General Motors Atlas engine

Atlas
Overview
Manufacturer	General Motors Corporation
Also called	Vortec
Production	2002–2012
Combustion chamber
Configuration	straight-4 straight-5 straight-6
Displacement	169-254 cu in (2770-4160 cc)
Cylinder block alloy	Aluminum
Cylinder head alloy	Aluminum
Valvetrain	DOHC
Compression ratio	10.0:1
Combustion
Fuel system	Multi-point fuel injection
Fuel type	Gasoline
Oil system	Wet sump
Cooling system	Water-cooled
Chronology
Predecessor	Chevrolet straight-6 engine General Motors 122 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 I4, I5, and I6 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.^[1]

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 2000 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 I6 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

LL8
Overview
Also called	Vortec 4200
Production	2002-2009
Combustion chamber
Configuration	straight-6
Displacement	4,160 cc (254 cu in)
Cylinder bore	93 mm (3.7 in)
Piston stroke	102 mm (4.0 in)
Output
Power output	270–291 hp (201–217 kW)
Torque output	275–277 lb·ft (373–376 N·m)

The LL8 (or Vortec 4200), is a straight-6 gasoline engine. 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 4,160 cc (254 cu in),^[2] with a 93 mm (3.7 in) bore and 102 mm (4.0 in) 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 (200 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.^[3]

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

L52

L52
Overview
Also called	Vortec 3500
Production	2004-2006
Combustion chamber
Configuration	straight-5
Displacement	3,460 cc (211 cu in)
Cylinder bore	93 mm (3.7 in)
Piston stroke	102 mm (4.0 in)
Output
Power output	220 hp (164 kW)
Torque output	225 lb·ft (305 N·m)

The L52 (also called Vortec 3500), is a straight-5 DOHC engine. It displaces 3,460 cc (211 cu in), with a 93 mm (3.7 in) bore and 102 mm (4.0 in) stroke. Dynoed at the flywheel it produces 220 hp (160 kW) at 5600 rpm and 225 lb·ft (305 N·m) at 2800 rpm, while producing 179.13 hp (133.58 kW) at 6001 rpm when dynoed at the rear wheels . Engine redline is 6300 rpm.^[4]

Applications:

• 2002 Bel Air concept
• 2004–2006 Chevrolet Colorado
• 2004–2006 GMC Canyon
• 2006 Isuzu i-350
• 2006 Hummer H3

LLR

The LLR (also called Vortec 3700), is a straight-5 DOHC engine. It displaces 3,653 cc (223 cu in), courtesy of a larger 95.5 mm (3.76 in) bore while keeping the 102 mm (4.0 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.^[5]

Applications:

• 2007–2012 Chevrolet Colorado
• 2007–2012 GMC Canyon
• 2007–2010 Hummer H3
• 2007–2008 Isuzu i-370

LK5

The LK5 (also called the Vortec 2800) is a 2,770 cc (169 cu in) straight-4 DOHC engine, with a 93 mm (3.7 in) bore and 102 mm (4.0 in) stroke. It produces 175 hp (130 kW) at 5600 rpm and 185 lb·ft (251 N·m) of torque at 2800 rpm.^[6] The engine redline is 6300 rpm.^[7]

Applications:

• 2004–2006 Chevrolet Colorado
• 2004–2006 GMC Canyon
• 2006-2008 Isuzu i-280

LLV

The LLV (also called Vortec 2900) is a 2,921 cc (178.3 cu in)^[8] straight-4 DOHC engine, with a 95.5 mm (3.76 in) bore and a 102 mm (4.0 in) 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.^[9]

Applications:

• 2007–2012 Chevrolet Colorado
• 2007–2012 GMC Canyon
• 2007–2009 Isuzu i-290

References

External links

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