GM / Chevy LM4 Vortec 5300

GM / Chevy LM4 Vortec 5300 engineThe GM / Chevy LM4 Vortec 5300 is a 5.3 L (5,328 cc, 325.13 cu·in) natural aspirated V8 four-stroke liquid-cooled internal combustion gasoline engine, manufactured by General Motors. The GM LM4 engine (VIN code “P”) was introduced in 2003 as a lightweight version of the LM7, and it was available in GM SUVs until 2005.

The GM / Chevy LM4 engine has a V8 lightweight aluminum cast block, two aluminum heads with 16 overhead valves (OHV), and a single camshaft. This engine used a sequential multi-port fuel injection system and “Coil-Near-Plugs” ignition system with a composite distributor and pressurized lubricating system with a wet sump. The engine is equipped with return style (2003) or returnless (2004-2005) fuel rail and 78.0 mm electronic (Drive-by-Wire) throttle.

The LM4 engine produced from 294 PS (216 kW; 290 HP)at 5,200 rpm to 304 PS (224 kW; 300 HP) at 5,200 rpm of maximum horsepower and from 441 N·m (45.0 kg·m, 325 ft·lb) at 4,000 rpm to 454 N·m (46.3 kg·m, 335 ft·lb) at 4,000 rpm of peak torque.

General information

Engine Specifications
Engine model GM / Chevy LM4 Vortec 5300
Production 2003-2005
Engine type 4-stroke, V8, OHV, chain driven
Displacement 5.3 L (5,328 cm3, 325.13 cu·in)
Max. horsepower 294 PS (216 kW; 290 HP)at 5,200 rpm
304 PS (224 kW; 300 HP) at 5,200 rpm
Max. torque 441 N·m (45.0 kg·m, 325 ft·lb) at 4,000 rpm
454 N·m (46.3 kg·m, 335 ft·lb) at 4,000 rpm
Ignition system Coil-Near-Plugs
Fuel system Sequential multi-port fuel injection
Power adder None
Firing order 1-8-7-2-6-5-4-3
Cooling system Liquid-cooled
Lubricating system Wet sump

Cylinder Block

A 96.0 mm (3.78 in) cylinder bore and 92.0 mm (3.62 in) piston stroke give the LM4 engine a total of 5.3 L (325 CID) of displacement. The compression ratio rating is 9.5:1. The engine used an aluminum cylinder block with iron cylinder sleeves and 11.76 mm (4.40 in) of bore spacing. The Vortec 5300 LM4 is equipped with dish pistons that are made of cast aluminum alloy and powdered metal I-beam style connecting rods. The connecting rod’s length is 154.89 mm (6.098 in). Each piston is fitted with two compression rings and a single oil ring.

Cylinder block
Cylinder block alloy Aluminium
Compression ratio: 9.5:1
Cylinder bore: 96.0 mm (3.78 in)
Piston stroke: 92.0 mm (3.62 in)
Cylinder internal diameter (standard): 96.000-96.018 mm (3.7795-3.7802 in)
Piston skirt outer diameter (standard): 96.000 mm (3.7795 in)
Number of piston rings (compression / oil): 2/1
Connecting rod big end diameter (standard): 56.505-56.525 mm (2.2246-2.2254 in)
Connecting rod small end diameter (standard): 24.000 mm (0.9449 in)
Piston pin diameter: 2003-2004: (Pressed)
23.997-24.000 mm (0.9448-0.9449 in)
2005: (Floating)
23.950-23.957 mm (0.9429-0.9431 in)
Side clearance (Top): 0.040-0.085 mm (0.0016-0.0033 in)
Side clearance (Second): 0.040-0.078 mm (0.0016-0.0031 in)
Side clearance (Oil): 0.012-0.200 mm (0.0005-0.0079 in)
Ring end gap (Top): 0.230-0.440 mm (0.0091-0.0173 in)
Ring end gap (Second): 0.440-0.700 mm (0.0173-0.0276 in)
Ring end gap (Oil): 0.180-0.750 mm (0.0071-0.0295 in)
Number of main bearings: 5
Crankshaft main journal diameter: 64.993-65.007 mm (2.5588-2.5593 in)
Crankpin journal diameter: 53.318-53.338 mm (2.0991-2.0999 in)
Crankshaft center distance: 46 mm (1.81 in)

Cylinder Head

The GM / Chevy LM4 engine has two aluminum heads with 2 valves per cylinder (16 in total) and a single camshaft driven by the crankshaft via a chain. The intake port has a cathedral shape with 200 cc intake runner volume and the exhaust has an oval shape with 70 cc exhaust runner volume. Intake and exhaust valves era made of steel with a solid stem. Valves are operated via pedestal mounting rocker arms.

Cylinder head
Cylinder head alloy Aluminium
Valve arrangement: OHV, chain driven
Valves:: 2 (16 valves in total)
Head height: 120.2 mm (4.7323 in)
Intake timig: 191°
Exhaust timig: 190°
Valve lift (INTAKE): 11.60 mm (0.457 in)
Valve lift (EXHAUST): 11.84 mm (0.466 in)
Valve head diameter (INTAKE): 48.0 mm (1.8898 in)
Valve head diameter (EXHAUST): 39.4 mm (1.5512 in)
Valve steam diameter (INTAKE): 7.955-7.976 mm (0.3132-0.314 in)
Valve steam diameter (EXHAUST): 7.955-7.976 mm (0.3132-0.314 in)
Valve spring free length (INTAKE): 52.9 mm (2.0827 in)
Valve spring free length (EXHAUST): 52.9 mm (2.0827 in)
Camshaft lobe lift (INTAKE): 6.96 mm (0.274 in)
Camshaft lobe lift (EXHAUST): 6.82 mm (0.2685 in)
Camshaft journal diameter : 54.99-55.04 mm (2.165-2.1669 in)

Tightening torque

Tightening torque settings
Connecting rod bolts Step 1: 20 Nm (2.04 kg·m; 14.76 ft·lb)
Step 2: Turn all bolts: 70°
Crankshaft bearing cap bolts Step 1: 20 Nm (2.04 kg·m; 14.76 ft·lb)
Step 2: Turn inner bolts: 80° turn outer bolts: 51°
Flywheel bolts Step 1: 20 Nm (2.04 kg·m; 14.76 ft·lb)
Step 2: 50 Nm (5.1 kg·m; 36.9 ft·lb)
Step 3: 100 Nm (10.2 kg·m; 73.8 ft·lb)
Cylinder head bolts Step 1: 30 Nm (3.06 kg·m; 22.14 ft·lb)
Step 2: Turn all bolts: 90°
Step 3: Turn all bolts excluding the medium length bolts at the front and rear of each head: 90°
Step 4: Turn all medium length bolts at the front and rear of each head: 50°
Valve rocker arm bolts 30 Nm (3.06 kg·m; 22.14 ft·lb)

Service Data

The engine oil with a viscosity of 5W-30 is recommended for the LM4, refilling oil capacity is 5.7 L (6.02 US. qt, 5.02 Imp. qt.). A recommended spark plug is AC Delco 41-985 Iridium with 1.01 mm (0.0398 in) spark plug gap.

Oil system
Lubrication system: Wet sump
Oil type: 5W-30
Oil capacity: 5.7 L (6.02 US. qt, 5.02 Imp. qt.)
Oil change interval: 12,000 km (7,500 miles)
Fuel system
Type: Sequential multi-port fuel injection
Fuel Injector Flow: 3.180 gm/sec (25.2 lb/hr) at 58 psi
Ignition system
Type: Coil-Near-Plugs
Spark plug: AC Delco 41-985 Iridium
Spark plug gap: 1.01 mm (0.03980.0398 in)
Spark plug torque: 15 N·m (1.5 kg·m, 11.1 ft·lb)

Applications

Model Years Produced
Chevrolet Trailblazer EXT 2003-2005
Chevrolet SSR 2003-2004
GMC Envoy XL 2003-2004
Buick Rainier 2004
Isuzu Ascender 2003-2004

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