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

LB7 Duramax Engine Bare Long Block

Remanufactured 6.6-Liter LB7 Duramax Engine – Bare Long Block – Built to Factory New Specifications with Updates – Diesel Experts

SKU: LB7 Bare Long Block Categories: , ,

Product Description

6.6-Liter LB7 Duramax Engine

The Duramax Engine is a General Motors diesel engine family for light to medium duty trucks. The 6.6-liter LB7 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 LB7 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 LB7 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 LB7 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 LB7 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

2001, 2002, 2003, 2004


Chevrolet, Duramax, GMC


Kodiak C4500, Kodiak C5500, LB7, LBZ, LLY, LML, LMM, 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 LB7, 90 degree V-8 dieselYears

Produced:2001 – 2004 model years

VIN Code:1 (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

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

Bore:4.06 inches

Stroke:3.90 inches

Aspiration:Turbocharged & intercooled – IHI turbocharger, air-to-air intercooler

Injection:Direct injection, Bosch 23,000 psi high pressure common rail with CP3 injection pump

Valvetrain:OHV (overhead valve), 4 valves per cylinder (32 valve)

Oil Capacity:10 quarts w/ filterEngine

Weight:Approx. 835 lbs

Max Engine Speed:3,250 rpm

Peak Horsepower:• 235 hp @ 2,700 rpm (2001 model year)• 300 hp @ 3,100 rpm (2004 model year)

Peak Torque:• 500 lb-ft @ 1,600 rpm (2001 model year)• 520 lb-ft @ 1,800 rpm (2004 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.