General Motors Atlas engine
Atlas is a name for a family of modern inline piston engines for trucks from General Motors, used in the GMT 355 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 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.
|Manufacturer||General Motors Corporation|
|Configuration||Straight-4, 5 or 6 cylinders|
|Piston stroke||102 mm (4.02 in)|
|Valvetrain||DOHC 4 valves x cyl. with VVT|
|Fuel system||Multi-point fuel injection|
|Oil system||Wet sump|
|Power output||175–291 hp (130–217 kW)|
|Torque output||185–277 lb⋅ft (251–376 N⋅m)|
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 LL8 (or Vortec 4200), is a straight-6 gasoline engine produced between 2002 and 2009. It was the first Atlas engine, and was introduced in 2002 for the Chevrolet TrailBlazer, GMC Envoy, and Oldsmobile Bravada, the engine is also in use in the Buick Rainier, Saab 9-7, and the Isuzu Ascender. It displaces 4.2 L; 253.9 cu in (4,160 cc), with a 93 mm × 102 mm (3.66 in × 4.02 in) 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 270 hp (201 kW) at 6000 rpm and torque was 275 lb⋅ft (373 N⋅m) at 3600 rpm. 2003 saw a slight bump in power to 275 hp (205 kW), while torque was unchanged. For 2006, power was increased to 291 hp (217 kW) at 6000 rpm and torque to 277 lb⋅ft (376 N⋅m)) 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. Engine redline is 6300 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 closing of the Moraine, Ohio plant and the termination of the GMT360 platform (Chevrolet TrailBlazer, GMC Envoy, etc.) the production of the LL8 was also terminated.
The L52 (also called Vortec 3500), is a straight-5 DOHC engine produced between 2004 and 2006. It displaces 3.5 L; 211.1 cu in (3,460 cc), with a 93 mm × 102 mm (3.66 in × 4.02 in) bore and stroke. Dynoed at the flywheel it produces 220 hp (164 kW) at 5600 rpm and 225 lb⋅ft (305 N⋅m) at 2800 rpm. Engine redline is 6300 rpm.
The LLR (also called Vortec 3700), is a straight-5 DOHC engine produced between 2007 and 2012. It displaces 3.7 L; 222.9 cu in (3,653 cc), courtesy of a larger 95.5 mm (3.76 in) bore while keeping the 102 mm (4.02 in) stroke. The LLR also corrected the head issue found in the L52. It produces 242 hp (180 kW) at 5600 rpm and 242 lb⋅ft (328 N⋅m) at 4600 rpm. Engine redline is 6300 rpm.
The LK5 (also called the Vortec 2800) is a 2.8 L; 169.0 cu in (2,770 cc) straight-4 DOHC engine produced between 2004 and 2008, with a 93 mm × 102 mm (3.66 in × 4.02 in) bore and stroke. It produces 175 hp (130 kW) at 5600 rpm and 185 lb⋅ft (251 N⋅m) of torque at 2800 rpm. The engine redline is 6300 rpm.
The LLV (also called Vortec 2900) is a 2.9 L; 178.3 cu in (2,921 cc) straight-4 DOHC engine produced between 2007 and 2012, with a 95.5 mm × 102 mm (3.76 in × 4.02 in) bore and a stroke. It replaced the LK5 and produced 185 hp (138 kW) at 5600 rpm and 190 lb⋅ft (258 N⋅m) of torque at 2800 rpm. Engine redline is 6300 rpm.
- http://archives.media.gm.com/division/2005_prodinfo/powertrain/index.html. Retrieved 16 April 2014. Missing or empty
- http://media.gm.com/us/powertrain/en/product_services/2007/Spec%20Sheet/Line%20456/2007_LL8.xls. Retrieved October 27, 2008. Missing or empty
- 2007 LL8 Spec Sheet
- "2006 Vortec 3500 3.5L I-5 (L52) Spec Sheet" (PDF).
- 2007 LLR Spec Sheet
- (PDF) http://media.gm.com/us/powertrain/en/product_services/2006/Spec%20Sheets/Line%20456/2006%20Line%20I4%20Truck%20(LK5).pdf. Retrieved October 27, 2008. Missing or empty
- "2006 Vortec 2.8L I-4 (LK5) Spec Sheet" (PDF).
- http://media.gm.com/us/powertrain/en/product_services/2007/Spec%20Sheet/Line%20456/2007_LLV.xls. Retrieved October 27, 2008. Missing or empty
- 2007 LLV Spec Sheet
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