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Phase 1 vs. Phase 2 EJ-series 4-cylinder engines

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Phase 1 vs. Phase 2 EJ-series 4-cylinder engines

Phase 1 and Phase 2 refer to the Engines, Transmissions and Electronics used in Subarus (aka, Phase I and Phase II).  It does NOT refer to body styles or Generations of each model.

See Wikipedia for more EJ-series info. https://en.wikipedia.org/wiki/Subaru_EJ_engine

Note: This pertains to US Domestic Market (USDM) models only. Japanese Domestic Market (JDM) and other overseas markets had more engine choices, but generally the Phase 2 started the same time. The older JDM models were usually a year ahead of those available in the USA, at least for the Legacy model. Subaru established their USA assembly plant in 1989 in Indiana.

Phase 1: All Subaru 1.8 (EJ181), 2.2 (EJ22E, EJ22EZ), 2.2T (EJ22T), and 2.5 (EJ25D) engines from 1989-1998, including the '91-'94 Legacy Turbo and '99 Legacy Outback, SUS and GT*


       *The 1999 Legacy OB, SUS and GT’s EJ25D used a Phase 2 shortblock BUT with the Phase 1 ’96-’98 2.5 pistons, DOHC heads, Intake Manifold and engine harness. It also had the Phase 2 4EAT Transmission.

Note: The 3.3 (EG33) in the SVX is considered a Phase 1, I'd think. Side-note: The SVX's infamous 4EAT transmission can be upgraded w/the '96-'98 4EAT from the OB or GT as they can support the power of the 3.3 (probably), but they have a much shorter (?) 4.44 FD ratio so the rear differential must be swapped too. A 5-speed swap would be better yet! Either transmission will bolt-up the 3.3. Check out www.subaru-svx.net for the details.

Phase 2: All Subaru 2.0 (EJ205), 2.2(EJ222, EJ223) and 2.5 (EJ251, EJ253, EJ252) engines (incl. turbo versions – EJ255, EJ257) from 1999-2010 (depends on model when the new FA/FB-series engine were 1st used).


More info:
- The Phase 1 EJ22E and EJ22EZ had at least 3 variations from ’89-’98.

  •     The ’89-’95 (EJ22E) were DUAL-port exhaust vs. SINGLE-port on the ’96-’98. (1996 was still the EJ22E, AFAIK).
  •      In ’97-’98 (EJ22EZ) Subaru changed to different piston for higher Compression  Ratio and SLA on the valve lifters.


Notes about swaps:
- The Intake Manifolds (IM) on PHASE 1 2.2 and 2.5 do NOT interchange/swap with each other or Phase 2.

- The IM on the PHASE 2 SOHC and DOHC ‘might’ interchange w/some slight modification – I’ve read conflicting reports on this. The ’99-’01 2.2 SOHC and ‘99+ 2.5 SOHC will interchange. Edit from RS25.com post: "All the turbo DOHC manifolds <assuming Phase 2/II> WILL bolt up to the Phase II SOHC heads. You have to use the TGVs, TGV deletes, or a long runner manifold, but they WILL work."

- The sensors, IAC, Throttle body, injectors, ECUs, wiring harness plugs, etc are different between Phases, which prevents the easy swaps. The shortblocks (no cylinder heads or IM) can be used across phases in 'most' cases.


- The '99 Legacy OB/GT/SUS EJ25D can be swapped for the earlier Phase 1 SOHC EJ22e engines from '95-'98 (and even the '89-'94 2.2, w/more work). Remember there will be EGR issues if you use a NON-EGR equipped 2.2 (usually 5-speeds), but HERE IS A WorkAround. Also, you'll need the single-port exhaust manifold / header for the '96-'98 2.2. The transmission can NOT be swapped for an earlier year.


-The Phase 2 EJ25x NON-turbo engines include the PZEV variants. I've read - no proof - that these are unique and should not be used as a source for a short block in NON-PZEV cars.


Info on the Phase 1  EJ22E used from ’89-98: http://sl-i.net/FORUM/archive/index.php/t-16437.html


From Wikipedia:
Changes in the 2.2-litre Phase 2 engines are as follows (most if not all of these updates were applied to the 2.5 engines as well):
• 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.
• Many changes to the cylinder head and camshafts (specifics on Wikipedia)
• Different pistons with a Compression Ratio of 10:1
• Different Camshaft gears / sprockets

- Additional Phase 2 transmission info:
• Transmissions acquired an external spin-on filter. Designed to last the life of the transmission.
• Different internal electronics
• 2-4 brake band from Phase 1 was replaced with a 2-4 clutch pack
• The valve body went from using five solenoids to seven solenoids
• From here: http://www.searchautoparts.com/motorage/powertrain-pro/many-changes-subaru-4eat
• Note that starting about 2004 in the Forester XT, the Phase 2, Version 2 came out.


More EJ 2.5  in = EJ25D, EJ251, EJ253

NOTE: I can't verify this as it was pulled from online info.

1998 .. DOHC ... same as in the 97-99 Legacy Outback .... MAF 
1999 .. SOHC ... with MAF and only year for these engine controls ... unique MAF and O2 sensors
2000/01.. SOHC MAP ... put these alone as they are identical
2002/04 .. SOHC MAP ... moved PCV to rear bell housing .. other minor changes, some with electronic EGR
2005 ... SOHC .... similar to previous, but unique like 1999, first year for NA Drive by wire and unique engine controls again (NO i-AVLS cams)
2006-2008 ... MAF controls ..... Changes also to exhaust, water pump and some timing components, Valve timing added to intake (i-AVLS), oil controlled, different than Turbo
1999-200X ....The Camshaft and Crankshaft sprockets (that the Tbelt runs on ) may need swapped out depending on year AND whether it's Manual or Automatic transmission. Search on here/online.
BUT the shortblock from 1999 - 2008 remains the same.

Edited by wtdash
add 2.5 info
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