6.6 L Duramax LLY

6.6L Duramax engineThe 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 furture. 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 2006, but the engines were mechanically identical. LLY's were used in the Hummer H1, Chevrolet Silverado HD, and GMC Sierra HD.

 

6.6 L LLY Specifications:

 

Configuration:
V8
Displacement:
403 cubic inches, 6.6 liters
Compression Ratio:
17.5:1 (16.8:1 in 2006)
Bore:
4.06 inches
Stroke:
3.90 inches
Aspiration:
Turbocharged w/ intercooler
Valvetrain:
OHV, 4 valves per cylinder
Oil Capacity:
10 quarts w/filter
Weight:
approx. 835 lbs
*Horsepower:

310 hp @ 3,000 RPM
320 hp @ 3,000 RPM in 2006

*Torque:
520 lb-ft @ 1,600 RPM
560 lb-ft @ 1,600 RPM in 2006

*output varies slightly with model year.

 

 

2006 LLY Changes:

On a mechanical level, the 2006 LLY was nearly identical to the previous version, however the following changes were made to the 2006 version:

  • Main bearing upgraded for longevity.
  • Compression lowered to 16.8:1.
  • Thicker connecting rods.
  • Revised cylinder heads to match lowered compression ratio.
  • Fuel injection pressure raised to 26,000 psi from 23,000 psi.
  • New fuel injector design.
  • New variable geometry turbocharger for cleaner emissions & better throttle response.
  • Larger EGR cooler installed.

6.6 L LLY Information:

  • LLY applications include the Chevrolet Silverado HD, Hummer H1, GMC Sierra HD, Chevrolet Kodiak, GMC Topkick.
  • First Duramax to feature emissions controls.

LLY 6.6L Duramax diesel engine