The 6.6-liter LB7 Duramax turbo-diesel engine was the result of a joint effort between General Motors and Isuzu, and was utilized by the first-generation Chevrolet Silverado HD and GMC Sierra HD.
| Displacement: | 6.6L / 403 cu. in. |
|---|---|
| Aspiration: | Natural |
| Vehicles: | Chevrolet Silverado HD, GMC Sierra HD |
| Introduced: | 2001 model year |
| Discontinued: | 2004 model year |
| Predecessor: | – |
| Successor: | LLY Duramax V8 |
| Assembly: | Moraine, Ohio, USA |
The LB7 was first produced back in 2001 through 2004 for use in Chevrolet Silverado HD and GMC Sierra HD models, where it made up to 300 horsepower and 520 pound-feet of torque, and was mated to a commercial-grade 5-speed automatic Allison transmission.
While the LB7 is renowned for its overall reliability and simplicity versus newer diesel powerhouses. The LB7 was featured first-in-class common rail direct fuel injection, and an infamous characteristic of the LB7 is an injector failure issue. The failure rate was high enough to trigger a recall, wherein GM replaced the original injectors and extended the warranty to 200,000 for the new components. Reports indicate that poorly filtered fuel was one of the leading causes of failure, though aftermarket manufacturers have since stepped in to relieve this problem. Aside from this fueling issue, the LB7 is regarded as a very stout power plant.
Regarding its simplicity, the LB7 was built before stringent diesel emissions regulations, meaning there’s no fuss over Diesel Exhaust Fluid (DEF), Diesel Particulate Filter (DPF), or Selective Catalytic Reduction (SCR) woes.
The LB7 Duramax V8 would eventually evolve into the current-day
L5P Duramax V8, which produces 445 horsepower and a lofty 9100 pound-feet of torque under the hoods of the all-new 2020 Chevrolet Silverado HD and 2020 GMC Sierra HD pickups. A derivative of the L5P, the L5D Duramax V8, is used in the 2019 Chevrolet Medium Duty Trucks – including the 2019 Silverado 4500HD, Silverado 5500HD and Silverado 6500HD.
| Type | 6.6L V-8 Turbo-Diesel |
| GM RPO Code | LB7 |
| Displacement | 403 ci |
| Compression Ratio | 17.5:1 |
| Valve Configuration | Overhead |
| Valves Per Cylinder | 4 |
| Assembly Site | Moraine, Ohio, USA |
| Valve Lifters | Mechanical roller |
| Firing Order | 1 – 2 – 7 – 8 – 4 – 5 – 6 – 3 |
| Bore x Stroke | 4.055 in. or 103 mm x 3.897 in. or 99 mm |
| Fuel System | Direct injection with high-pressure common rail w/ Bosch CP3 pump |
| Fuel Type | Diesel |
| Fuel Tank Size: | 26 Gallons |
| Maximum Powered Speed | 3250 rpm |
| Emissions Controls | None |
| Block | Cast iron |
| Cylinder Head | Cast aluminum |
| Intake Manifold | Cast aluminum |
| Exhaust Manifold | Cast nodular iron with steel pipe extension |
| Main Bearing Caps | Cast nodular iron |
| Crankshaft | Forged steel |
| Camshaft | Steel |
| Connecting Rods | Forged Steel |
| Engine Oil Capacity | 10 qt./9.5L w/ Filter |
| Engine Mass: | Approximately 835 pounds |
| Year | Make | Model | Transmission | Power (hp / kW) @ RPM | Torque (lb-ft / Nm) @ RPM |
|---|---|---|---|---|---|
| 2001-2003 | Chevrolet | Silverado HD | 5-Speed Manual or 5-Speed Allison Automatic | 235 / 175 @ 2700 | 500 / 678 @ 1600 |
| 2001-2003 | GMC | Sierra HD | 5-Speed Manual or 5-Speed Allison Automatic | 235 / 175 @ 2700 | 500 / 678 @ 1600 |
| 2004 | Chevrolet | Silverado HD | 5-Speed Manual or 5-Speed Allison Automatic | 300 / 225 @ 3100 | 520 / 705 @ 1800 |
| 2004 | GMC | Sierra HD | 5-Speed Manual or 5-Speed Allison Automatic | 300 / 225 @ 3100 | 520 / 705 @ 1800 |
The 6.6L Duramax LB7 engine was manufactured at the GM Duramax plant in Moraine, Ohio, USA.
Follow our Duramax LB7 news coverage.
