| Manufacturer | General Motors Corporation |
|---|---|
| Production | 2002–present |
| Predecessor | Chevrolet Straight-6 engine |
| Displacement | 169-254 cu in (2770-4160 cc) |
Atlas is a name for a family of modern inline piston engines for trucks from General Motors. The series debuted in 2002 with the Oldsmobile Bravada, and is also used in the Chevrolet TrailBlazer and Colorado and their GMC twins, the Envoy and Canyon. In production, 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 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 are currently produced at the Tonawanda Engine plant in Tonawanda, New York.
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The LL8 (or Vortec 4200), is a straight-6 truck engine. It was the first Atlas engine, and was designed for GM's new SUV line. It displaces 4.2 L (4160 cc, 254 cu in),[1] with a 93 mm (3.7 in) bore and 102 mm (4.0 in) stroke. When introduced, this engine's power was 270 hp (205 kW) at 6000 rpm and torque was 275 ft·lbf (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 ft·lbf (376 N·m) at 4800 rpm with the addition of a MAF and a complete internal redesign of the engine. The Atlas LL8 was on the Ward's 10 Best Engines list for 2002 through 2005. Engine redline is 6300 rpm.
LL8 Applications:
With the closing of the Moraine, OH plant and the termination of the GMT-360 platform (Chevrolet TrailBlazer, GMC Envoy, etc) the Atlas LL8 (Vortec 4200) has also been terminated. The smaller I4 and I5 variants are still produced.
| Also called | Vortec 3500 |
|---|---|
| Displacement | 3,460 cc (211 cu in) |
| Cylinder bore | 93 mm (3.7 in) |
| Piston stroke | 102 mm (4.0 in) |
| Power output | 220 hp (164 kW) at 5600 RPM |
| Torque output | 225 lb·ft (305 N·m) at 2800 RPM |
The L52 (also called Vortec 3500), is a straight-5 truck engine. It displaces 3.5 L (3,460 cc/211 cu in), with a 93 mm (3.7 in) bore and 102 mm (4.0 in) stroke, and shares much with the rest of the Atlas family. Dynoed at the flywheel it produces 220 hp (164 kW) at 5600 rpm and 225 ft·lbf (305 N·m) at 2800 rpm, while producing 179.13 hp at 6001 rpm when dynoed at the rear wheels. Engine redline is 6300 rpm. These engines have a known issue: The valve seats of the intake valves allow some exhaust gasses to travel back out the intake valve, causing a misfire condition. GM issued a recall to replace the cylinder heads on models triggering the specific problem code.
It is used in the following vehicles:
The LLR (also called Vortec 3700), is a straight-5 truck engine. It displaces 3.7 L (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, and shares much with the rest of the Atlas family. It produces 242 hp (180 kW) at 5600 rpm and 242 ft·lbf (327 N·m) at 4600 rpm. Engine redline is 6300 rpm.
It is used in the following vehicles:
The straight-4 LK5 engine is sold as the Vortec 2800 in GM trucks. Like its Atlas brothers, the LK5 has dual overhead cams, and shares their 93 mm (3.7 in) bore and 102 mm (4.0 in) stroke. The LK5 displaces 2.8 L (2770 cc, 169 cu in) and produces 175 hp (131 kW) at 5600 rpm and 185 ft·lbf (251 N·m) at 2800 rpm.[2] Engine redline is 6300 rpm.
It is used in the following vehicles:
The straight-4 LLV engine is sold as the Vortec 2900 in GM trucks. It shares the same 95.5 mm bore and 102 mm (4.0 in) stroke as the LLR Vortec 3700. The LLV displaces 2.9 L (2921 cc, 178 cu in)[3] and produces 185 hp (138 kW) at 5600 rpm and 190 ft·lbf (258 N·m) at 2800 rpm. Engine redline is 6300 rpm.
It is used in the following vehicles: