Honda K24Z1 Specifications
| Engine Model: Honda K24Z1 |
| 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: 166 Hp (124 kW) at 5800 rpm |
| Fuel System Type: Multi-point electronic fuel injection |
____________________________________________________________________________________
The Honda K24Z1 is a 2.4-liter naturally aspirated
inline-four gasoline engine, representing a significant evolution within Honda’s
renowned K-series family. Introduced as part of the third-generation Honda CR-V
lineup, the K24Z1 marked the transition from the earlier K24A series to the “Z”
generation, which was engineered with a primary focus on packaging efficiency,
emissions reduction, and low-end torque delivery suitable for crossover utility
vehicle applications.
The engine’s most distinctive engineering feature is its cylinder head, which
incorporates an integrated exhaust manifold - a departure from the traditional
separate manifold design of its predecessors. This integration allows the
catalytic converter to mount directly to the cylinder head, accelerating
catalyst light-off for improved cold-start emissions while simplifying engine
bay plumbing.
Combined with the i-VTEC system operating on the intake side and a drive-by-wire
throttle, the K24Z1 prioritizes smooth power delivery, fuel efficiency, and
seamless integration with vehicle stability systems. Its long-stroke
architecture, derived from the K-series philosophy, provides robust low-end
torque suited for the heavier CR-V chassis, making it a durable and reliable
powerplant in its application.
Type: 4-Stroke, Water-Cooled, Inline-4.
Orientation: Transverse, Front-Wheel Drive or All-Wheel Drive.
Displacement: 2,354 cc (143.6 cu.in).
Bore: 87.0 mm (3.43 in).
Stroke: 99.0 mm (3.90 in).
Compression Ratio: 9.7:1.
Firing Order: 1-3-4-2.
Redline: 6,500 rpm.
Maximum Power: 166 hp (124 kW) @ 5,800 rpm.
Maximum Torque: 161 lb-ft (218 Nm) @ 4,200 rpm.
Valvetrain: Double Overhead Camshaft (DOHC), 16-Valve, i-VTEC (Intelligent
Variable Valve Timing and Lift Electronic Control) active on the intake valves
only.
The cylinder block is a high-pressure die-cast aluminum
alloy open-deck design, selected to reduce overall engine mass while maintaining
structural rigidity. Cast-in-place iron cylinder liners provide a durable wear
surface for the pistons and piston rings. The block features a deep-skirt
construction that enhances bottom-end rigidity, minimizing vibration and
contributing to the engine’s overall smoothness.
Within the block, a forged steel crankshaft is supported by five main bearings
with a diameter of 55.0 mm (2.165 in). The crankshaft is fully counterweighted
to balance the forces generated by the long 99.0 mm (3.898 in) stroke. Two
internal balance shafts, driven by a chain from the crankshaft, are housed
within the lower crankcase.
These shafts rotate at twice engine speed to counteract the inherent secondary
imbalance of the inline-four configuration, ensuring refined operation across
the rev range. Connecting rods are forged steel with a center-to-center length
of 152.0 mm (5.984 in). The pistons are cast aluminum alloy with a full-floating
piston pin design, featuring a slightly dished crown to achieve the specified
compression ratio while promoting efficient flame propagation.
The cylinder head is constructed from cast aluminum
alloy and integrates the exhaust manifold directly into the casting. This
integrated design reduces the number of sealing surfaces, shortens the exhaust
path to the catalytic converter, and contributes to faster engine warm-up. The
head uses a cross-flow design with the intake manifold on the front and the
exhaust outlet directed toward the firewall in the transverse-mounted
application.
The valvetrain employs a dual overhead camshaft (DOHC) arrangement operating
four valves per cylinder, totaling sixteen valves. The i-VTEC system on the
intake side utilizes a two-rocker system: at low engine speeds, the system
deactivates one of the two intake valves, creating a high-swirl combustion
condition that improves fuel atomization and combustion stability.
At higher engine speeds, a locking pin couples both rocker arms, allowing both
intake valves to open fully for maximum volumetric efficiency. The exhaust
camshaft operates without variable valve lift but utilizes variable valve
timing. The valves themselves are arranged with an included angle of 25 degrees
between intake and exhaust valves to create a compact combustion chamber.
Valve stems are 5.5 mm (0.217 in) in diameter, and valve seat inserts are
manufactured from a heat-resistant sintered material to withstand the elevated
exhaust temperatures resulting from the integrated manifold design. The
camshafts are driven by a single-stage timing chain that routes from the
crankshaft sprocket up the intake side of the cylinder head, with an automatic
hydraulic tensioner maintaining optimal chain tension throughout the engine’s
service life.
The fuel system is Honda’s Programmed Fuel Injection
(PGM-FI), a multi-point electronic fuel injection system that utilizes
sequential injection. This system delivers fuel through injectors positioned in
the intake ports, precisely timed to each cylinder’s intake stroke. The system
operates at a nominal fuel pressure of 320-370 kPa (46-54 psi) at the fuel rail.
A returnless fuel system design is employed, wherein the fuel pressure regulator
is integrated within the fuel pump module inside the fuel tank. This
configuration reduces fuel heating by eliminating fuel return lines and
minimizes evaporative emissions. The engine control unit (ECU) manages injector
pulse width based on inputs from the mass airflow sensor, manifold absolute
pressure sensor, throttle position sensor, and heated oxygen sensors positioned
before and after the catalytic converter.
The drive-by-wire throttle body, with a bore diameter of 60.0 mm (2.362 in),
replaces the mechanical cable linkage, allowing the ECU to modulate throttle
opening for functions such as traction control, stability assist, and idle air
control without additional actuators.
The lubrication system is a fully pressurized, wet-sump
design. A gear-type oil pump, driven directly from the crankshaft, is housed
within the timing chain cover. The pump draws oil from the aluminum sump through
a screened pickup tube and delivers it through a full-flow oil filter mounted
externally on the engine block.
Oil galleries within the cylinder block and cylinder head supply pressurized oil
to the crankshaft main bearings, connecting rod bearings, camshaft journals, and
the i-VTEC control solenoids. A dedicated oil jet system directs lubrication
toward the undersides of the pistons for cooling and lubrication of the piston
pins. The oil pump is designed to provide increasing flow with engine speed,
with a pressure relief valve set to 490 kPa (71 psi) to prevent
over-pressurization at high revolutions.
The engine features a piston cooling oil jet that operates continuously once oil
pressure reaches the specified threshold. The oil pan, constructed from stamped
steel with a capacity of 4.2 liters (4.4 US qt) including the filter,
incorporates internal baffles to maintain oil pickup during vehicle maneuvers. A
water-cooled oil cooler is integrated into the oil filter base, using engine
coolant to stabilize oil temperature under sustained high-load conditions.
The cooling system operates on a pressurized,
thermosiphon-assisted circulation principle with a centrifugal water pump driven
by the serpentine accessory belt. The pump circulates coolant through the
cylinder block, cylinder head, and the integrated exhaust manifold cooling
passages before routing through the radiator. A wax-type thermostat, with an
opening temperature of 78-82°C (172-180°F), regulates coolant flow to maintain
optimal operating temperature.
Coolant flow is directed through the cylinder block in a reverse-flow pattern
relative to older Honda designs, entering the block first and then flowing
upward into the cylinder head to reduce localized hot spots. The cylinder head’s
integrated exhaust manifold incorporates dedicated coolant passages that
surround the exhaust runners, a critical feature for managing the thermal loads
associated with the cast-in manifold. A 1.1-bar (16.0 psi) radiator cap
establishes the system pressure, raising the boiling point of the coolant. The
system’s total capacity, including the radiator, heater core, and engine
passages, is 6.2 liters (6.6 US qt).
An electric cooling fan, controlled by the ECU via a coolant temperature sensor,
provides forced airflow through the radiator when natural convection is
insufficient. The cooling system also supplies heated coolant to the heater core
for cabin climate control and to the throttle body to prevent icing in cold
climates.
| Intake and Exhaust Systems |
Intake System: The intake system features a molded
plastic intake manifold with long, tuned runners designed to enhance
low-to-midrange torque. A variable-length intake system is not employed;
instead, the manifold geometry is optimized for the engine’s torque peak at
4,200 rpm. An acoustic control induction system (ACIS) valve within the manifold
alters the effective intake tract length to balance volumetric efficiency across
the rev range.
Exhaust System: The exhaust system begins at the integrated manifold within the
cylinder head, where a three-way catalytic converter mounts directly to the
head’s exhaust outlet flange. A single heated oxygen sensor is positioned
upstream of the catalyst, with a secondary sensor downstream for catalyst
efficiency monitoring. The exhaust system continues with a single pipe routing
to a centrally mounted muffler with a single tailpipe outlet.
The ignition system is a fully electronic, coil-on-plug
design. An individual ignition coil is mounted directly over each spark plug,
eliminating high-tension spark plug wires. The ECU controls ignition timing
based on engine speed, load, knock sensor input, and coolant temperature,
advancing timing for efficiency and retarding timing to suppress detonation.
Electrical and Control Systems: The engine is managed
by a 32-bit ECU that governs fuel injection, ignition timing, i-VTEC engagement,
idle speed, and electronic throttle control. The ECU communicates with the
vehicle’s body control module via a controller area network (CAN) bus,
integrating engine management with transmission control, vehicle stability
assist, and cruise control functions. The system utilizes a 12-volt electrical
architecture with a 120-amp alternator.
Emissions Control: Emissions are controlled through a combination of three-way
catalytic conversion, exhaust gas recirculation (EGR), and evaporative emission
control. The EGR system routes a portion of exhaust gas back to the intake
manifold through a valve mounted on the cylinder head, reducing combustion
temperatures and suppressing nitrogen oxide formation. The evaporative system
captures fuel vapors in a charcoal canister and purges them into the intake
manifold during engine operation.
The engine assembly, complete with intake manifold,
exhaust manifold integrated into the head, and all ancillary components,
measures 610 mm (24.0 in) in length, 660 mm (26.0 in) in width, and 690 mm (27.2
in) in height. The engine’s dry weight, without coolant or oil but including the
intake manifold, exhaust manifold integration, and all standard accessories, is
148 kg (326 lb). The cylinder block alone accounts for 32 kg (71 lb) of this
total.
Oil and Filter Change: Engine oil and filter
replacement is required at intervals not exceeding 8,000 km (5,000 mi) under
severe service conditions or 12,000 km (7,500 mi) under normal conditions. The
engine oil capacity with filter replacement is 4.2 liters (4.4 US qt).
Recommended oil viscosity is SAE 5W-20, meeting API service grade SN or higher.
Spark Plugs: Spark plugs are NGK IZFR6K-11S or Denso SKJ20DR-M11S iridium-tipped
units. Replacement interval is 160,000 km (100,000 mi). The spark plug gap is
factory set at 1.0-1.1 mm (0.039-0.043 in) and is not adjustable due to the
fine-wire iridium center electrode.
Valve Clearance: Valve clearance inspection and adjustment are performed with
the engine cold. Intake valve clearance is 0.21-0.25 mm (0.008-0.010 in).
Exhaust valve clearance is 0.25-0.29 mm (0.010-0.011 in). Adjustment is
accomplished via threaded tappet screws with locknuts on the rocker arms.
Timing Chain: The timing chain is designed for the engine’s service life.
Inspection of the automatic hydraulic tensioner extension is recommended at
240,000 km (150,000 mi). Chain replacement is indicated if tensioner piston
extension exceeds 12.0 mm (0.472 in) from the tensioner body.
Drive Belts: The serpentine accessory drive belt should be inspected for
cracking, glazing, or fraying every 24,000 km (15,000 mi) and replaced at
160,000 km (100,000 mi) or as condition dictates.
Coolant: Honda Long-Life Antifreeze/Coolant Type 2, a phosphate-based ethylene
glycol formulation, is specified. Replacement interval is 160,000 km (100,000
mi) for the initial fill and 80,000 km (50,000 mi) thereafter.
Cylinder head bolts are tightened in a multi-stage
sequence to achieve a final torque of 74 Nm (55 lb-ft), followed by an
additional 90-degree turn. Main bearing cap bolts are torqued to 54 Nm (40
lb-ft) plus an additional 90-degree turn. Connecting rod cap nuts are tightened
to 34 Nm (25 lb-ft) plus an additional 90-degree turn.
The camshaft bearing caps require a torque of 26 Nm (19 lb-ft). Intake manifold
mounting nuts are torqued to 24 Nm (18 lb-ft). Exhaust manifold fasteners,
securing the catalytic converter to the integrated head, are torqued to 32 Nm
(24 lb-ft). The spark plugs are installed to 18 Nm (13 lb-ft). Oil pan bolts
receive 12 Nm (9 lb-ft). The crankshaft pulley bolt, a high-torque fastener, is
tightened to 181 Nm (133 lb-ft).
The Honda K24Z1 engine was utilized exclusively in the
third-generation Honda CR-V for the North American market and select global
regions
Specific applications include: 2007-2009 Honda CR-V (RE chassis): LX, EX, and
EX-L trims with front-wheel drive and Real Time all-wheel-drive configurations.
The engine was paired with either a five-speed automatic transmission or, in
certain markets, a six-speed manual transmission. Production of the K24Z1
concluded with the introduction of the fourth-generation CR-V and the transition
to the K24Z series variants with revised emissions equipment.
The engine remains notable for its integration
of compact packaging, thermal efficiency improvements, and durable
construction tailored to the demands of crossover vehicle operation.
____________________________________________________________________________________
| Car Engines Technical Specifications |
| Small Engines Technical Specifications |
| Industrial Engines Technical Specifications |
| Outboard Engines Technical Specifications |
