GM / Chevy LR4 Vortec 4800

GM / Chevy LR4 Vortec 4800 engineThe GM / Chevy LR4 VORTEC 4800 is a 4.8 L (292 cu·in) natural aspirated V8 four-stroke liquid-cooled internal combustion gasoline engine, manufactured by General Motors since 1999 to 2006. The LR4 (VIN code “V”) is the smallest engine of the Generation III Vortec truck engines. The engine was manufactured at St. Catharines, Ontario, USA and Romulus, Michigan, USA.

The GM / Chevy LR4 engine has a V8 cast-iron block, two aluminum heads with 16 overhead valves (OHV), and a single camshaft. This engine used a sequential fuel injection system and “Coil-Near-Plugs” ignition system and wet sump lubricating system. The engine is equipped with 78.0 mm (3.07 in) 3-bolts mounted throttle body. From 1999 to 2000, the LR4 Vortec 4800 engine was equipped with the EGR system; on engines after 2002 this system was not installed.

The GM / Chevy LR4 engine produced:

  • In 1999 it produced 258 PS (190 kW; 255 HP) of peak horsepower
  • After 2000 and above models made from 273 PS (201 kW; 270 HP) to 290 PS (213 kW; 285 HP) of output power and a torque rating between 386 Nm (39.4 kg·m; 284.9 ft·lb) and 400 Nm (40.8 kg·m; 295.2 ft·lb), depending on the model year and application
  • The 2005-2006 models produces 290 PS (213 kW; 285 HP) of horsepower and 400 Nm (40.8 kg·m; 295.2 ft·lb) of peak torque

General information

Engine Specifications
Engine model GM / Chevy LR4 Vortec 4800
Production 1999-2006
Engine type 4-stroke, V8, OHV, chain driven
Displacement 4.8 L, (293 CID)
Max. horsepower 258 PS (190 kW; 255 HP)
273 PS (201 kW; 270 HP)
290 PS (213 kW; 285 HP)
Max. torque 386 Nm (39.4 kg·m; 284.9 ft·lb)
400 Nm (40.8 kg·m; 295.2 ft·lb)
Ignition system Coil-Near-Plugs
Fuel system Sequential 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 83.0 mm (3.27 in) piston stroke give the LR4 engine a total of 4.8 L (293 CID) of displacement. The compression ratio rating is 9.4:1. The engine used a cast-iron cylinder block with 111.76 mm (4.40 in) of bore spacing. The Vortec 4800 is equipped with flat top pistons which are made of cast aluminum alloy and powdered metal I-beam style connecting rods. The connecting rod’s length is 159.38 mm (6.275 in). Each piston is fitted with two compression rings and a single oil ring.

Cylinder block
Cylinder block alloy Cast-iron
Compression ratio: 9.4:1
Cylinder bore: 96.0 mm (3.78 in)
Piston stroke: 83.0 mm (3.27 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: 23.997-24.000 mm (0.9448-0.9449 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: 41.5 mm (1.635 in)

Cylinder Head

The LR4 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 a 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 LR4, 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: 1999: 2.742 gm/sec (21.8 lb/hr) at 58 psi
2000 : 3.125 gm/sec (24.8 lb/hr) at 58 psi
2001-2006: 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 Silverado 1500 1999-2006
Chevrolet Tahoe 2000-2006
Chevrolet Express 2003-2006
GMC Sierra 1500 1999-2006
GMC Yukon 2000-2006
GMC Savana 2003-2006

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