Template:Infobox automobile engine Atlas is a name for a family of modern inline piston engines for trucks from General Motors, used in the GMT355 and GMT360 platforms. The series debuted in 2002 with the Oldsmobile Bravada, and is also used in the Buick Rainier, the Chevrolet TrailBlazer and Colorado, the GMC Envoy and Canyon, the Hummer H3, Isuzu Ascender and i-370, and the Saab 9-7X. The engines use GM's Vortec name, and straight-4, straight-5, and straight-6 engines are all part of the same family, sharing the same manufacturing equipment, rods, pistons, valves, and other parts. They feature coil-on-plug ignition systems,<ref name="counterman">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> variable valve timing on the exhaust side, electronic throttle control, and a special oil pan with a pass-through for the half shafts in four-wheel drive vehicles. The inclusion of VVT on the exhaust camshaft side allows the Atlas series to meet emissions standards without the use of EGR, simplifying the engine design and increasing power for a broad power curve. The LL8 shares 75% of its components with the LK5 and L52; while the LK5 and L52 share 89% of their components.<ref name="2005_GM">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
The Atlas engines feature aluminum cylinder blocks and heads, with the cylinder bores featuring replaceable steel cylinder liners.<ref name="counterman"/> The 4- and 5-cylinder versions feature dual balance shafts,<ref name="2006_LK5" /><ref name="2006_L52" /> balance shafts being unnecessary in the 6-cylinder.<ref>Template:Citation</ref>
The Atlas program began in 1995 along with the planning for GM's next-generation mid-size SUVs and pickup trucks. These vehicles were designed around the I6 engine. The I6 version was used in a Baja 1000 racing truck, winning its first race in a class that also included V8 engines. Another I6-powered truck won the truck class at the Pikes Peak International Hillclimb.
The Atlas engines were produced at the Flint Engine South plant in Flint, Michigan, while the I4 and I5 versions were produced at the Tonawanda Engine plant in Tonawanda, New York, near Buffalo.
LL8 (Vortec 4200)Edit
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The LL8 (or Vortec 4200), is a straight-6 gasoline engine produced from 2002 to 2009. It was the first Atlas engine, and was introduced in 2002 for the Chevrolet TrailBlazer, GMC Envoy, and Oldsmobile Bravada. The engine was also used in the Buick Rainier, Saab 9-7X, and Isuzu Ascender.
It displaces Template:Cvt, with a Template:Cvt bore and stroke. It has four valves per cylinder, utilizes dual-overhead cams (DOHC) design, and features variable valve timing on the exhaust cam, a first for GM inline engines. When introduced, this engine's power was Template:Cvt at 6,000 rpm and torque was Template:Cvt at 3,600 rpm. 2003 saw a slight bump in power to Template:Cvt, while torque was unchanged. For 2006, power was increased to Template:Cvt at 6,000 rpm and torque to Template:Cvt) at 4800 rpm with the addition of a MAF and a complete internal redesign of the engine; however, due to the new SAE rating procedures, ratings can vary slightly between years. The engine redline is 6,300 rpm. The LL8 was on the Ward's 10 Best Engines list for 2002 through 2005 and was the basis for all the other Atlas engines. With the closure of the Moraine, Ohio, plant and the discontinuation of the GMT360 platform (Chevrolet TrailBlazer, GMC Envoy, etc.), production of the LL8 also ended.<ref name="2007_LL8">Template:XLSlink</ref>
Applications:
- 2002–2009 GMC Envoy, Envoy XL, and Envoy XUV
- 2002–2009 Chevrolet TrailBlazer and TrailBlazer EXT
- 2002–2004 Oldsmobile Bravada
- 2004–2007 Buick Rainier
- 2003–2008 Isuzu Ascender
- 2005–2009 Saab 9-7X 4.2i
LLR (Vortec 3700)Edit
The LLR (also called Vortec 3700), is a straight-5 DOHC engine produced from 2007 through 2012. It displaces Template:Cvt, courtesy of a larger Template:Cvt bore while keeping the Template:Cvt stroke. The LLR also corrected the head issue found in the L52. It produces Template:Cvt at 5,600 rpm and Template:Cvt at 4,600 rpm. The engine redline is 6,300 rpm.<ref name="2007_LL8"/>
Applications:
- 2007–2012 Chevrolet Colorado and GMC Canyon
- 2007–2010 Hummer H3
- 2007–2008 Isuzu i-370
L52 (Vortec 3500)Edit
The L52 (also called Vortec 3500), is a straight-5 DOHC engine produced from 2004 through 2006. It displaces Template:Cvt, with a Template:Cvt bore and stroke. Dynoed at the flywheel it produces Template:Cvt at 5,600 rpm and Template:Cvt at 2,800 rpm. The engine redline is 6,300 rpm.<ref name="2006_L52">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Applications:
- 2002 Bel Air concept
- 2004–2006 Chevrolet Colorado and GMC Canyon
- 2006 Isuzu i-350
- 2006 Hummer H3
LLV (Vortec 2900)Edit
The LLV (also called Vortec 2900) is a Template:Cvt straight-4 DOHC engine produced between 2007 and 2012, with a Template:Cvt bore and a stroke. It replaced the LK5 and produced Template:Cvt at 5,600 rpm and Template:Cvt of torque at 2,800 rpm. The engine redline is 6,300 rpm.<ref name="2007_LLV">Template:XLSlink</ref>
Applications:
- 2007–2012 Chevrolet Colorado and GMC Canyon
- 2007–2008 Isuzu i-290
LK5 (Vortec 2800)Edit
The LK5 (also called the Vortec 2800) is a Template:Cvt straight-4 DOHC engine produced between 2004 and 2006, with a Template:Cvt bore and stroke. It produces Template:Cvt at 5,600 rpm and Template:Cvt of torque at 2,800 rpm. The engine redline is 6,300 rpm.<ref name="2006_LK5">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Applications:
- 2004–2006 Chevrolet Colorado and GMC Canyon
- 2006 Isuzu i-280