Honda K24Z6 Specifications
| Engine Model: Honda K24Z6 |
| 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: 180 Hp (134 kW) at 6800 rpm |
| Fuel System Type: Multi-point electronic fuel injection |
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The Honda K24Z6 is a 2.4-liter naturally aspirated
inline-four engine, representing the final evolution of the K-series powerplant
for the third-generation Honda CR-V. Developed as a refinement of the K24Z1, its
primary design goals centered on reducing internal friction, enhancing thermal
efficiency, and delivering a responsive powerband suitable for a compact sport
utility vehicle.
The K24Z6 is distinguished by its use of the “Z” series cylinder head casting,
which integrates the exhaust manifold directly into the head - a design choice
that accelerates catalytic converter light-off for reduced emissions and
simplifies the engine’s thermal management.
This engine continues Honda’s hallmark i-VTEC (intelligent Variable Valve Timing
and Lift Electronic Control) architecture, but with a unique application focused
on efficiency. Unlike performance-oriented VTEC systems that switch between
high-lift cam profiles, the K24Z6’s system operates on the intake valves and is
calibrated to switch from a 12-valve mode (deactivating one intake valve per
cylinder) to a full 16-valve mode at low engine speeds, optimizing swirl and
combustion stability.
This approach, combined with a raised compression ratio and reduced mechanical
losses, yields a balance of smooth power delivery, strong mid-range torque, and
improved fuel economy.
The K24Z6 is a water-cooled, four-stroke, inline-four-cylinder engine. Its
cylinder arrangement is transverse, optimized for front-wheel-drive and
all-wheel-drive vehicle platforms. The engine block and cylinder head are
constructed from aluminum alloy to minimize overall mass.
The valvetrain is a dual overhead camshaft (DOHC) design, actuating sixteen
valves. The i-VTEC system operates on the intake camshaft only, utilizing a
three-rocker-arm system per cylinder. The exhaust camshaft is equipped with VTC
(Variable Timing Control), allowing continuous adjustment of camshaft phasing
across a range of up to 50 degrees. This combination allows for precise control
over valve overlap, contributing to both fuel efficiency and power output.
Displacement is precisely 2,354 cc (143.6 cu.in), achieved through a bore of
87.0 mm (3.43 in) and a long-stroke crankshaft design with a stroke of 99.0 mm
(3.90 in). The long-stroke configuration favors torque production, a critical
attribute for the engine’s application in a sport utility vehicle. The
compression ratio is set at 10.5:1, an increase over earlier K24 variants. This
higher compression ratio improves thermodynamic efficiency, extracting more
energy from the air-fuel mixture.
Power output is rated at a maximum of 180 horsepower (134 kW) achieved at 6,800
rpm. Peak torque is 161 lb-ft (218 Nm) and is delivered at 4,400 rpm. The engine
redline is established at 7,100 rpm, after which the fuel cut-off engages. The
i-VTEC engagement point is a distinct feature, occurring at 2,300 rpm. At this
threshold, the system transitions from operating with one intake valve
deactivated per cylinder to a standard 16-valve configuration, providing a
seamless shift in torque characteristics.
The cylinder block is an open-deck, high-pressure
die-cast aluminum component. This construction reduces weight while maintaining
sufficient structural rigidity for the engine’s operational demands. Cast-iron
cylinder liners are employed to provide a durable, low-friction surface for the
pistons. The block is designed with a deep-skirt configuration, extending the
side walls below the crankshaft centerline, which contributes to overall engine
rigidity and reduced noise, vibration, and harshness.
The crankshaft is forged from steel and features eight counterweights to balance
the reciprocating mass of the long-stroke design. It is supported by five main
bearings. Connecting rods are constructed from forged steel and feature a
fracture-split design at the big end, ensuring precise cap alignment and
increased strength.
Pistons are made from a high-silicon aluminum alloy. Friction reduction is a key
engineering focus; the piston skirts receive a specialized molybdenum disulfide
coating, and the piston rings are ion-plated to minimize drag against the
cylinder walls.
The cylinder head is a cross-flow, aluminum alloy
casting with a pent-roof combustion chamber design. Its most prominent feature
is the integrated exhaust manifold. The exhaust ports converge within the head
casting to form a single outlet flange, eliminating a traditional separate
exhaust manifold. This integration allows the catalytic converter to be
positioned in close proximity to the exhaust ports, drastically reducing the
time required to reach operating temperature after a cold start.
The valves are arranged with a narrow included angle to promote a compact
combustion chamber. Intake valves have a diameter of 35.0 mm (1.38 in), while
exhaust valves are 30.0 mm (1.18 in) in diameter. The i-VTEC system on the
intake side utilizes a primary, secondary, and mid rocker arm for each cylinder.
The VTC actuator on the exhaust camshaft is hydraulically actuated and
controlled by the Engine Control Unit (ECU), enabling precise valve timing
adjustment based on engine load and speed. Valve clearance is achieved through a
shim-under-bucket design, requiring manual adjustment to maintain optimal
performance and prevent valve damage.
The fuel system is a Programmed Fuel Injection (PGM-FI)
system, employing multi-point port injection. This system utilizes one fuel
injector per cylinder, positioned in the intake manifold runner, spraying fuel
directly toward the back of the intake valves. This port injection strategy
promotes fuel atomization and valve cooling.
Fuel delivery is managed by an electric fuel pump mounted within the fuel tank,
supplying fuel at a regulated pressure of approximately 50 psi (345 kPa) to the
injectors. The ECU controls injector pulse width and timing based on inputs from
the mass airflow sensor, throttle position sensor, and oxygen sensors to
maintain a precise air-fuel ratio for optimal combustion, emissions control, and
drivability.
The lubrication system is a fully pressurized, wet-sump
design. A gear-type oil pump, driven directly by the crankshaft, is mounted
within the oil pan. This pump generates oil pressure to supply all critical
engine components, including the crankshaft main bearings, connecting rod
bearings, camshaft journals, and the i-VTEC and VTC actuation mechanisms.
The system includes a full-flow oil filter mounted externally on the cylinder
block for ease of service. A water-cooled oil cooler is integrated into the oil
filter base, helping to maintain stable oil temperature under high-load
conditions. The recommended oil viscosity is 0W-20 or 5W-20, with synthetic oil
strongly advised to ensure proper lubrication of the i-VTEC mechanisms and to
maximize service life.
The cooling system is a thermostatically controlled,
pressurized liquid cooling system. A belt-driven centrifugal water pump
circulates coolant through the cylinder block, cylinder head, and the heater
core. The integrated exhaust manifold within the cylinder head is cooled by the
same coolant passages, which aids in reducing exhaust gas temperatures and
contributes to faster engine warm-up.
A wax-type thermostat, with an opening temperature of 176°F (80°C), regulates
coolant flow between the engine and the radiator. The system includes an
electric cooling fan, controlled by the ECU based on coolant temperature sensor
input, to maintain consistent operating temperatures during idle and low-speed
operation.
The ignition system is a distributorless, coil-on-plug
design. Each cylinder has its own ignition coil mounted directly over the spark
plug, eliminating high-tension spark plug wires. This system allows for precise
ignition timing control by the ECU, optimizing combustion for power, fuel
economy, and emissions. Iridium-tipped spark plugs are specified for their
durability and consistent firing characteristics.
0Intake System: The engine utilizes a drive-by-wire
(DBW) electronic throttle body. This system replaces a mechanical cable with
electronic sensors and an actuator, allowing the ECU to manage throttle opening
for functions such as cruise control, traction control, and idle stabilization.
The intake manifold is constructed from composite plastic to reduce weight and
features variable-length intake runners to optimize airflow across the engine’s
operating range.
Emission Control: Emissions are managed through a three-way catalytic converter,
a closed-loop fuel control system utilizing heated oxygen sensors before and
after the catalyst, and a positive crankcase ventilation (PCV) system. The
integrated exhaust manifold contributes significantly to the rapid activation of
the catalytic converter, reducing cold-start hydrocarbon emissions.
Length from the drive pulley to the transmission
mounting face is 23.0 in (584 mm). Width, measured across the valve cover and
intake manifold, is 26.4 in (670 mm). Height from the top of the valve cover to
the bottom of the oil pan is 27.2 in (690 mm). The dry weight of the complete
engine assembly, without the transmission or accessory components like the
alternator and power steering pump, is 320 lb (145 kg).
Routine maintenance is critical for the longevity of
the interference-type K24Z6. The timing chain is of a silent-type design with a
friction-reducing coating and is intended to last the engine’s life, provided
the engine oil is maintained at proper levels and intervals. The timing chain
tensioner is hydraulic and should be inspected for leaks during service. Oil
Capacity: With oil filter change, the capacity is 4.4 US qt (4.2 L). Without
filter change, capacity is 4.0 US qt (3.8 L).
Spark Plugs: The specified spark plug is NGK ILZKR7B-11S or equivalent iridium
type. The spark plug gap is 0.043 in (1.1 mm). Replacement interval is 100,000
miles (160,000 km). Valve Clearance (Cold): Adjustment is required at the
recommended service intervals. Intake valve clearance is 0.008-0.010 in
(0.21-0.25 mm). Exhaust valve clearance is 0.010-0.011 in (0.25-0.29 mm).
Engine Coolant: The system uses Honda Long Life Antifreeze/Coolant Type 2. Total
cooling system capacity is 6.1 US qt (5.8 L). Drive Belts: The serpentine
accessory drive belt should be inspected for cracks or fraying. Tension is
maintained by an automatic tensioner. Oil Change Interval: Under normal driving
conditions, the engine oil and filter should be changed every 7,500 miles
(12,000 km) or every 12 months, whichever comes first. Severe service conditions
require more frequent intervals.
Cylinder Head Bolts: Stage one: 22 lb-ft (30 Nm). Stage
two: 90-deg turn.
Main Bearing Cap Bolts: 40 lb-ft (54 Nm) plus a 90-deg turn.
Connecting Rod Cap Bolts: 24 lb-ft (33 Nm) plus a 90-deg turn.
Camshaft Bearing Cap Bolts: 12 lb-ft (16 Nm) for the 8 mm bolts.
Camshaft Bearing Cap Bolts: 21 lb-ft (28 Nm) for the 10 mm bolts.
Intake Manifold Mounting Nuts: 16 lb-ft (22 Nm).
Exhaust Manifold Flange Nuts: 30 lb-ft (40 Nm).
Spark Plugs: 13 lb-ft (18 Nm).
Valve Cover Bolts: 9 lb-ft (12 Nm).
Oil Filter: 16 lb-ft (22 Nm) or 7/8 turn after gasket contact.
Crankshaft Pulley Bolt: 130 lb-ft (176 Nm).
The Honda K24Z6 engine was utilized as the exclusive
powertrain for the facelifted third-generation Honda CR-V. Its production run
spanned the 2010 and 2011 model years. This engine was fitted to both
front-wheel-drive and all-wheel-drive configurations of the CR-V for the North
American market.
It was also utilized in certain European and
Asian market CR-V models produced during the same period, where it
served as the top-tier naturally aspirated gasoline engine option before
the introduction of the fourth-generation model with the newer Earth
Dreams technology powertrains.
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