Honda J30A4 Specifications
| Engine Model: Honda J30A4 |
| Engine Type: 4-cycle 6-cylinder SOHC 24-valve i-VTEC liquid-cooled gasoline |
| Total Displacement: 182.9 cu.in (2.99 L) |
| Rated Engine Power: 240-244 Hp (179-182 kW) at 6200 rpm |
| Fuel System Type: Sequential multi-point fuel injection (PGM-FI) |
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The Honda J30A4 is a 3.0-liter V6 engine from
Honda’s J-series family, engineered for smooth, refined, and efficient
performance in midsize sedans and crossovers during the mid-2000s. Used
mainly in the Honda Accord V6 and select Acura models, the J30A4
represents an evolution of the earlier J30A1 with improvements in
emissions control, combustion efficiency, ignition control, and
electronic throttle management.
The J30A4 maintains Honda’s philosophy of designing lightweight, durable
aluminum engines with reliable SOHC valvetrains, efficient combustion
chambers, and smooth power delivery. Owners often praise the J30A4 for
its long service life, stable torque output, quiet operation, and
predictable maintenance needs. With routine servicing, this engine can
comfortably exceed high mileage with minimal internal wear, making it
one of the most robust and efficient engines from Honda’s mid-2000s
lineup.
The Honda J30A4 is a four-stroke, liquid-cooled, 60-degree V6 gasoline
engine with a displacement of 2,997 cc (182.9 cubic inches). Bore
measures 86.0 mm (3.39 inches), stroke is 86.0 mm (3.39 inches), and the
compression ratio is approximately 10.0:1. This square geometry allows
balanced torque characteristics while maintaining smooth high-rpm
operation.
Factory output varies slightly by model and
market but includes:
– Power: approx. 240–244 horsepower (179–182 kW) at 6,200 rpm
– Torque: approx. 287–290 Nm (212–214 lb-ft) at ~5,000 rpm
– Idle speed: approx. 680 ± 50 rpm
– Rev limiter: approx. 6,700 rpm
The engine uses a forged steel crankshaft supported by four main
bearings, forged steel connecting rods, and cast-aluminum pistons with
low-friction molybdenum coatings. It employs Honda’s i-VTEC system on
the intake camshaft and uses PGM-FI electronic fuel injection for
precise delivery and efficient combustion.
The J30A4 uses an open-deck aluminum cylinder block with centrifugally
cast-iron liners for durability. The 60-degree V-angle ensures smooth,
naturally balanced operation and compact packaging for transverse
mounting. The deep-skirt block structure improves rigidity and reduces
vibration, while the forged crankshaft’s four-bearing support ensures
long-term stability.
A lower main bearing girdle ties all bearing caps together, increasing
structural strength in the lower end. Oil passages and coolant channels
are formed within the block to maintain consistent lubrication and
temperature distribution. Piston cooling jets located beneath the
pistons reduce crown temperature, improving knock resistance and
durability under heavy load.
The cylinder heads are cast aluminum with a SOHC design and four valves
per cylinder. The J30A4 uses Honda’s i-VTEC system on the intake
camshaft, combining variable lift and duration with electronically
controlled cam phasing. This improves airflow, torque, and fuel
efficiency across a wide rpm range.
Valve sizes:
– Intake valves: approx. 35 mm (1.38 inches)
– Exhaust valves: approx. 30 mm (1.18 inches)
Roller rocker arms reduce friction and improve valvetrain efficiency.
The combustion chambers use a pent-roof design that promotes mixture
swirl, efficient flame propagation, and cleaner emissions. A silent-type
timing belt drives the camshafts, and hydraulic lash adjusters eliminate
the need for manual valve clearance adjustments.
The J30A4 uses Honda’s PGM-FI sequential multi-point fuel injection
system. Fuel pressure remains between 350–400 kPa (51–58 psi) via an
in-tank regulator. Multi-hole injectors deliver finely atomized fuel for
consistent combustion.
Fuel system sensors include:
– MAP (Manifold Absolute Pressure)
– IAT (Intake Air Temperature)
– ECT (Engine Coolant Temperature)
– TPS (Throttle Position Sensor within electronic throttle body)
– Wideband upstream O2 sensor
– Downstream O2 sensor
– Knock sensor
– CKP (Crankshaft Position Sensor)
– CMP (Camshaft Position Sensor)
The fuel system is returnless, reducing evaporative emissions.
Recommended fuel: unleaded gasoline with minimum 87 AKI (91 RON).
Premium fuel may offer improved knock resistance under high load.
The engine employs a full-pressure wet-sump lubrication system using a
crankshaft-driven trochoid oil pump. The system ensures reliable
lubrication at all speeds and conditions.
Specifications:
– Oil capacity with filter: approx. 4.5 liters (4.8 US quarts)
– Oil pressure at 3,000 rpm: 350–500 kPa (51–72 psi)
– Idle oil pressure: 70–120 kPa (10–17 psi)
Oil is routed to the crankshaft, connecting rods, camshafts, valvetrain,
and VTEC mechanisms. Piston coolers reduce thermal load, and a full-flow
oil filter removes contaminants. Recommended oil viscosity: SAE 5W-20 or
0W-20. Change interval: 10,000 km (6,000 miles) under normal conditions.
The cooling system is a closed-loop liquid-cooling system using a
belt-driven centrifugal water pump. Coolant circulates through the
block, heads, radiator, and heater core.
Cooling specifications:
– Coolant capacity: approx. 7.0–7.5 liters (7.4–7.9 US quarts)
– Thermostat opening temperature: 78–82°C (172–180°F)
– Fully open temperature: approx. 95°C (203°F)
– System pressure: approx. 90–110 kPa (13–16 psi)
The system includes an aluminum radiator, electric cooling fans, and a
sealed expansion tank. Coolant replacement is recommended every 40,000
km (25,000 miles) or 2 years.
| Intake and Exhaust Systems |
The induction system uses a tuned composite intake manifold designed for
smooth mid-range torque. The throttle body is electronically controlled
(DBW—drive-by-wire). The airbox incorporates a resonator to reduce
intake noise.
Exhaust components:
– Cast stainless exhaust manifolds
– Close-coupled catalytic converter
– Secondary catalytic converter (model dependent)
– Upstream and downstream O2 sensors
The exhaust system is designed to minimize flow restriction while
maintaining emissions compliance and quiet operation.
| Ignition and Electrical System |
The J30A4 uses a coil-on-plug ignition system controlled by the ECU.
Specifications:
– Spark plug gap: approx. 1.0–1.1 mm (0.039–0.043 inches)
– Alternator output: approx. 110–130 amperes
– Starter motor: approx. 1.6–2.0 kW
– System voltage: 12 volts
The ECU manages ignition timing, throttle response, cam phasing
(i-VTEC), emissions, and idle speed. OBD-II diagnostics monitor all
major components.
The J30A4 includes:
– PCV (Positive Crankcase Ventilation)
– EVAP emissions system with charcoal canister
– EGR valve for NOx reduction
– OBD-II monitoring and diagnostics
– Electronic idle-air control
– Length: 670 mm (26.4 inches)
– Width: 690 mm (27.2 inches)
– Height: 720 mm (28.3 inches)
Dry weight ranges from 160–175 kg (353–386 lb), depending on accessory
configuration.
Recommended service intervals:
– Oil and filter: every 10,000 km (6,000 miles)
– Air filter: every 20,000–30,000 km
– Spark plugs: every 100,000 km (62,000 miles)
– Coolant: every 40,000 km or 2 years
– Timing belt: inspect every 100,000 km (60,000 miles)
– Drive belt: inspect every 30,000 km
– Valve clearance: hydraulic—no adjustment required
– Compression: 180–210 psi (1,240–1,450 kPa)
– Cylinder head bolts: 30 Nm (22 lb-ft) + 90° + 90°
– Main bearing caps: 60 Nm (44 lb-ft)
– Connecting rod bolts: 40 Nm (30 lb-ft) + 90°
– Flywheel bolts: 88 Nm (65 lb-ft)
– Crank pulley bolt: 235–245 Nm (173–181 lb-ft)
– Intake manifold bolts: 22 Nm (16 lb-ft)
– Exhaust manifold nuts: 30 Nm (22 lb-ft)
– Spark plugs: 18 Nm (13 lb-ft)
– Oil drain plug: 40 Nm (30 lb-ft)
The Honda J30A4 was used in:
– Honda Accord V6 (2003–2007)
– Acura TSX/CL/TL (select regional variants)
– Swaps into lightweight Honda chassis due to compact size and
reliability
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