Honda K24A6 Specifications
| Engine Model: Honda K24A6 |
| Engine Type: 4-cycle inline 4-cylinder DOHC 16-valve i-VTEC liquid-cooled gasoline |
| Total Displacement: 143.6 cu.in (2.35 L) |
| Rated Engine Power: 160 Hp (119 kW) at 5500 rpm |
| Fuel System Type: Multi-point electronic fuel injection |
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The Honda K24A6 represents a refinement within the
K-series family, positioned as an economy-oriented 2.4-liter naturally aspirated
inline-four. Developed as an evolution of the K24A4, its engineering focus
prioritizes fuel efficiency, emissions compliance, and mid-range tractability
for passenger car applications. The engine utilizes a distinctive implementation
of i-VTEC, engaging on the intake side only to promote intake swirl at lower
engine speeds for enhanced combustion stability.
Internal balance shafts mitigate the inherent secondary vibrations of a
large-displacement four-cylinder configuration, contributing to the smooth power
delivery expected in family sedans and minivans. Transition to a drive-by-wire
throttle system in this iteration improved integration with electronic stability
control and enabled more precise fuel management strategies.
The combination of an aluminum block with cast-iron cylinder liners, a
maintenance-free timing chain, and a robust bottom end establishes a foundation
of durability consistent with the manufacturer’s reputation for longevity.
Configuration: Inline four-cylinder, transversely mounted
Valvetrain: Double overhead camshaft (DOHC), 16 valves, i-VTEC system
Displacement: 2,354 cc (143.6 cu.in)
Bore: 87.0 mm (3.43 in)
Stroke: 99.0 mm (3.90 in)
Bore-to-stroke ratio: Undersquare design favoring low-end torque
Compression ratio: 9.7:1
Firing order: 1-3-4-2
Engine rotation: Clockwise (viewed from the crankshaft pulley end)
Maximum power output: 160 hp (119 kW) at 5,500 rpm
Maximum torque: 161 lb-ft (218 Nm) at 4,500 rpm
Engine redline: 6,500 rpm
Fuel cutoff: 6,800 rpm
VTEC engagement point: 2,300 rpm
i-VTEC operation: The system utilizes a two-stage intake rocker arm design.
Below the engagement threshold, one intake valve opens to a reduced lift,
generating a swirl motion within the combustion chamber to improve fuel
atomization and mixture homogeneity. Above 2,300 rpm, the system switches to a
conventional high-lift profile where both intake valves open fully to enhance
volumetric efficiency.
The cylinder block is constructed from aluminum alloy
with high-pressure die-casting techniques to reduce mass while maintaining
structural rigidity. Cast-iron cylinder liners are integrally cast into the
block during production, providing a durable wear surface compatible with
conventional piston ring materials. The open-deck design, where the cylinder
bores are unsupported at the upper portion of the block, facilitates cooling
efficiency around the combustion chambers but imposes specific requirements for
head gasket sealing under high-load conditions.
The block incorporates a deep-skirt architecture extending below the crankshaft
centerline, enhancing overall rigidity and reducing vibration transmission.
Internal webbing reinforcements are cast around the main bearing bulkheads to
manage loads generated by the long-stroke crankshaft. A separate aluminum oil
pan housing the balance shaft assembly attaches to the lower block structure.
The cylinder head is a sand-cast aluminum component
featuring a cross-flow design with intake ports on the rear and exhaust ports on
the front for transverse mounting configurations. Combustion chambers utilize a
pent-roof configuration with four valves per cylinder arranged at a narrow
included angle to optimize flame propagation.
The i-VTEC system incorporates variable valve timing on the intake camshaft with
a hydraulically actuated cam phaser capable of advancing or retarding intake
valve timing continuously across the operating range. Valve actuation employs a
roller rocker arm system with a three-piece design on the intake side to
facilitate the two-stage lift profile.
Valve seat inserts are manufactured from sintered metal alloys, with intake
seats utilizing a wear-resistant iron-based material and exhaust seats employing
a higher-temperature alloy for durability under thermal stress. Valve guides are
integrated into the cylinder head casting with subsequent machining to precise
clearance specifications. The camshafts are supported by four bearing caps
machined directly into the cylinder head casting for consistent alignment.
Valves: 16 (4 per cylinder)
Intake valve diameter: 34.0 mm (1.34 in)
Exhaust valve diameter: 29.0 mm (1.14 in)
Valve stem diameter: 5.5 mm (0.22 in)
Camshaft drive: Silent-type chain with automatic hydraulic tensioner
The fuel system employs a returnless multi-point
electronic fuel injection architecture. Fuel pressure is regulated by a
pulse-width-modulated fuel pump module within the fuel tank, eliminating the
return line to reduce evaporative emissions. Injectors are top-feed,
high-impedance units with a 12-hole nozzle design to improve fuel atomization.
The engine management system utilizes sequential fuel injection firing
coordinated with camshaft position input to deliver fuel precisely before each
intake event.
Injector flow rate: 235 cc/min at 3.5 bar (51 psi) nominal system pressure.
Fuel requirement: Unleaded regular gasoline with a minimum octane rating of 87
AKI (91 RON).
Fuel rail construction: Stainless steel with integrated pressure damper.
Throttle body: Electronic drive-by-wire, 60 mm (2.36 in) bore diameter with
integrated position sensors.
The lubrication system is a fully pressurized, wet-sump
configuration utilizing a gear-type oil pump driven directly by the crankshaft.
The pump is mounted within the timing chain cover and delivers oil through a
full-flow filter housing before distribution to the main gallery.
Piston cooling jets are integrated into the cylinder block, directing oil
streams to the underside of each piston crown to manage thermal loads under
sustained operation. Counter-rotating balance shafts mounted within the oil pan
are driven by a separate chain from the crankshaft and receive pressurized
lubrication through dedicated passages.
Oil pump type: Rotor-type with crescent.
Oil pressure regulation: Spring-loaded relief valve set at 4.5 bar (65 psi).
Oil capacity with filter change: 4.2 liters (4.4 US qt).
Oil viscosity specification: 5W-20 meeting API service grade SL or higher.
Oil pan construction: Stamped steel with integrated windage tray and balance
shaft housing.
Oil filter: Spin-on canister type, 70 mm hex head, M20 x 1.5 thread.
Cooling system circulation is managed by a belt-driven
centrifugal water pump mounted on the cylinder block. The thermostat is
integrated into the water pump housing, utilizing a wax-pellet element
controlling flow to the radiator.
Coolant flow follows a reverse-flow path, entering the cylinder block first
before circulating upward through the cylinder head to optimize thermal
management of the combustion chambers and exhaust valve areas.
Coolant capacity: 6.2 liters (6.5 US qt) including heater core.
Thermostat opening temperature: 78°C (172°F).
Water pump drive: Serpentine accessory belt.
Radiator fan control: Dual electric fans with PWM control via engine control
module.
Coolant specification: Phosphate-free, silicate-free ethylene glycol blend with
corrosion inhibitors.
| Intake and Exhaust Systems |
Intake System: A composite plastic intake manifold with
variable-length runners improves torque distribution across the engine speed
range. The manifold incorporates a resonance chamber and acoustic tuning to
reduce induction noise while maintaining flow efficiency. An electronically
controlled intake air control valve modulates runner effective length based on
engine load.
Exhaust System: Cast iron exhaust manifold with integrated catalytic converter
positioned close to the cylinder head to accelerate light-off for emissions
compliance. A single oxygen sensor is mounted upstream of the catalyst with a
secondary sensor downstream for catalyst efficiency monitoring.
The ignition system utilizes a coil-on-plug
configuration with individual ignition coils mounted directly over each spark
plug. The engine control module controls dwell time and spark timing based on
load, engine speed, and knock sensor feedback. Knock control employs a
piezoelectric sensor mounted to the cylinder block capable of detecting
detonation events on a per-cylinder basis.
Spark plug type: NGK IZFR6K-11 (iridium center electrode).
Spark plug gap: 1.1 mm (0.043 in) preset, non-adjustable.
Ignition timing: Controlled by ECM, base timing not user-adjustable.
Emissions Control: The engine utilizes a three-way
catalytic converter with closed-loop fuel control. Evaporative emissions are
managed through a sealed fuel system with a charcoal canister and purge solenoid
valve. Positive crankcase ventilation is integrated into the valve cover with an
internal oil separator.
Length: 610 mm (24.0 in)
Width: 640 mm (25.2 in)
Height: 700 mm (27.6 in)
Engine dry weight (complete assembly without fluids): 125 kg (276 lb)
Valve clearance inspection and adjustment interval:
160,000 km (100,000 miles) or if excessive valvetrain noise is detected. Valve
clearance (cold engine): Intake: 0.21-0.25 mm (0.008-0.010 in), Exhaust:
0.25-0.29 mm (0.010-0.011 in).
Timing chain inspection interval: Inspect at 160,000 km (100,000 miles) for
elongation; replacement as required based on tensioner extension measurement.
Spark plug replacement interval: 160,000 km (100,000 miles) for iridium type.
Engine oil change interval: 8,000 km (5,000 miles) under normal conditions;
5,000 km (3,000 miles) under severe service.
Coolant replacement interval: 160,000 km (100,000 miles) or 10 years, then every
80,000 km (50,000 miles) or 5 years. Air filter replacement interval: 48,000 km
(30,000 miles) under normal conditions; inspect more frequently in dusty
environments. Accessory belt replacement interval: Inspect at 80,000 km (50,000
miles); replace if cracking, glazing, or fraying is evident.
Cylinder head bolts (8 mm
x 1.25 thread):
Step 1: 29 Nm (22 lb-ft)
Step 2: 90-degree rotation
Step 3: Additional 90-degree rotation
Main bearing cap bolts:
Step 1: 29 Nm (22 lb-ft)
Step 2: 90-degree rotation
Step 3: Additional 90-degree rotation
Connecting rod cap bolts:
Step 1: 20 Nm (15 lb-ft)
Step 2: 90-degree rotation
Camshaft bearing cap bolts: 26 Nm (19 lb-ft)
Crankshaft pulley bolt: 181 Nm (133 lb-ft)
Flywheel/flexplate bolts: 98 Nm (72 lb-ft)
Intake manifold bolts: 22 Nm (16 lb-ft)
Exhaust manifold nuts: 34 Nm (25 lb-ft)
Spark plugs: 18 Nm (13 lb-ft)
Valve cover bolts: 12 Nm (9 lb-ft)
Oil pan bolts: 12 Nm (9 lb-ft)
Water pump bolts: 12 Nm (9 lb-ft)
Timing chain tensioner bolts: 25 Nm (18 lb-ft)
Drive-by-wire throttle body bolts: 12 Nm (9 lb-ft)
Engine mount through-bolts: 64 Nm (47 lb-ft)
The Honda K24A6 engine was
primarily distributed in the North American market during the mid-2000s
production period:
2006-2007 Honda Accord LX sedan and coupe.
2006-2007 Honda Accord EX sedan and coupe.
Additional applications in select international
markets:
2003-2006 Honda Odyssey (Asian and Australian market variants).
2005-2007 Honda CR-V (certain Southeast Asian market configurations).
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