The GM / Chevy LY2 (VIN – “C”) is a 4.8 l (293 cu.in.) natural aspirated V8 90° four-stroke gasoline engine from a Generation IV small-block V8 truck engine series. The engine was manufactured from 2007 to 2009.
The GM LY2 Vortec 4800 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 LY2 used a sequential multi-port fuel injection system and 84.0 mm (3.31 in) throttle body with electronic (Drive-by-Wire) control and coil-near-plugs ignition system with iridium spark plugs and low resistance spark plug wires
The compression ratio rating is 9.1:1. Cylinder bore and piston stroke are 96.0 mm (3.78 in) and 83.0 mm (3.27 in), respectively. The engine produced from 264 PS (194 kW; 260 HP) to 300 PS (220 kW; 295 HP). The maximum torque is from 400 N·m (40.8 kg·m, 294.8 ft·lb) to 414 N·m (42.2 kg·m, 305.1 ft·lb).
General information
| Engine Specifications | |
| Engine code | GM / Chevy LY2 Vortec 4800 |
| Layout | Four stroke, V8 |
| Fuel type | Gasoline (petrol) |
| Production | 2007-2009 |
| Displacement | 4.8 L, (293 cu in) |
| Fuel system | Sequential fuel injection |
| Power adder | None |
| Power output |
From 264 PS (194 kW; 260 HP) to 300 PS (220 kW; 295 HP) |
| Torque output |
From 400 N·m (40.8 kg·m, 294.8 ft·lb) to 414 N·m (42.2 kg·m, 305.1 ft·lb) |
| Firing order | 1-8-7-2-6-5-4-3 |
| Dimensions (L x W x H): | – |
| Weight | – |
Cylinder block
The LY2 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 crankshaft is a cast nodular iron.
The cylinder bore is 96.0 mm (3.78 in), piston stroke is 83.0 mm (3.27 in) and the compression ratio rating is 9.1:1. The GM LY2 motor has two compression and one oil control rings. The pistons are cast aluminum. The piston pins are chromium steel and are a full-floating design. The connecting rods are powdered metal.
| Cylinder block | ||
| Cylinder block alloy | Cast-iron | |
| Compression ratio: | 9.1:1 | |
| Cylinder bore: | 96.0 mm (3.78 in) | |
| Piston stroke: | 83.0 mm (3.27 in) | |
| Number of piston rings (compression / oil): | 2 / 1 | |
| Number of main bearings: | 5 | |
| Cylinder inner diameter (standard): | 96.000-96.018 mm (3.7795-3.7802 in) | |
| Piston skirt diameter (standard): | 96.000 mm (3.7795 in) | |
| Piston pin outer diameter: | 23.952-23.955 mm (0.943-0.9431 in) | |
| Piston ring side clearance: | Top | 0.040-0.085 mm (0.0016-0.0033 in) |
| Second | 0.040-0.078 mm (0.0016-0.0031 in) | |
| Oil | 0.012-0.200 mm (0.0005-0.0079 in) | |
| Piston ring end gap: | Top | 0.23-0.44 mm (0.0091-0.0173 in) |
| Second | 0.44-0.70 mm (0.0173-0.0276 in) | |
| Oil | 0.18-0.75 mm (0.0071-0.0295 in) | |
| Connecting rod small end diameter | 24.000 mm (0.9449 in) | |
| Connecting rod big end diameter: | 56.505-56.525 mm (2.2246-2.2254 in) | |
| Crankshaft main journal diameter: | 64.993-65.007 mm (2.5588-2.5593 in) | |
| Crankpin diameter: | 53.318-53.338 mm (2.0991-2.0999 in) | |
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.
| Cylinder head | ||
| Block head alloy | Aluminium | |
| Valve Arrangement: | OHV, chain drive | |
| Valves: | 16 (2 valves per cylinder) | |
| Intake valve timing: | 191° | |
| Exhaust valve timing: | 190° | |
| Valve head diameter: | INTAKE | – |
| EXHAUST | – | |
| Valve length: | INTAKE | – |
| EXHAUST | – | |
| Valve stem diameter: | INTAKE | 7.955-7.976 mm (0.3132-0.314 in) |
| EXHAUST | 7.955-7.976 mm (0.3132-0.314 in) | |
| Valve spring free length: | INTAKE | 52.9 mm (2.0827 in) |
| EXHAUST | 52.9 mm (2.0827 in) | |
| Camshaft lobe lift: | INTAKE | 7.2 mm (0.2835 in) |
| EXHAUST | 7.2 mm (0.2835 in) | |
| Camshaft journal diameter: | 54.99-55.04 mm (2.165-2.1669 in) | |
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
| Compression pressure | |
| Standard | 12.5 kg/m2 / 300 rpm |
| Minimun | 7.0 kg/m2 / 300 rpm |
| Compression differential limit between cylinders | 1.0 kg/m2 (15 psi) / 300 rpm |
| Oil system | |
| Oil consumption , L/1000 km (qt. per miles) | up to 0.5 (1 qt. per 1200 miles) |
| Recommended engine oil | 5W-30, 10W-30 |
| Oil type API | – |
| Engine oil capacity (Refill capacity) |
Without oil filter: 5.2 L (5.5 US. qt, 4.6 Imp. qt.) With oil filter: 5.7 L (6.0 US. qt, 5.00 Imp. qt.) |
| Oil change interval, km (miles) | 12,000 km (7,500 miles) |
| Oil Pressure |
41 kPa at 1,000 rpm 124 kPa at 2,000 rpm 165 kPa at 4,000 rpm |
| Ignition system | |
| Spark plug | AC Delco: 41-985 Iridium |
| Spark plug gap | 1.01 mm (0.0398 in) |
Vehicle applications
| Model | Years Produced |
| Chevrolet Express | 2008–2009 |
| Chevrolet Silverado | 2007–2009 |
| Chevrolet Tahoe | 2007–2009 |
| GMC Sierra | 2007–2009 |
| GMC Yukon | 2007–2009 |
| GMC Savana | 2008–2009 |
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