The Specifications of a Chevrolet 4.2 Liter Inline 6 Cylinder Engine

by Justin Cupler
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The 4.2-liter Chevrolet engine was placed in the 2002 through 2009 Chevy TrailBlazer. This engine was the replacement for the aged 4.3-liter V-6 engine. The 4.2-liter--like the 4.3-liter before it--is a member of the Vortec family of engines. Vortec is Chevrolet's version of variable-valve timing. When the TrailBlazer was eliminated from Chevrolet's lineup in 2010, the 4.2-liter was eliminated with it.


The 4.2-liter engine is an inline six-cylinder (I-6) and is powered by regular gasoline. It has 24 valves--four valves per cylinder--and they are in a double-overhead-cam (DOHC) configuration. This means that there are two camshafts and they sit on the top of the cylinder head.


Throughout its production life, it had a bore (cylinder width) of 3.66 inches and a stroke (distance the piston travels inside the cylinder) of 4.01 inches, except in 2003, when it was 4.02 inches. The overall displacement was 4,195 cubic centimeters in 2002 and 2003; the displacement shrank to 4,161 cubic centimeters from 2004 through 2009. The compression ratio ranged from 10:1 to 10.3:1, depending on the model year.


In its debut year, 2001, the 4.2-liter produced 270 horsepower at 6,000 rpm and 275 foot-pounds of torque at 3,600 rpm. From 2003 through 2005, there was a small increase to 275 horsepower at 6,000 rpm and 275 foot-pounds of torque at 3,600 rpm. The 4.2-liter I-6 produced 291 horsepower at 6,000 rpm and 277 foot-pounds of torque at 4,800 rpm in 2006 and 2007. Finally, in its last two years--2008 and 2009--there was a small decrease in power to 285 horsepower at 6,000 rpm and 276 foot-pounds of torque at 4,600 rpm.


As always, fuel economy is a concern in all newer engines. The 4.2-liter I-6 got 15 to 16 mpg in the city and 21 to 22 mpg on the highway, depending on the model year.

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