Is that a modern straight six? Educate us, please. What kind of vehicle do those come in?
From Wikipedia, the free encyclopedia
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,
[1] 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.
[2]
The Atlas engines feature aluminum cylinder blocks and heads, with the cylinder bores featuring replaceable steel
cylinder liners.
[1] The 4- and 5-cylinder versions feature dual balance shafts,
[3][4] balance shafts being unnecessary in the 6-cylinder.
[5]
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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2006 LL8 (Vortec 4200) engine in 2006 Chevrolet TrailBlazer
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 4.2 L (4,160 cc; 253.9 cu in), 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 6,000
rpm and torque was 275 lb⋅ft (373 N⋅m) at 3,600 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 6,000 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. 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.
[6]
Applications:
