figuring out the history of the ej22

[mellow65]

im trying to put a list together of important dates in the ej22s history. I know through out the years they had a few changes to it but I want to get a list of the major ones.

 

Here is the list of stuff that I know changed and I will fill in the years as we get them

 

OBD2 - 1995 (impreza and legacy)

interference motor - 1997

roller rockers - 1995

solid lifters - 1997

single port exhaust -

 

if you know more changes that happened to them add them

 

and if you can add only if you really know that would help keep down the BS

 

the reason i start this thread is because you always get people asking the same questions about the ej22 and i was just going to put it in the USRM

[porcupine73]

Sounds like you've got these ones covered, but from http://endwrench.com/images/pdfs/2.2Liter.pdf is:

 

2.2 Liter Engine Enhancements

Beginning in the 1997 Model Year, the 2.2 liter engine for 1997 Legacy and Impreza models has had internal and external changes that yield an approximately 10% increase in power and 3% increase in fuel economy.

 

Accomplishing this involves many factors, one of which is engine friction reduction. The piston, a major source of engine friction, has been coated with a friction reducing agent called Molybenum. This thin coating not only allows smoother travel through the cylinder, but also reduces cylinder wall scuffing.

 

The skirt of the piston has been reshaped and the overall weight has been reduced by approximately 100 grams. Compression ratio has been increased to 9.7 to 1 by reshaping the crown of the piston. This eliminates the clearance that was available between the piston at TDC and the fully opened valve.

 

Piston pin offset has been changed to 0.5 mm. Piston to cylinder wall clearance has been reduced by increasing the piston diameter.

 

Another source of high engine friction is the valve train. Hydraulic lash adjusters (HLAs) are always in contact with the valves. The hydraulic pressure of the lash adjuster must be overcome during operation and during the most critical time of engine start.

 

To overcome this situation and to contribute to the total reduction of friction loss, 1997 and later SOHC engines have solid valve adjusters. The scheduled service of this valve train is set at 100,000 miles. SOHC engines now use an adjustment screw to adjust valve clearance.

[mellow65]

so it looks like in 97 they became interference motor and got solid lifters

 

so that answers 2 of mine, but I'm going to include all that tech info too

[porcupine73]

also found in the article

 

The roller rocker cam follower system that was introduced on the 1.8L Impreza engines, is installed on all 1995 model year and later 2.2 liter engines. The roller assemblies are not serviceable separately, but the rocker arms may be serviced as individual units.

 

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

[mellow65]

only one more thing to answer of mine, when did they go to the single port exhaust

[porcupine73]

Other Engine Modifications (2.2L 1997) The intake manifold has been reshaped to increase the airflow mass and speed, contributing to improved low and mid engine speed operation. Components located on the intake manifold have been relocated as compared to the 1996 models. EGR Solenoid, Purge Control Solenoid, etc.

 

1999 2.2 Liter Phase 2 Engine Enhancements (from endwrench article H-4 and H-6 service):

All 2.2 liter engine for 1999 are the Phase 2 design. The 2.2 liter Phase 2 engines are a SOHC design, with a newly-designed cylinder head. Changes in the 2.2 liter Phase 2 engines are as follows:

 

• The engine and transmission are fastened with six bolts and two studs.

• The thrust bearing has been moved to the number 5 position.

• The oil groove in the number 1 and 3 have been changed to supply additional lubrication to the crank journal.

 

Additional Phase 2 Engine Features

• The cylinder head is a two-rocker shaft, solid type valve system with roller followers.

• The valves are positioned at a larger angle than previous model years. The intake valves are positioned 23 degrees off-center with the exhaust valves

positioned 20 degrees off-center. Prior model year engines utilized a 15-degree positioning angle.

• Head gasket thickness is 0.7 mm.

• The intake rocker arms are marked so they are correctly placed on the rocker shaft when servicing. An IN1 or IN2 will be embossed on each rocker arm. As viewed from the front of the engine the Number 1 intake valve of ach cylinder and the number 2 intake valve have an IN1 marked and IN2 arked rocker arm that mates with it. New IN1 rocker arms can also be identified by a Green painted mark on the top of the rocker arm. The IN2 rocker arms have a white mark. Proper positioning is maintained through the use of a wave washer located between the rocker shaft arm and rocker arm shaft support.

• The camshaft is secured to the cylinder head with the camcase. An oil passage in the cylinder head provides the passageway in the camcase with oil

that leads to the intake rocker shaft. Oil from the camshaft is collected on the opposite side of the passageway leading to the intake rocker shaft to provide oil to the exhaust rocker shaft.

 

Note: Cylinder head and camcase must be replaced together (line bored).

• The sparkplug pipe is pressed into the cylinder head and is not serviceable.

If it becomes damaged the cylinder head must be replaced. The seals

installed onto the ends of the sparkplug pipes seal against the valve covers and should be replaced when the valve cover is removed.

• Pistons on the 2.2 liter engines have a 0.5 mm offset with the engine having a compression ratio of 10.0 to 1. The horsepower has increased to 142 hp @ 5600 RPM. Maximum torque is149 ft. lbs @ 3600 RPM.

• Camshaft sprockets are constructed of a resin type material with a metal key pressed into the sprocket for maintaining proper sprocket to shaft orientation.

[screwbaru2]

Great info Porc! I'm copying that for my records. Wife's imp is a 99 2.2

Thanks!

[EVOthis]

yeah thanks for the info......extremely helpful......