Duramax V8 engine

The Duramax V8 engine is a family of 6.6-liter diesel V8 engines produced by DMAX, a wholly owned subsidiary of General Motors in Moraine, Ohio. The Duramax block and heads are supplied from reliable vendors of General Motors. This engine was initially installed in 2001 Chevrolet and GMC trucks, and has since become an option in pickups, vans, and medium-duty trucks. In 2006, production at Moraine was reportedly limited to approximately 200,000 engines per year. On May 9, 2007, DMAX announced the production of the 1,000,000th Duramax V8 at its Moraine facility, followed by the 2,000,000th on March 24, 2017.

LB7
RPO LB7 (engine code "1") was first introduced in 2001 and continued until early 2004. It is a 32-valve design with high-pressure common-rail direct injection and an experimental composite design cylinder head.

The following trucks use the LB7:
 * Chevrolet Kodiak/GMC TopKick
 * Chevrolet Silverado/GMC Sierra HD

Specifications
The LLY was introduced in 2004 and completely replaced the LB7 by mid-year.
 * Block / Head: Cast Iron / Aluminum
 * Compression: 17.5:1
 * Injection: Direct; Bosch high-pressure common-rail
 * Power / Torque: 300 hp at 3,100 rpm / 520 lb.ft at 1,800 rpm

LLY
The LLY (internally called the 8GF1) (engine code "2") is a 6619 cc turbocharged engine which debuted in mid-2004 and continued until the end of 2005 (except the Hummer H1 in 2006). It is a 32-valve design with high-pressure common-rail direct injection and aluminum cylinder heads. The LLY was GM's first attempt to implement emissions requirements on their diesel trucks. To meet this goal, they turned to a newly developed Garrett turbocharger with a variable geometry vane system and installed an EGR valve. Learning from problems with injectors in the previous LB7, GM changed the valve covers to allow access to the injectors without having to remove the valve covers, saving significant labor costs if injector replacement became necessary.

The following trucks used the LLY engine:
 * 2006-only Hummer H1 Alpha
 * Chevrolet Silverado/GMC Sierra 2500HD/3500

Specifications

 * Block / Head: Cast gray iron / Cast aluminum
 * Compression: 17.5:1
 * Injection: Bosch high-pressure common-rail
 * Power / Torque: 310 bhp at 3000 rpm / 605 lbft at 1600 rpm
 * Head casting is 8GF1
 * Block casting is #22351021213

LLY/LBZ
There are two VIN codes for the LBZ. The first is VIN 2 produced in late 2005 and early 2006. The VIN 2 engine is mechanically and physically the same as the VIN D engine but utilizes LLY engine tuning due to the LBZ tuning taking longer to be EPA certified and placed into production.

The second is VIN D. This was introduced in 2006 and continued into 2007 sold only in the "classic" body style. It has an improved engine computer tune that produces increased power and torque over the 2005 LLY version of the engine. This also marked the first appearance of the Duramax in the Express/Savana vans. The LBZ is one of the more sought-after Duramax engines because of its strength, reliability, and being pre-emissions (DPF appeared on the next generation LMM in 2007).

Changes include:
 * Cylinder block casting and machining changes strengthen the bottom of the cylinder bores to support increased power and torque
 * Upgraded main bearing material increases durability
 * Revised piston design lowers compression ratio to 16.8:1 from 17.5:1
 * Piston pin bore diameter increased for added strength
 * Connecting rod "I" section is thicker for added strength
 * Cylinder heads revised to accommodate lower compression and reduced cylinder firing pressure
 * Maximum injection pressure increased from 23000 psi to more than 26000 psi
 * Fuel delivered via higher-pressure pump, fuel rails, distribution lines and all-new, seven-hole fuel injectors
 * Fuel injectors spray directly onto glow plugs, providing faster, better-quality starts and more complete cold-start combustion for reduced emissions
 * Improved glow plugs heat up faster through an independent controller
 * Revised variable-geometry turbocharger is aerodynamically more efficient to help deliver smooth and immediate response and lower emissions
 * Air induction system re-tuned to enhance quietness
 * EGR has larger cooler to bring more exhaust into the system
 * First application of new, 32-bit E35 controller, which adjusts and compensates for the fuel flow to bolster efficiency and reduce emissions

LBZ applications:

LLY applications:
 * Chevrolet Silverado 2500HD/3500
 * Chevrolet Kodiak
 * GMC Sierra 2500HD/3500
 * GMC TopKick
 * Chevrolet Silverado/GMC Sierra 2500HD/3500 Classic
 * Chevrolet Silverado 2500HD/3500
 * Chevrolet Kodiak
 * GMC Sierra 2500HD/3500
 * Chevrolet Express full-size (reduced power output mated to a 4L85E transmission)
 * GMC Savana full-size (reduced power output mated to a 4L85E transmission)

Specifications

 * Block / Head: Cast gray iron / Cast aluminum
 * Compression: 16.8:1
 * Injection: Bosch high-pressure common-rail
 * Power / Torque: 360 bhp @3200 rpm / 650 lb-ft @1600 rpm

LMM
The LMM (engine code "6") debuted part way through 2007 and ended production with the start of the 2011 calendar year and is mated to the 6-speed Allison transmission. The LMM was the only Duramax offered for model years 2007–2010. A version was used in the Trident Iceni.

Specifications

 * Block / Head: Cast gray iron / Cast aluminum
 * Compression: 16.8:1
 * Injection: Bosch high-pressure common-rail with CP3.3 injection pump
 * Power / Torque: 365 bhp at 3200 rpm / 660 lbft at 1600 rpm

Emission controls:
 * Additional combustion control, including an even more efficient variable-geometry turbocharging system, cooled (enhanced) exhaust gas recirculation (EGR), and closed crankcase ventilation to reduce nitrogen oxides (NOx)
 * Additional exhaust control, including oxidizing catalyst and new diesel particulate filter (DPF) to reduce soot and particulate matter
 * Increased-capacity cooling system
 * New engine control software
 * Use of low-ash engine oil (CJ-4)

Applications:
 * 2007–2010 Chevrolet Silverado HD
 * 2007–2010 GMC Sierra HD
 * 2007–2010 Chevrolet Kodiak
 * 2007–2010 GMC TopKick
 * 2007–2010 Chevrolet Express/GMC Savana

LGH
The 6.6L Duramax diesel engine (VIN code "L") is used on 2010 interim and 2011 Chevrolet Express and GMC Savana vans and 2011 Chevrolet Silverado/GMC Sierra HD trucks with RPO ZW9 (chassis cabs or trucks with pickup box delete). The LGH engine is rated at 335 bhp at 3,100 rpm and 685 lbft at 1,600 rpm. Similar to the LML, this engine also uses a DPF and DEF system to meet emissions standards.

LML
The 6.6L RPO LML (VIN code "8") is the 2011–2016 version of the Isuzu/GM Duramax V8 diesel engine. It is a further advanced version of the LMM engine with the majority of the changes addressing a required drastic reduction in engine emissions. Some mechanical aspects of the engine, such as piston oil flow design for improved temperature control and oil pump design, were also improved to enhance durability even further.

The LML engine was significantly updated for 2011 to comply with the new federal emissions standards for diesel engines, provide better engine rigidity, and further noise reduction. The engine gained new 29,000 PSI piezo injectors as well as a completely reworked fuel system which was now powered by the Bosch CP4 pump, that also now supports up to 20% biodiesel mixtures and a urea injection (to reduce nitrogen oxides) with a 5.3 gallon DEF tank. This engine has a fuel injector in the exhaust tract, to allow raw fuel injection during the particulate filter recycling routine. The RPO LML engine is rated at 397 hp at 3,000 rpm and 765 lbft of torque at 1,600 rpm.

L5P
The L5P Duramax is the latest version of the Duramax V8 diesel engine.(engine code Y). Introduced in the 2017 model year, it was the most powerful diesel engine GM had produced, with 445 hp at 2,800 rpm and 910 lbft at 1,600 rpm. Design specification performance can exceed 550 bhp at 3,050 rpm and 1050 lbft at 1,975 rpm.

L5P Gen2
The L5P Duramax received an increase in horsepower and torque for the 2024 model year; 470 hp at 2,800 rpm and 975 lbft at 1,600 rpm. Design specification performance can exceed 550 bhp at 3050 rpm and 1050 lbft at 1975 rpm.

L5D
The L5D Duramax is a downrated version of the L5P for the Chevrolet Silverado MD and International CV trucks (Class 4, 5, and 6). The L5D was downrated to increase reliability and reduce downtime. The L5D was introduced in 2018 for the 2019 Chevrolet Silverado MD and International CV trucks. Specifications for the L5D are 350 hp at 2,600 rpm and 700 lbft at 1,600 rpm.