GM / Chevy LMG Vortec 5300

The GM / Chevy LMG (VIN – “0”) is a 5.3 l (325 cu.in.) natural aspirated V8 90° four-stroke flex fuel engine from the GM Generation IV small block V8 truck engine series. This engine was manufactured in Romulus, Michigan, USA and Silao, Mexico from 2007 to 2014.

The GM LMG Vortec 5300 features a V8 90° cast-iron cylinder block with a five-bearings crankshaft, two aluminum heads, a single one-piece cast camshaft, and two valves per cylinder (16 in total). The LMG has a sequential multi-port fuel injection system with an active fuel management system and an 87.0 mm throttle body with electronic throttle control. The engine used a “Coil-Near-Plugs” ignition system and Variable Valve Timing (VVT) system from 2010. The redline is 6,000 rpm.

The compression ratio rating was 9.9:1 from 2007 to 2009, and 9.6:1 after 2010. Cylinder bore and piston stroke are 96.0 mm (3.78 in) and 92.0 mm (3.62 in), respectively. The engine produced 314 PS (231 KW; 310 HP) at 5,400 rpm or 325 PS (239 KW; 320 HP) at 5,400 rpm on regular unleaded fuel or 330 PS (243 KW; 326 HP) at 5,300 rpm on E85 Flex Fuel. The engine has a torque rating 454 Nm (46.3 kg·m; 335.0 ft·lb) at 4,000 rpm on regular unleaded fuel and 472 Nm (48.14 kg·m; 348.34 ft·lb) at 4,400 rpm on E85 Flex Fuel.

General information

Cylinder block

The GM LMG has a cast-iron cylinder block with a five-bearings crankshaft supported system. The crankshaft journal diameter is 65.0 mm (2.55 in), the crankpin diameter is 53.3 mm (2.09 in).

The cylinder bore is 96.0 mm (3.78 in), piston stroke is 92.0 mm (3.62 in), and the compression ratio rating was 9.9:1 (2007-2009) or 9.6:1 (2010-2014). The GM LMG motor has two compression and one oil control rings. The engine used the flat top pistons (2007-2009) or flat top with valve reliefs (since 2010).

Cylinder head

The cylinder heads are made of strong, light aluminum alloy which gives it good cooling efficiency. The camshaft is driven by a single chain. The timing chain transmits the rotational movement from the crankshaft to the camshafts. Valves are operated via pedestal mounting rocker arms.

Head tightening procedure and torque specs:
M8 bolts:

• 30 Nm (3.06 kg·m; 22.14 ft·lb)

M11 bolts:

• Step 1: 30 Nm (3.06 kg·m; 22.14 ft·lb)
• Step 2: Turn all bolts: 90°
• Step 3: Turn all bolts: 70°

Maintenance data

Vehicle applications

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