Quick Identifier:
LB7s were used from 2001-2004. Ways to identify this engine:
– Injectors and injector harnesses under the valve covers
– The FICM (fuel injection control module) will be located on the front of the passenger side valve cover
The LB7 Duramax was first introduced in 2001 and produced until 2004. The 32 valve, V8 design utilizes a high pressure common rail direct injection system. Due to the lack of emission equipment, the LB7 is considered one of the most sought after Duramax’s built, obtaining the best fuel mileage and having the simplest design.
| Years Produced | 2001 – 2004 |
| Displacement | 402 cubic inches, 6.6 liters |
| Configuration | 90 degree V8 |
| Compression Ratio | 17.5:1 |
| Bore | 4.06 inches |
| Stroke | 3.90 inches |
| Aspiration | • Turbocharger • air to air intercooler • Maximum boost: 20 psi |
| Valvetrain | OHV, 4 valves per cylinder |
| Injection | • Direct injection • Bosch high pressure common rail, CP3 injection pump • 23,000 psi max injection pressure |
| Horsepower | • 235 hp @ 2,700 RPM (2001) • 300 hp @ 3,100 RPM (2004) |
| Torque | • 500 lb-ft @ 1,600 RPM (2001) • 520 lb-ft @ 1,800 RPM(2004) |
Quick Identifier:
LLYs were used from 2004.5-2005. Ways to identify this engine:
– Exposed injectors and injector harnesses
– Variable vane turbo charger
– Has FICM (fuel injection control module) on the passenger side valve cover
– EGR cooler is cylindrical
The Duramax LLY was introduced in 2004 to replace the popular LB7. Like the LB7, the LLY utilizes a high pressure common rail direct injection system. The LLY was General Motors’ first attemp at implementing emission controls on a diesel engine to meet stricter emissions requirements in the future. The LLY adopted a variable geometry turbocharger (VGT) and exhaust gas recirculation (EGR) system to help reduce emissions. Huge changes to the LLY debuted in 2005, but the engines were mechanically identical.
| Years Produced | 2004.5 – 2005 |
| Displacement | 403 cubic inches, 6.6 liters |
| Configuration | 90 degree V8 |
| Compression Ratio | 17.5:1 (16.8:1 in 2006) |
| Bore | 4.06 inches |
| Stroke | 3.90 inches |
| Aspiration | • Garrett variable geometry turbocharger (VGT) • air to air intercooler |
| Valvetrain | OHV, 4 valves per cylinder |
| Injection | • Direct injection • Bosch high pressure common rail, CP3 injection pump • 23,000 psi max injection pressure |
| Horsepower | • 310 hp @ 3,000 RPM • 310 hp @ 3,000 RPM (2006) |
| Torque | • 520 lb-ft @ 1,600 RPM • 605 lb-ft @ 1,600 RPM (2006) |
Quick Identifier:
LBZs were used from 2006-2007. Ways to identify this engine:
– Exposed injectors and injector harnesses
– Variable vane turbo charger
– No FICM (fuel injection control module) on the passenger side valve cover
– EGR cooler is cylindrical
The LBZ replaced the LLY late in the 2006 model year and production continued through 2007. A large bump in output was seen with the introduction of the LBZ. Mechanically, the LBZ is very similar to the 2006 LLY model. The most significant difference between the LLY and LBZ is the computer controls. The LBZ features a much “wilder” tune, giving it a large increase in power horsepower and torque output.
| Years Produced | 2006 – 2007 |
| Displacement | 403 cubic inches, 6.6 liters |
| Configuration | 90 degree V8 |
| Compression Ratio | 16.8:1 |
| Bore | 4.06 inches |
| Stroke | 3.90 inches |
| Aspiration | • Variable geometry turbocharger (VGT) • air to air intercooler • 20 psi maximum boost pressure |
| Valvetrain | OHV, 4 valves per cylinder |
| Injection | • Direct injection, high pressure Bosch common rail injection system, CP3 injection pump • Maximum 26,000 psi injection pressure • Seven hole injectors |
| Horsepower | 360 hp @ 3,200 RPM |
| Torque | 650 lb-ft @ 1,600 RPM |
Quick Identifier:
LMMs were used from 2007.5-2010. Ways to identify this engine:
– Exposed injectors and injector harnesses
– Variable veined turbo charger
– No FICM (fuel injection control module) on the passenger side valve cover
– EGR cooler is rectangular
Nearly identical to the LBZ, the LMM debuted midway into the 2007 model year (2007.5). The slight variations between the LBZ and LMM gave the LMM a small boost in power output. The LMM features new emissions equipment that meet strict new diesel emission laws, and is currently in production today. Using a diesel particulate filter (DPF) and active regeneration technology, the LMM cut particulate matter emissions by 90 percent over the previous generation.
| Years Produced | 2007.5 – 2010 |
| Displacement | 403 cubic inches, 6.6 liters |
| Configuration | 90 degree V8 |
| Compression Ratio | 16.8:1 |
| Bore | 4.06 inches |
| Stroke | 3.90 inches |
| Aspiration | Intercooler & variable geometry turbocharger |
| Valvetrain | OHV, 4 valves per cylinder |
| Injection | 26,000 psi Bosch high pressure common rail w/ CP3 injection pump |
| Horsepower | 365 hp @ 3,100 RPM |
| Torque | 660 lb-ft @ 1,800 RPM |
Quick Identifier:
LMLs were used from 2011-2016. Ways to identify this engine:
– Orange wire loom on electrical harness due to high voltage
– Dual EGR coolers
The LML Duramax is released for 2011 model General Motors & Chevrolet HD trucks. The latest version of the 6.6L Duramax, the LML uses advanced emissions equipment, including the use of diesel exhaust fluid injection, to reduce nitrogen oxide emission levels by 63 percent over LMM powered trucks. This allows the LML to exceed currently mandated federal emissions requirements & meet future future requirements as well. Not only is the LML the cleaniest Duramax in history; it is also the most powerul, being released with 397 horsepower & 765 lb-ft of torque.
| Years Produced | 2011 – |
| Displacement | 403 Cubic Inches, 6.6 liters |
| Configuration | 90 degree V8 |
| Compression Ratio | 16.8:1 |
| Bore | 4.06 inches |
| Stroke | 3.90 inches |
| Aspiration | Variable geometry turbocharger w/air-to-air intercooler |
| Valvetrain | OHV, 4 valves per cylinder |
| Injection | • Direct injection • Bosch high pressure common rail • 30,000 psi max injection pressure |
| Horsepower | 397 hp @ 3,000 RPM |
| Torque | 765 lb-ft @ 1,600 RPM |
