank of the Duramax engine to break. A factory firing order is also known to impose stress on the crank which can also cause it to become weak and break.

Check out 1342 Firing Order

Does a Duramax have a camera?

Yes, the Duramax engines do have a camera. The Duramax engines respond to alternate firing camshafts very well. This is because the right camshaft increases the heat flow of the Duramax because of the high-flow aluminum heads.

What years of Duramax to avoid?

It is best to avoid the Duramax years between 2001 and 2010. The Duramax has gotten better and better ever since 2010. If you are looking to get a Duramax, you should get one of the newer releases.

Firing Order Applies to:

Vehicle Engine Firing Order
400 Chevy V8 1-8-4-3-6-5-7-2
454 Chevy V8 1-8-4-3-6-5-7-2
Chevrolet V8 (Various) 1-8-4-3-6-5-7-2
Silverado V8 (Depends) Depends on Engine
GMC V8 (Various) Depends on Engine
Sierra V8 (Depends) Depends on Engine
Jake Mayock