Honda K24 A, Z, Y, W 2.4 l engine

Honda K24 engine specifications

Honda K24 engine troubleshooting and repair

Engines K24 came to replace the motors F23 and created on the basis of 2-liter K20, by installing a crankshaft with increased piston stroke to 99 mm (was 86 mm), increased the cylinder block in height to 231.5 mm (was 212 mm), increased in diameter and pistons, but only by 1 mm (to 87 mm), and their height remained unchanged – 30 mm. The connecting rods were also installed with a length of 152 mm. Otherwise, the same chain engine, some versions are equipped with balancer shafts, the intake with variable geometry, the cylinder-head is equipped with a system refined I-VTEC, as on the younger motor, there are no hydrocompensators on the K24, adjustment of valves every 40 thousand kilometers (if necessary).

Modifications of the engine Honda K24

• K24A1 – the first civilian version, the motor has a two-stage intake manifold, the i-VTEC system on the intake camshaft is tuned for economy and ecology. Compression ratio is 9.6, power is 160 hp at 6000 rpm, torque is 220 Nm at 3600 rpm. It is found on Honda CR-V.
• K24A2 – motor for larger cars, uses a different crankshaft, reinforced connecting rods, other pistons, compression ratio increased to 10.5, replaced camshafts for more evil, increased throttle, different intake/exhaust. VTEC shifts at 6000 rpm. Power is 200 hp at 6800 rpm, torque 225 Nm at 4500 rpm. In 2006, the engine received an 80 mm diameter intake (was 70 mm), 64 mm throttle plate (was 60 mm), exhaust on 57 mm pipe (was 52 mm). As a result, power has risen to 205 hp at 7000 rpm, torque 231 Nm at 4500 rpm.
• K24A3 – analog of K24A2 for Europe and Australia.
• K24A4 (K24A5, K24A6) – civilian motor with i-VTEC on the intake shaft, which can change the phase by +\- 25 °, compression ratio 9.7, power 160 hp at 5500 rpm, torque 218 Nm at 4500 rpm.
• K24A8 – 166-horsepower version with electronic throttle, i-VTEC starts at 2400 rpm.
• K24Z1 – analog of K24A1, intake manifold is changed, the cylinder from K24A4, compression ratio 9.7, power 166 hp at 5800 rpm, torque 218 Nm at 4200 rpm. The engine was put on Honda SRV.
• K24Z2 – compression ratio increased to 10.5, there are other camshafts, power 177 hp at 6500 rpm, torque 224 Nm at 4300 rpm.
• K24Z3 – compression ratio increased to 11, shafts even more uprated, 190 (201) hp
• K24Z4 – analog of K24Z1.
• K24Z5 – analog of K24Z2, power of 181 horses.
• K24Z6 – analog of K24Z5, other camshafts installed, 180 horsepower.
• K24Z7 – motor for Civic Si and Acura ILX. It has changed pistons, connecting rods, intake manifold, camshafts, VTEC switches at 5000 rpm. Power is 205 hp at 7000 rpm, 230 Nm of torque at 4400 rpm
• K24Y1 – Honda SRV engine for the Thai market, compression ratio 10.5, power 170 hp at 6000 rpm, torque 220 Nm at 4300 rpm.
• K24Y2 – Honda Crosstour motor, lower compression ratio – 10, the camshafts are angrier, power 192 hp at 7000 rpm, torque 220 Nm at 4400 rpm.
• K24W1 – engine for Accord, is a part of Earth Dreams series (index W) with direct injection. Relative to the K24Y, the intake/exhaust has been changed, now the intake is at the rear, the exhaust is at the front, compression ratio is 11.1, camshafts are quiet, VTEC switches at 4800 rpm. Engine output is 185 hp at 6400 rpm, 245 Nm of torque at 3900 rpm
• K24W2 – analog of K24W1 with other camshafts, power of 188 hp
• K24W3 – analog of K24W2 with slightly modified exhaust, 190 hp
• K24W4 – modified injection system, compression ratio 10.1, lower camshafts, power 174 hp at 6200 rpm, torque 225 Nm at 4000 rpm

Problems and reliability of Honda K-series engines

Honda’s K-series engine family was introduced in 2001. These gasoline 4-cylinder engines have been used in literally every major Honda and co-platform Acura model. K-series engines exist in 2.0 and 2.4 liter displacement versions, and there is also a 2.3 liter turbocharged version. These engines have replaced several older lines of Honda gasoline powertrains.

K-series engines have said goodbye to some traditional solutions. In particular, the crankshaft here rotates in the right direction (i.e. clockwise), whereas before all Honda engines were “left-hand drive”. The timing system uses a chain instead of a belt. All motors use the i-VTEC system, which is implemented either on both camshafts or only on the intake camshaft.

All K-series engines are unified among themselves. They are like a constructor – depending on the applied parts and components, the engine can develop from 150 to 220 hp. Or even up to 300 with serious tuning.

How reliable are Honda K-series engines?

Engines Honda K-series were received by fans of the brand very warmly, as they pleased with the balance of power, traction and economy. With reliability was also in full order, but only for the first time. Then these Japanese power units gave unpleasant surprises, many of which are associated with “amateurism” in terms of selection and replacement of engine oil. Now about everything in order.

Throttle valve and uneven idle

Depending on the model and year of manufacture, the K20A engine is equipped with an electronic or mechanical throttle. The mechanical choke is equipped with an idle control valve actuated by an electric servo. These assemblies create problems when dirty. They need to be removed and cleaned, and after installation, they must be adapted.

In the damper can fail its position sensor, which is specifically indicated by the corresponding fault code (P0122) and highly floating engine speeds.

Fast idle thermal valve

For fast warm-up at high idle speeds, Honda engines, not only K-series engines, use air supply directly to the fuel injector nozzles. For the air supply is responsible for a special thermo valve, which goes together with the flange of the cooling system. When the antifreeze warms up to 60°, the valve closes the supply of additional air to the injectors.

This valve often fails and is the cause of the engine stalling a few seconds after starting or constantly high idle speeds.

You can simply get rid of this valve, but then the engine will not hold high rpm for warm up.

Intake manifold length change valve

The manifold of the two-liter Honda CR-V motor is equipped with a mechanism to change its length. Switching between long and short channels is the responsibility of a rotating valve-drum driven by a vacuum actuator. Switching to short channels takes place when 4700 rpm is reached. This mechanism is controlled by an electro-vacuum valve and monitored by a drum position sensor.

There are problems with this mechanism: usually vacuum is lost or the drum jams if the owner neglected the quality and timing of air filter replacement. Errors P1078 and P1077 are registered. Usually, to solve the problem with the valve in the intake manifold, it is enough to remove it, wash it well together with the intake manifold.

VTEC valve

The valve that controls the VTEC system mainly suffers due to oil economy. A clear sign of its failure is when the motor does not develop more than 3500 rpm and error P1259 or P2646 is registered. But usually the valve is not broken, but clogged metal mesh-filter, which is soldered into the rubber gasket between the valve and the cylinder-head.

This gasket and another one in the VTEC valve is the first to attract attention – it gets stuffy and starts leaking oil. Have to replace both gaskets.

VTC solenoid

The phase shifter on the intake camshaft is controlled by a solenoid of standard design. However, there is a filter screen in the channel that feeds oil to it. The mesh and rubber gasket are mounted under a separate cover. The mesh is the first to take the impact, sifting out all impurities from the oil. If there are problems with the phase shifter, the “check engine” lights up and errors P1009 and P2646 are recorded.

On 2-liter engines of Honda K-series the VTC clutch is not bad, but on 2.4-liter engines it started to crack by the mileage of 100 000 km or even earlier – before the end of the warranty period. There was a recall campaign on the clutches of 2.4-liter engines. But “kind of improved” clutches started to crack after 1-2 years.

VTC clutches also fail on 2-liter engines. The symptom is the same: crackling at cold start and error P0341.

The timing chain

Stretching of the timing chain on Honda K20 engines is not uncommon, and it usually happens at mileage over 200,000 km. However, to serious problems associated with its jumping, usually does not come to serious problems. Usually, the same error P0341, indicating problems with phase distribution, informs that it is time to change the chain. A stretched chain on a Honda engine usually does not make noise. Specifically identify the stretching of the chain can be identified by a strongly extended hydraulic tensioner rod: on the engine K20A should not come out more than 16 mm.

However, the rod can be inspected only after removing the timing cover. There is a hatch opposite the hydraulic tensioner, but through it you can only loosen the tension of the chain when working on the removal of camshafts.
Therefore, to assess the condition of the chain, you can combine and check the marks on the camshaft stars and crankshaft pulley. The greater the lag of the marks, the more the chain is stretched. If the marks do not match by 1 cm or more, it is better to change the chain.

Wear of camshaft cams

As operation showed, after 4-5 years after their appearance by the mileage of 80 000 – 100 000 km, very many engines K-series were sent to repair. In particular, the cams of the exhaust camshaft wore out badly on the unboosted engines – they wore so much that the valves practically did not open. As a result, the engine would start to tingle, its power would drop, and consumption would increase significantly. In order to repair it was necessary to change the worn camshaft. And the new exhaust camshaft was shrunk again, literally within 30 000 km.

It is still not clear why the cams wore out. There are several versions of the story.

1. One version of the wear was due to using the wrong oil or not following the change intervals. Critical wear of cams occurred when using too viscous oil such as 0W-40 to 5W-50, which the owners poured on their own initiative. Also the trouble did not pass those who used branded oil of viscosity 0W-20, but changed it not in time. In general, K24A motors should be filled with oil viscosity 0W-20 or 5W-20 and change it every 7500 km or even earlier. With such an interval it is changed even in Japan.
2. The second version, a strong and uneven wear of cams of exhaust camshafts is due to the fact that the valve clearance was not adjusted in time. On motors without i-VTEC system, one cam presses two valves at once on the exhaust camshafts. And if these valves begin to “dance” clearances, leading to misalignment, the cam experiences shock loads. First, the “cemented” surface layer of metal on the cam is painted out, then the soft metal of the cam itself is quickly worn away. As a result, the cam profile is rounded, turning into an oval or a circle – depending on how long the owner has been away from the problem.

Check the thermal clearances of the valves should be checked at least once every 40,000 km. Adjustment takes about half an hour, you need a dipstick to measure the gaps, a screwdriver and a wrench for 10.

Inserts

It is not uncommon for K20A engines to rotate the liners, usually connecting rod, less often the main liners. The cause may be unsuccessful selection of oil or changing it at long intervals. If you do this and constantly burn off, you can almost certainly get to the overhaul or replacement of the engine.