LB7 Duramax Engine LLY Duramax Engine LBZ Duramax Engine LMM Duramax Engine LML Duramax Engine

LLY Duramax Engine Bare Long Block

SKU: LLY Bare Long Block Categories: , ,

Product Description

6.6-Liter LLY Duramax Engine

The Duramax Engine is a General Motors diesel engine family for light to medium duty trucks. The 6.6-liter LLY Duramax Engine is produced by DMAX, a joint venture between GM and Isuzu in Moraine, Ohio. The Duramax Engine was released in late 2001 into the Chevrolet and GMC chassis vehicles. The LLY Duramax Engine was replacing the old 6.5-L Detroit built engine which was a big jump forward in technology. GM was the first of the manufacturers to make this jump and gave GM an added advantage in the diesel truck market. The LLY Duramax Engine utilized the new Bosch Common Rail Fuel system. The early fuel systems included an ECM (Engine Control Module), CP3 Injection pump, FICM (Fuel Injection Control Module), and injectors. The later version fuel system did away with the FICM and utilize a CP4 injection pump. The common rail term comes from the fuel rail that is shared by all injectors.

The LLY Duramax Engine had some issues that appeared not too long after initial release. GM extended the warranty on the injectors to 200,000 miles due to failures that were widespread. Changing the injectors on the early Duramax was a little time consuming since they were located under the valve cover. Air bubbles in the fuel lines turned out to be the cause for the premature failure of the injectors. When these air bubbles were present in the fuel line they accumulated in the CP3 pump. When the injector went to fire the bubble would get between the injector plunger and the injector tip. With the bubble there the injector plunger has no fluid damping when it comes into contact with the injector tip causing a small gap to form over time. Once that gap grows large enough fuel is allowed to flow through continuously since the  rail is pressurized so high. The computer system was unable to determine if this is happening so the check engine light would not notified the driver. The only way to determine if this was happening was to measure the return fuel flow rate.

Aftermarket companies like AirDog & FASS came up with the solution to the injector failures called a Fuel Air Separation System. Once one of these systems was added to the vehicles they proved to extend the life of the injectors to around 400,000 miles according to many “hot shot” drivers & fleet vehicle owners.

Additional Information

Weight 835 lbs
Dimensions 48 x 48 x 40 in

2004, 2005, 2006


Chevrolet, Duramax, GMC


Kodiak C4500, Kodiak C5500, LLY, Sierra 2500HD, Sierra 3500HD, Silverado 2500HD, Silverado 3500HD, Topkick C4500, Topkick C5500

Engine Size


Whats Included

Cylinder Block

Cylinder Heads & Valetrain


Camshaft Pistons/rings

Timing gears

Connecting rods


Main/rod bearings

Cam bearings

Valve train

Oil pump

Gasket Set


  • Assembled in the USA.
  • All the internal wearable parts such as bearings, gaskets, pistons are replaced with New.
  • Cylinder Blocks and Cylinder Heads are magna-flux tested to avoid micro fractures.
  • Cylinders are bored back to Original Equipment Specs, or sleeved.
  • 100% Standard sized crankshafts are used in these engines, no reground and re nitrated.
  • Cylinder heads get new valves and are vacuum tested to ensure the quality of the valve job. All heads are then pressure tested.
  • Connecting rods have new bushings installed and both large and small end are re machined to OEM specifications and gram weight.
  • New high pressure GM oil pumps are used for durability
  • Core plugs are 100% stainless steel to avoid corrosion.
  • 100% internal wear components including rings, bearings, bushings, gaskets and seals.

Technical Specs

Engine:6.6L Duramax LLY, 90 degree V8 diesel

Years Produced:2004 – 2006

VIN Code:2 (8th digit of VIN)

Displacement:403 cubic inches, 6.6 liters

Head/Block Material:Aluminum cylinder heads, cast iron engine block

Compression Ratio:17.5 : 1 (2004 & 2005 model years), 16.8 : 1 (2006 model year)

Firing Order:1-2-7-8-4-5-6-3

Bore:4.06 inchesStroke:3.90 inches

Aspiration:Turbocharged and intercooled; Garrett variable vane turbocharger (VVT), air-to-air intercooler

Injection:Direct injection, 23,000 (26,000 for 2006 MY) psi Bosch high pressure common rail with CP3 injection pump

Valvetrain:OHV (overhead valve), 4 valves per cylinder

Oil Capacity:10 quarts w/ filterEngine

Weight:Approx. 835 lbs

Max Engine Speed:3,250 rpm

Emissions Equipment:Exhaust gas recirculation (EGR) and diesel oxidation catalyst (DOC)

Peak Horsepower:310 hp @ 3,000 rpm

Peak Torque:• 520 lb-ft @ 1,600 rpm (2004 & 2005 model years)• 605 lb-ft @ 1,600 rpm (2006 model year)


The 6.6-L Duramax Bare Long Block Engines come with a 18 Month Unlimited Mileage Parts Replacement Warranty.
Labor is covered at book rate times for manufacturing defects.


Shipping is handled via common freight carrier. Freight is calculated by zip code and weight of the engine round trip unless specified differently.