Subaru EJ22: Everything You Need To Know

In 1989, Subaru started producing EJ22 for their Impreza and Legacy models. A campaign to satisfy the consumers with continuous engine development in succession and modification throughout the years.

The EJ family of engines is intended to replace the EA engines of the same automaker.

With that, how does the EJ22 sits differently among its other family member in the EJ family?

Join me to discuss details regarding the engine’s design, framework, reliability, issues, potential, and many more.

Let’s get right to it!

What are EJ22 Engines?

EJ22 engine is made by Subaru, released in 1990 for their new models – Legacy and Impreza; later, they installed it on the Outback. It is part of the expanding EJ engine family line at that time.

This engine has undergone serialized updates throughout the years of its service, including the increase in power, efficiency, and reliability for a better driving experience.

There are three significant modifications which can be subsequently seen evidently on their respective changes. The EJ22E, being naturally aspirated, is a stripped-down version of all the EJ22 engines.

It is an atmo gasoline engine with an aluminum block; it was produced from 1990 until 1996. And later, in the same year, 1996, it was updated and became the known EJ22EZ.

A turbocharged version is followed right after phase one, a 2.2 Liter SOHC EJ22T engine. Producing 165 HP, has oil squirters, fully closed deck, and no intercooler.

The phase 2 engine that succeeded the EJ22T is the EJ22G which is also a closed deck based on the EJ20K STI engine – a JDM engine. This engine still uses the same heads and turbo but has unique features for its closed-deck 2.2 Liter crankcase.

The block does not have oil squirters, factory forged pistons, and the connecting rods are stock.

Considered one of the significant changes in the EJ22 is the molybdenum-coated pistons to reduce friction and enhance its resistance to scuffing.

Engine Specifications and Design:

  • Production Run: 1989 – 2001
  • Cylinder Head Material: Aluminum
  • Cylinder Block Material: Aluminum
  • Configuration: Flat-4 (opposed)
  • Bore: 96.9 mm
  • Stroke: 75 mm
  • Valvetrain: SOHC 16-valve, Rubber Timing belt, and Resin Type Cam Sprockets
  • Displacement: 2.2 L (2212 cc)
  • Compression Ratio(s): 9.5 (EJ22E) to 9.7 (EJ2EZ, EJ222, and EJ223)
  • Weight: 265 lbs.
  • Maximum HP: 280 HP at 6,000 RPM
  • Maximum Torque: 268 lb-ft at 3,200 RPM


The first EJ22 engine was released in 1990; then, they are modified in the following years on 1995, 1997, and 1999. As we mentioned earlier, the 1990 release is an all USDM naturally-aspirated; this is the base engine for the upcoming EJ22 engines.

It featured a four-cylinder boxer engine with an all-aluminum lineup from the cylinder block up to the heads. The blocks have cast-iron sleeves installed inside, SOHC aluminum heads, and belt-driven camshafts. The compression rating of the initial EJ22 engine is 9.5.

The EJ22E naturally-aspirated produced a range of power output.

  • 1990 – 1994 release has 133 HP at 5,800 RPM and 137 lb-ft of torque available at 4,800 RPM.
  • 1995 – 1995 has 137 HP at 5,400 RPM and 145 lb-ft of torque at 4,000 RPM.
  • 1997 – 1998 has 140 HP at 5,600 RPM and 145 lb-ft of torque at 4,000 RPM.
  • 1999 – 2001 has 145 HP at 5,600 RPM and 149 lb-ft of torque at 3,600 RPM.

The effort for a much improved and developed EJ22 engine was started way back in 1997 when Subaru initiated to enhance further the performance capacities of the Legacy and Impreza models.

The reform involves internal and external changes, primarily the engine friction reduction and increasing the power as much as ten percent and three percent increase in fuel economy.

Subaru took a deep inclination that friction greatly diminishes the abilities and potential of the engine; that is why the produced pistons starting from the 1997 model years, were coated with molybdenum which reduces the cylinder wall scuffing and the moving friction.

In addition, the piston’s weight was reduced by almost 3.5 oz; Subaru reshaped the piston skirt and piston crown, resulting in the increase of compression rating to 9.7.

This change eliminates the clearance between the fully opened valve and the piston at the TDC position, transforming the EJ22 into an interference engine.

The intake manifold has also been reshaped to increase the airflow speed and mass, contributing to a better low and mid-engine speed operation. The components that sit alongside the intake manifold were relocated, such as the EGR solenoid, Purge control solenoid, etc.

Another concern for Subaru in locating high engine friction is the valve train because the HLAs or Hydraulic Lash Adjusters always come in contact and reach the valves. The lash adjuster hydraulic pressure must be contained during operations and during the engine start.

So, to surmount this situation and put a lasting effect on friction reduction, 1997 and other SOHC engines have solid valve adjusters scheduled to be serviced at every 100,000 miles.

These SOHC engines use an adjustment screw to adjust the valve clearance. However, earlier HLA engines were advised to use 10W30 or 10W40 oil throughout the year; 5W30 for engines in low-temperature regions.

The roller rocker cam follower system introduced on the Impreza engines was installed on all 1996 model year and succeeding engines. The roller assemblies are not separately serviceable, but the rocker arms can be serviced individually.

The carbon-made head gaskets with integrated O-rings are interchangeable from right to left on 1990 to 1994 N/A engines.

But the most significant and evident change of the EJ22 engines was made in the 1999 modification, the phase 2 design as they call it.

The main feature of this newly developed EJ22 is a new SOHC cylinder head with the valves positioned at a wider angle – 23 off-center intake valves and 20-degrees off-center exhaust valves. Previous engine models utilize a 15-degree positioning angle.

Changes also include the six-bolt and two studs usage for the engine and transmission fastening; thrust bearing position moving to the fifth spot, and number 1 and 3 grooves have been changed to provide additional lubrication to the crank journal.

Some Additional Phase Two Engine Features:

  • Thicker head gasket at 0.03 inch
  • The cylinder head has a two-rocker shaft, solid type valve system with roller followers.
  • The camshaft is securely placed to the cylinder head with the camcase. Subaru made an oil passage on the cylinder heads to provide a passageway in the camcase with oil leading to the intake rocker shaft. The oil coming from the camshaft is collected on the other side of the passage that leads to the intake rocker shaft to send more oil to the exhaust rocker shaft.
  • Subaru also put a mark on the intake rocker arms, making them easier to place on the rocker shaft when servicing. An IN1 or IN2 was embossed on each rocker arm. From the front view of the engine, the number 1 and number 2 intake valves of each cylinder have an IN1, and IN2 marked rocker arm that connects that matches with it. Newer IN1 rocker arms can be identified by a green painted mark on the top of the rocker arm; the IN2 arms have a white print. Proper positioning is vital and should be maintained by using a wave washer situated between the rocker arm shaft support and the rocker shaft arm.
  • The camshaft sprockets are made of a resin material with a metal key pressed into the sprocket to maintain the correct sprocket to shaft orientation.
  • The engine pistons have 0.020 inch offset for the engine having a 10.0 compression rating. A noticeable power increase to 142 HP at 5,600 RPM and 149 lb-ft of torque at 3,600 RPM.

Applications of EJ22E engine:

  • 1989 – 199 Brighton
  • 1993, 1997, and 2001 Impreza


The EJ22T is the turbocharged version of the EJ22 engine. It is a phase one SOHC Turbo that produces 165 HP, no intercooler, a fully-closed deck, and has oil squirters. This engine was equipped with the 1991 – 1994 USDM Subaru Legacy, with only 8199 models available for the United States.

The 4-door sedan is called the sport sedan, and the 5-door wagon is called the touring wagon. The wagon was sold as an automatic, but there were many more automatic-equipped models than 5-speed sedans.

Subaru made a DOHC variant to produce 276 HP at 6,000 RPM and 268 lb-ft of torque available at 3,200 RPM. This engine appears in the Impreza Sti 22B GC8 series (JDM)


The EJ22G is based on the EJ20K STI engine and also a phase two closed-deck engine. It uses the same cylinder heads and IHI RHF 5HB turbocharger but with a more distinctive closed-deck crankcase.

Even though it is a closed-deck, it does not have an oil squirter for piston cooling, contrary to the EJ20 closed deck block and the USDM Legacy EJ22T, also a closed-deck block.

The pistons of EJ22G are factory forged items, and the connecting rods are stock. The initial rating of the engine coming from the factory was penned at 280 HP. But due to the ‘Gentleman’s agreement, Japanese automakers cannot advertise power production beyond the 276 HP mark.

However, some enthusiasts say that the EJ22G engine is capable of 305 HP and has a lower compression rating of 8.0.

Engine Tuning, Upgrades, and Modifications

EJ22 is a good engine swap, especially the closed-deck ones; they are the most robust, most reliable, and incredibly rare. You can find this engine if you have the right connections, and the price is definitely up there.

The engine potential of the EJ22 engine, as a collective, is also outstanding. The naturally-aspirated can be tuned, and the ECU can be configured, resulting in a 15-25 HP gain.

However, putting a turbo in your naturally-aspirated engine is not practical and can rip the pockets. With that, you should opt for the turbocharged version to save more money to buy other performance parts for the exhaust, intake, internals, etc., and also has more power and torque.

Problems Surrounding the EJ22 Engine:

EJ22 is one of the most reliable, durable, and efficient engines made by Subaru – a bulletproof one if you will. Spanning 300,000 miles or more for its service life, we cannot erase the fact that this engine has clear intentions to outlast every engine at its competition.

It also has strong internals and cannot be swayed by any external factors.

You just need to adjust the valve clearances.


The Subaru EJ22 engine is probably the most reliable machine that Subaru made. With an engine life lasting more than 300,000 miles, even reaching 500,000 miles without any problems or issues, definitely a worth it investment for an engine of this caliber. Even with a small profile, this engine digs.

Apart from that, EJ22 is also a suitable engine swap medium and delivers the power the vehicle needs. It has no severe or insurmountable problems even in the longer run.

Its development was carried on for many years and well-updated throughout its tenure, so the technologies integrated into this engine are not far from what we have today.

If you have the cash and can get your hands on this powerhouse engine, I bet that you should grab the opportunity as this machine is not so common these days and is harder to come by.

I hope that the information and discussion we have here helped you understand the Subaru EJ22’s engine design, issues, applications, developments, upgrades, potential, reliability, and overall impact on the automotive industry.

2 thoughts on “Subaru EJ22: Everything You Need To Know”

  1. Every time I go to reading about my car it’s Irie. Sweet write up! I appreciate the context and the enthusiasm! I had the cash and I bought a 95 LS Brighton Wagon 4auto AWD this year. “You just need to adjust the valve clearances” that’s good advice. Car is looking at some repair work but its really holds up well with the highway mileage, the mild weather between Florida/California. Car has also gotten some TLC through its time.

  2. The EJ22E is perhaps the best Subaru engine ever made, however you might have gotten the dates wrong for it. I have a 98 legacy built in October of 97, It has a
    Phase 1 EJ22E with single port exhaust and an egr pipe. The last year phase 1 (96-98) were single ports, had 9.7:1 compression ratio, and many more upgrades. Thought to let you know!


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