Honda K20A (Z) 2.0 engine

Honda K20A engine characteristics

Honda K20 engine troubleshooting and repair

Honda K-series engines were received by fans of the brand very warmly, as they pleased with the balance of power, traction and economy. Reliability was also in good order, but only at first. 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 valve. The mechanical throttle 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 the sensor of its position, which is specifically indicated by the corresponding fault code (P0122) and strongly floating engine speeds.

You can choose and buy a throttle valve Honda on the website of the company “AutoStrong-M”.

Fast idle thermal valve

For fast warm-up at high idle speeds on Honda engines, not only K-series, air supply directly to the nozzles of fuel injectors is used. A special thermo valve is responsible for the air supply, which is assembled 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 for changing 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 from 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. Both gaskets have to be replaced.

VTC solenoid

The phase shifter on the intake camshaft is controlled by a solenoid of standard design. However, a filter mesh is installed in the channel that supplies 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 rare, and it usually happens when the mileage exceeds 200 000 km. However, it usually does not come to serious problems connected with its jumping. 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 to the mileage of 80 000 – 100 000 km, very many engines of K-series were sent for repair. In particular, the cams of the exhaust camshaft on unboosted engines were badly worn – they were so worn 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 version. According to one version, the wear was caused by 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.

According to the second version, strong and uneven wear of cams of exhaust camshafts is due to the fact that the valve clearances were not adjusted in time. On motors without i-VTEC system, one cam presses on two valves at once on the exhaust camshaft. 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 rounds off, becomes an oval or a circle – depending on how long the owner has been away from the problem.

Honda K20 engine modifications

1. K20A – produced since 2001 sports engine, the engine output of 215 hp at 8000 rpm, installed camshafts with parameters of intake 244 (8.84)/280 (12.65)/245 (9.68), exhaust 240 (8.59)/278 (12.14)/244 (8.74), double valve springs, compression ratio of 11.5. This engine uses balancer shafts. In 2007, the K20A engine was modernized, the intake manifold was changed, the throttle plate was increased to 64 mm (it was 62 mm), the cylinder head was improved (intake, exhaust), reinforced connecting rods were installed, the compression ratio increased to 11.7, the inclusion of VTEC system was moved 200 revolutions down and it now starts working at 5800 rpm. The 4-2-1 exhaust manifold and the exhaust in general were changed and finalized, the pipe diameter remained the same (54 mm). What did all this do? Power of the modernized engine has increased to 220 hp at 8000 rpm, torque has increased from 206 Nm at 7000 rpm to 215 Nm at 6100 rpm. The cut-off has been moved to 8600 rpm. This engine was put on the Japanese Civic Type R FD2.
2. K20A1 – civilian version of K20A, replaced piston under low compression ratio of 9.8, installed quiet camshafts, intake/exhaust channels of smaller diameter, 155 hp. The motor is found on the Honda Stream.
3. K20A2 is a sporty 201-horsepower motor, with another short intake manifold, oil injectors, another crankshaft, other connecting rods and pistons are present. Also, there are evil camshafts with intake 238 (7.36)/278 (12.42)/240 (7.82), exhaust 240 (7.14)/280 (11.12)/242 (7.72). The engine revs up to 7900 rpm. Compression ratio is increased to 11, iVTEC is engaged at 5800 rpm. (6000 rpm for Civic Type-R).
4. K20A3 – Civic motor with i-VTEC system for adjusting the intake shaft timing. VTEC shifting is set to 2200 rpm. There is a two-stage manifold on the intake, which shifts at 4600 rpm. The compression ratio is 9.8 and 160 horsepower. Found on the RSX and Civic.
5. K20A4/K20A5/K20A6 – the same civilian motor, compression ratio 9.8, power 150/152/155 hp. Differences in VTEC.
6. K20Z1 – sporty high-revving engine for Type-S versions, modified K20A2, changed intake/exhaust, shafts are a little bit angrier, i-VTEC is included after 5800 rpm. Power is 210 hp at 7800 rpm, torque 194 Nm at 6200 rpm.
7. K20Z2 – simple motor, compression ratio 9.8, power 155 hp at 6000 rpm, torque 188 Nm at 4500 rpm.
8. K20Z3 is a sporty version with full i-VTEC, which shifts at 5800 rpm. Also used electronic throttle, modified camshafts, modified intake/exhaust, compression ratio 11, power 197 hp at 7800 rpm, torque 188 Nm at 6200 rpm. The engine was put on the Honda Civic Si.
9. K20Z4 – similar to K20Z3 modification, different camshafts, iVTEC is switched on 400 rpm earlier, at 5400 rpm. Power is 201 hp at 7800 rpm, torque is 193 Nm at 6800 rpm. Found on the European Honda Civic Type R.
10. K20C1 is a turbocharged engine for the Civic Type R. The engine is equipped with direct fuel injection, VTEC system on the intake and exhaust shafts, is characterized by refined intake ducts and turbine, which blows 1.4 bar. It also features 9.8 compression ratio pistons, forged connecting rods and a lightweight crankshaft. Power output of the Type R motor is 310 hp at 6,500 rpm and 400 Nm of torque at 2,500-4,500 rpm. The cutoff is set at 7000 rpm.
11. K20C2 is the atmospheric motor for the regular Civic. It uses direct fuel injection with i-VTEC system on both camshafts. The engine has a lightweight crankshaft, new pistons for compression ratio of 10.8, modified cylinder head, with other combustion chambers. Power of this engine is 158 hp at 6500 rpm, torque 187 Nm at 4200 rpm.

Honda K20 engine tuning

Atmospheric. Hybrid

There is no sense to tuning usual non-inflating motors, in any case you need to change the head on Type R, the CMP from the same, intake/exhaust, brain, and even better to buy a contract engine Honda K20A and not to make a garden. Ready K20A you can pump up a little, put a choke from FD2, replace the receiver on something like Toda (or other), exhaust 4-2-1 Toda (or other), catback, ECU Hondata K-Pro, this junk will allow you to raise the power to 230 hp, complementing it with sports camshafts Skunk2 (or other) level Stage 2, Skunk2 plates, reinforced springs, injectors 400 cc, you can bring the output to 250 hp. On even meaner shafts, with porting, we’ll take a little more off, but the revs will be well over 9000 rpm.

To get even more power in the atmospheric version, you need to either make a hybrid K20/K24 or swap the engine K24A2 and tuning it in the same way. The motor is assembled on the basis of K24 block, the head is put from K20A or K20A2 and finalized, pistons Wiseco/CP (or other) 87. 5 mm, under high compression ratio (12-13), connecting rods Carillo (or others), camshafts Skunk2 level Stage 3 (or similar), reinforced springs, receiver from Skunk2, Toda and similar, large damper 70 mm, exhaust 4-2-1 Toda, fuel pump Walbro 255, injectors from turbo Acura RDX performance 410 ss, oil pump K20A2, ECU Hondata K-Pro + trifles. Such configurations give out more than 300 hp without supercharging, the cost of realization is high, the resource of strongly squeezed motors is extremely low and often it is easier to install a compressor or buy initially faster car.

Compressor and turbine on K20A

A fairly simple way to raise the power of a standard motor is to install a compressor. For example, the popular solution Jackson Racing, at a pressure of 0.5 bar, is able to inflate up to 270-290 hp, in addition to the supercharger we need an intake/exhaust Toda, pump Valbro 255, injectors 410 ss from RDX, ECU Hondata KPro.

For a more serious supercharger or turbo we need to change the connecting rod and piston group to forged, APR bolts, the kit itself with intercooler and everything necessary on the basis of Garrett 30 (or easier), port the head, put shafts of Stage 2 level, springs, plates, exhaust, tune. At the output we will get far beyond 400 forces, but the rationality of such decisions is under a big question.

MOTOR RATING: 4