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Chevrolet LM7 Specifications
| Engine Model: Chevrolet LM7 (Vortec 5300) |
| Engine Type: 4-cycle 8-cylinder OHV 16-valve liquid-cooled gasoline |
| Total Displacement: 325.1 cu.in (5.33 L) |
| Rated Engine Power: 285-290 Hp (213-216 kW) at 5200 rpm |
| Fuel System Type: Sequential port fuel injection (SFI) |
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| General Technical Data |
The Chevrolet LM7, marketed as the Vortec 5300,
is a 5.3-liter, V8, naturally aspirated gasoline engine. It is a central
member of General Motors' Generation III Small Block V8 family, commonly
referred to as the LS-based truck engine series. Manufactured from 1999
through 2007, this engine was engineered for longitudinal installation
in full-size pickup trucks, sport utility vehicles, and vans. Its design
philosophy focused on providing a robust combination of power, torque,
reliability, and manufacturing efficiency.
The LM7 employs a pushrod (OHV) valvetrain with two valves per cylinder
and features aluminum cylinder heads with cathedral-shaped intake ports.
A sequential fuel injection (SFI) system controls fuel delivery. This
engine is recognized for its widespread use, strong aftermarket support,
and durable construction, serving as a primary V8 powerplant for GM's
truck and SUV lineup for nearly a decade.
Engine Type: 90-degree V8, gasoline, overhead valve (OHV/pushrod)
Displacement: 5328 cc (325.1 cubic inches)
Bore: 96.0 mm (3.780 inches)
Stroke: 92.0 mm (3.622 inches)
Compression Ratio: 9.5:1
Firing Order: 1-8-7-2-6-5-4-3
Cylinder Numbering: Left bank (driver side): 1-3-5-7; Right bank
(passenger side): 2-4-6-8
Maximum Power Output: 213-216 kW (285-290 Hp) at 5200 rpm
Maximum Torque: 434-441 Nm (320-325 lb-ft) at 4000 rpm
Fuel Type: Unleaded gasoline, 87 AKI (91 RON) minimum
Oil Quality Specification: API SL or newer, GM Standard GM6094M
Engine Oil Capacity (including filter): 5.7 liters (6.0 US quarts)
Coolant Capacity (total system): 13.2 liters (13.95 US quarts)
| Cylinder Block |
The LM7 uses a cast iron cylinder block. This block features six-bolt main bearing caps (two vertical and two cross-bolts per cap) which provide exceptional rigidity and crankshaft stability. The crankshaft is a nodular iron casting with induction-hardened journals. The cylinder bores are machined directly into the iron casting without the use of liners.
Connecting rods are powdered metal units with fractured-cap big ends for precise bearing alignment. Pistons are hypereutectic aluminum alloy, designed for low friction and controlled expansion, and are fitted with two low-tension compression rings and a three-piece oil control ring. The camshaft is located centrally in the block's valley, operating the valves via pushrods.
| Cylinder Head and Valves |
The LM7 is equipped with aluminum alloy cylinder heads. These heads feature a cathedral-shaped intake port and a corresponding combustion chamber designed for efficient airflow within the two-valve-per-cylinder architecture. Each cylinder operates with a single intake and a single exhaust valve.
The valves are actuated by hydraulic roller lifters, pushrods, and stamped steel rocker arms with a ratio of 1.7:1. Valve springs are beehive-shaped to reduce mass and dampen harmonic vibrations. The head gaskets are composite graphite material. The cylinder heads are secured with six bolts per cylinder.
| Fuel System |
Fuel delivery is managed by a sequential port fuel injection (SFI) system. The system utilizes a returnless fuel supply with an electric in-tank fuel pump. A fuel rail supplies eight individual injectors, one for each cylinder. Fuel pressure is regulated within the tank module.
The system is controlled by a 32-bit PCM (Powertrain Control Module). This PCM receives inputs from sensors including a mass air flow (MAF) sensor, throttle position sensor (TPS), manifold absolute pressure (MAP) sensor, and dual heated oxygen sensors. The throttle body is electronically controlled (drive-by-wire) on later models.
| Lubrication System |
Lubrication is provided by a gerotor-style oil pump, mounted to the front of the block and driven directly by the crankshaft. The system is a high-volume, high-pressure design. Oil is drawn from a baffled oil pan, pressurized, and forced through a full-flow spin-on oil filter.
From the filter, oil travels through a dedicated gallery to the main oil gallery, feeding the crankshaft main and connecting rod bearings, the camshaft bearings, and the lifters. A separate passage feeds oil through the hollow pushrods to lubricate the rocker arms and valve stems. A pressure relief valve is integrated into the oil pump housing.
| Cooling System |
Coolant circulation is handled by a belt-driven water pump. The system is regulated by a 195°F (91°C) wax-type thermostat, housed in the thermostat housing at the front of the intake manifold. Coolant flows from the pump through passages in the block, then up into the cylinder heads, and finally to the aluminum cross-flow radiator.
A mechanical engine cooling fan, mounted to a viscous clutch drive, provides airflow. The fan clutch engagement is controlled by a bi-metallic coil that responds to under-hood air temperature. A pressurized coolant recovery reservoir serves as the fill point and expansion tank.
| Intake and Exhaust Systems |
The intake manifold is a composite plastic design, chosen for weight savings and thermal insulation to keep intake air charge cool. The exhaust manifolds are cast iron units. The exhaust system is a dual-bank setup, merging into a single pipe after the catalytic converters.
The system includes two pre-catalytic converters (one per bank) mounted close to the exhaust manifolds and a main underbody catalytic converter. An Exhaust Gas Recirculation (EGR) system is used to reduce nitrogen oxide (NOx) emissions.
| Ignition System |
The engine uses a distributorless coil-near-plug ignition system. Eight individual ignition coils, mounted directly on the valve covers, fire each spark plug via short boots. The PCM controls ignition timing for each cylinder independently based on inputs from the crankshaft position (CKP) and camshaft position (CMP) sensors. The system uses platinum-tipped spark plugs with a recommended service interval of 100,000 miles (160,000 km).
| Engine Control and Electronics |
The engine management system is integrated into the vehicle's Powertrain Control Module (PCM). This unit controls fuel injection, ignition timing, variable exhaust valve timing (on certain late models), and emissions systems. The PCM communicates via a Class 2 serial data bus. The throttle is electronically controlled via an accelerator pedal position (APP) sensor.
| Dimensions and Weight |
Length (from bellhousing to water pump pulley): 780 mm (30.71 inches)
Width (across exhaust manifolds): 760 mm (29.92 inches)
Height (from oil pan to intake manifold): 740 mm (29.13 inches)
Dry Weight (without accessories): 210 kg (463 lbs)
| Maintenance Data |
Recommended Service Intervals:
Engine Oil and Filter Change: 12000 km (7500 miles) or 12 months under
normal service conditions.
Air Filter Element Replacement: 48000 km (30000 miles) or as required.
Spark Plug Replacement: 160000 km (100000 miles).
Coolant Replacement: 240000 km (150000 miles) or 5 years with Dex-Cool.
Serpentine Drive Belt Inspection: Check at oil change; replace per
condition or at 160000 km (100000 miles).
Fuel Filter Replacement: Service interval varies; often recommended at
48000 km (30000 miles).
Fluid Specifications and Capacities:
Engine Oil: SAE 5W-30, meeting GM Standard GM6094M.
Cooling Fluid: Dex-Cool or equivalent OAT (Organic Acid Technology)
coolant.
Automatic Transmission Fluid: Dexron III or VI as specified.
| Tightening Torques |
Cylinder Head Bolts: Torque-to-yield, single-use bolts. Tighten in three
stages using the proper sequence.
Step 1: 30 Nm (22 lb-ft)
Step 2: Tighten an additional 90 deg of rotation
Step 3: Tighten an additional 90 deg of rotation
Main Bearing Cap Bolts (vertical): 50 Nm (37 lb-ft) plus an additional
77 deg
Main Bearing Cap Cross-Bolts: 20 Nm (15 lb-ft) plus an additional 50 deg
Connecting Rod Cap Bolts: 25 Nm (18 lb-ft) plus an additional 85 deg
(lubricate threads)
Spark Plugs: 15 Nm (11 lb-ft)
Oil Pan Bolts: 25 Nm (18 lb-ft)
Oil Filter: Tighten by hand three-quarters turn after gasket contact
Crankshaft Balancer Bolt: 110 Nm (81 lb-ft) plus an additional 140 deg
Intake Manifold Bolts: 10 Nm (89 pound-inches) for perimeter bolts; 25
Nm (18 lb-ft) for center bolts.
| Vehicle Applications |
The Chevrolet LM7 Vortec 5300 engine was
installed in the following vehicles (2000-2007 model years):
Chevrolet Silverado 1500
GMC Sierra 1500
Chevrolet Tahoe
GMC Yukon
Chevrolet Suburban
GMC Yukon XL
Chevrolet Avalanche
Cadillac Escalade (2002-2006)
Chevrolet Express 1500
GMC Savana 1500
Hummer H2
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