The Duramax is a General Motors diesel engine family for light-and medium duty trucks, designed
by Isuzu. The 6.6-liter Duramax is produced by DMAX, a joint venture between GM and Isuzu
in Moraine, Ohio. The Duramax block and heads are poured at The Defiance GM Powertrain foundry
in Defiance, Ohio. This engine was initially installed in 2001 model year Chevy and GMC
trucks and has been an option since then 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 V-8 diesel at its
Moraine facility.
Engine RPO Codes LB7
RPO LB7 was first introduced in 2001 and continued until mid-2004. It is a 32-valve design with
high-pressure common-rail direct injection and an experimental composite design cylinder
head. The most common issue with the LB7 is injector failure, so common that a special
policy bulletin was issued. Fuel leaked and entered the crankcase, causing oil dilution.
Early on, customers came forward complaining of severe overheating, and in some situations,
blown head gaskets. Initially GM denied it was a problem, but after being sued by a consumer
group, GM relented and included overheating and blown head gaskets as a warranted item.
GM issued a warranty for this after the fact for injectors, which now have 7 year/200,000
mile coverage. The following trucks use the LB7:
Chevrolet Kodiak/GMC Topkick Chevrolet Silverado/GMC Sierra HD
Specifications Engine type: 6,599 cc V8 turbo
Bore x Stroke: 4.06 in x 3.90 in Block / Head: Cast gray iron / Cast aluminum
Aspiration: Turbocharged & Intercooled Valvetrain: OHV 4-V
Compression: 17.5:1 Injection: Direct; Robert Bosch GmbH high
pressure common-rail Power / Torque: 300 bhp @ 3100 rpm / 520 lb·ft
@1800 rpm Source:
LLY The LLY is a 6,599 cc turbocharged engine
which debuted in mid-2004 and continued until the end of 2005. 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 they
installed an Exhaust Gas Recirculation valve or. 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 Hummer H1 Alpha Chevrolet Silverado/GMC Sierra HD
Specifications Engine type: 6,599 cc V8 turbo
Bore x Stroke: 4.06 in x 3.90 in Block / Head: Cast gray iron / Cast aluminum
Aspiration: Turbocharged & Intercooled Valvetrain: OHV 4-v
Compression: 17.5:1 Injection: Bosch High Pressure Common-rail
Power / Torque: 305 bhp @3000 rpm / 605 lb·ft @1600 rpm
Head casting is 8gf1 Block casting is #22351021213
Source: LLY/LBZ
The LBZ debuted in late 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 2005.5 LLY version of the motor. First appearance of the Duramax in the Express/Savanna
vans. 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 helps lower compression ratio to 16.8:1 from 17.5:1
Piston pin bore diameter increased for increased strength
Connecting rod “ I ” section is thicker for increased strength
Cylinder heads revised to accommodate lower compression and reduced cylinder firing pressure
Maximum injection pressure increased from 23,000 psi to more than 26,000 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: Chevrolet Silverado HD
Chevrolet Kodiak GMC Sierra HD
GMC TopKick LLY applications:
Chevrolet Silverado HD Chevrolet Kodiak
GMC Sierra HD Chevrolet Express full-size
GMC Savana full-size Specifications
Engine type: 6,599 cc V8 turbo Bore x Stroke: 4.06 in x 3.90 in
Block / Head: Cast gray iron / Cast aluminum Aspiration: Turbocharged & Intercooled
Valvetrain: OHV 4-V Compression: 16.8:1
Injection: Bosch High Pressure Common-rail Power / Torque:
Source: LMM
The LMM 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 2008-2010. A version was used in Trident Iceni.
Specifications Engine type: 6,599 cc V8 turbo
Bore x Stroke: 4.06 in x 3.90 in Block / Head: Cast gray iron / Cast aluminum
Aspiration: Turbocharged & Intercooled Valvetrain: OHV 4-V
Compression: 16.8:1 Injection: Bosch High Pressure Common Rail
with CP3.3 Injection Pump Power / Torque: 365 bhp @3200 rpm / 660 lb·ft
@1600 rpm Source:
Emission controls: Additional combustion control, including an
even more efficient variable-geometry turbocharging system, cooled exhaust gas recirculation and
closed crankcase ventilation to reduce nitrogen oxides
Additional exhaust control, including oxidizing catalyst and new diesel particulate filter
to reduce soot and particulate matter Increased-capacity cooling system
New engine control software Use of low-ash engine oil
Applications: 2007- Chevrolet Silverado HD
2007- GMC Sierra HD Chevrolet Kodiak
GMC Topkick Chevrolet Express/GMC Savanna
LMK This engine is not yet commercially launched
although it was touted in the automobile press as one of the most important new engine concepts
for small trucks and SUVs by finally delivering a capable diesel engine in a compact enough
package. The engine project is current on indefinite hold by GM. General Motors planned
a 4.5-litre 72-degree V8 for light-duty applications which would be built at GM's powertrain facility
in Tonawanda, New York after 2009. Designed to fit in the same space as a Chevrolet Small-Block
engine, it is expected to produce over 310 bhp and 520 lb·ft of torque. It added urea injection,
29,000-psi piezo-electric common-rail fuel system over previous Duramax architecture.
It was initially targeted for the Chevy Silverado/GMC Sierra and Hummer H2. Unlike previous Duramax
engines, the 4.5-liter is planned to be designed and built entirely by GM, without assistance
from Isuzu. As of March 2009, a GM spokesperson stated
the engine project has been put on an "indefinite hold" due to current economic conditions.
LML The 6.6L RPO LML is the latest version of
the Isuzu/GM Duramax V8 diesel engine and actually 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 provide improved exhaust emissions that comply with the new federal emission
standards for diesel engines, provide better engine rigidity and further noise reduction.
New 29,000 PSI piezo injectors, a complete fuel system-hardening to tolerate up to 20%
biodiesel mixtures and urea injection with a 5.3 gallon urea tank are updating the fuel
and emissions systems. 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 horsepower at 3000 rpm and 765 lb·ft of torque at 1600 rpm.
LGH The 6.6L Duramax diesel engine is used on
2010 interim and 2011 Chevrolet Express and GMC Savana vans and 2011 Chevrolet Silverado
and GMC Sierra trucks with RPO ZW9. The LGH engine is rated at 335 bhp at 3100 rpm and
685 lb·ft at 1600 rpm. Similar to the LML this engine also uses a DPF and DEF system
to meet emission standards. See also
List of GM engines Allison 1000 transmission
References
External links GM Powertrain
Duramax home page DMAX, Ltd. home page
Duramax Diesel Specs