The GM / Chevy L33 HO is a 5.3 l (325 cu.in.) natural aspirated V8 90° four-stroke gasoline engine from a Generation III small block V8 truck engine series. The L33 engine is an aluminum block version of the LM7 and it was produced from 2005 to 2007. The L33 engine with VIN code “B” is also called the Vortec 5300 HO.
The GM L33 features V8 90° aluminum cylinder block with a five-bearings crankshaft, two aluminum heads, single one-piece cast camshaft and two valves per cylinder (16 in total).
The L33 has a sequential multi-port fuel injection system and a 78.0 mm electronic throttle body. The engine used “Coil-Near-Plugs” ignition system with a composite distributor, low-resistance spark plug wires and platinum-tipped spark plugs.
Compression ratio rating is 9.9:1. Cylinder bore and piston stroke are 96.0 mm (3.78 in) and 92.0 mm (3.62 in), respectively. The engine produces 313 PS (230 kW; 310 HP) at 5,200 rpm. The L33 Vortec 5.3 HO has a torque rating of 441 Nm (45 kg·m; 325 ft·lb) at 4,000 rpm.
|Engine code||GM / Chevy L33 (Vortec 5300 HO)|
|Layout||Four stroke, V8|
|Fuel type||Gasoline (petrol)|
|Displacement||5.3 L, (325 cu in)|
|Fuel system||Sequential multi-port fuel injection|
|Power output||313 PS (230 kW; 310 HP) at 5,200 rpm|
|Torque output||441 Nm (45 kg·m; 325 ft·lb) at 4,000 rpm|
|Dimensions (L x W x H):||–|
The GM L33 Vortec has an aluminum 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 compression ratio rating is 9.9:1. The GM LM4 motor has two compression and one oil control rings. The connecting rod’s length is 154.89 mm (6.098 in). The L33 motor uses a flat top piston from the LR4 Vortec 4.8L instead of the dish piston found in the LM7.
|Cylinder block alloy||Aluminum|
|Cylinder bore:||96.0 mm (3.78 in)|
|Piston stroke:||92.0 mm (3.62 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:||23.950-23.957 mm (0.9429-0.9431 in)|
|Piston ring side clearance:||Top||0.045-0.080 mm (0.0018-0.0031 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)|
|Connecting rod center distance:||159.38 mm (6.275 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)|
|Crankshaft center distance:||46 mm (1.81 in)|
The cylinder heads are made of strong, light aluminum alloy which gives it good cooling efficiency. It L33 Vortec 5.3 HO uses 799 cylinder heads, which are identical to the 243 castings. 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.
The intake valve diameter is 50.8 mm (2.000 in) and the exhaust valve diameter is 39.4 mm (1.55 in), respectively. The intake duration is 193°, and the intake valve lift is 12.24 mm (0.482 in), the exhaust duration is 193°, the exhaust valve lift is 12.24 mm (0.482 in). The lobe separation angle is 116°.
|Block head alloy||Aluminium|
|Valve Arrangement:||OHV, chain drive|
|Valves:||16 (2 valves per cylinder)|
|Intake valve timing:||193°|
|Exhaust valve timing:||193°|
|Valve head diameter:||INTAKE||12.24 mm (0.482 in)|
|EXHAUST||39.4 mm (1.5512 in)|
|Valve stem diameter:||INTAKE||–|
|Valve spring free length:||INTAKE||–|
|Camshaft lobe lift:||INTAKE||7.20 mm (0.283 in)|
|EXHAUST||7.20 mm (0.283 in)|
|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 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)||5.7 L (6.02 US. qt, 5.02 Imp. qt.)|
|Oil change interval, km (miles)||12,000 km (7,500 miles)|
41 kPa at 1,000 rpm|
124 kPa at 2,000 rpm
165 kPa at 4,000 rpm
|Spark plug||AC Delco: 41-985 Iridium|
|Spark plug gap||1.01 mm (0.0398 in)|
|Chevrolet Silverado 1500 4WD||2005–2007|
|GMC Sierra 1500 4WD||2005–2007|