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Can I use different heads on a gen1 2.5?


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Sorry I should have said that, It is a 1996 outback 2.5 DOHC auto tranny. I think it has a burned valve? It has 190,000 on it, The head gaskets were replaced and ran fine when I bought it but now throws a code on #3 cylinder, and has low compression in that hole.  I am planning on doing a 2.2 swap in the car, but trying to learn as much as I can about what I have, if that makes any sense. From what I have learned the engine I have is the worst Subaru ever built and wondering if a SOHC will work on it? The engine still runs good and a may help someone out of a jam that really needs an engine and can`t afford to do a swap! I`m just wondering if there are any options.  Thanks

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Any 2.2 heads or do they have to be from certain years? What about the intake manifold matching up? or do you use the intake from the 2.2 and the wiring harness from the 2.5 intake? Like I said this is all new to me, I find it fascinating what all people do to their Subarus and that there are sooo many people out there willing to help.  Thank you all!!! 

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i'd ditch the EJ25 and install a complete EJ22, ready to go.

you can get an entire EJ22 for $300 or less.  www.car-part.com or a bunch on ebay for $300.

sell your EJ25 block for that or more and you've got zero dollars into the repair and end up with a more reliable engine with less work to do to.

 

 

Use a intake from a 97-99 impreza or legacy 2.2 preferably with egr

 

***CORRECTIONS:
1. 1999 EJ22 wont' work - it's Phase II (well, not without a lot of work)

2. 1996-1998 EJ22's will work but also require you getting a single port EJ22 exhaust manifold (easy to swap in place as it has to be unbolted anyway, just make sure you can get one, some yards won't sell them).

 

Ignore SOHC and DOHC for this discussion, it doesn't matter.  EJ22's are SOHC  and EJ25's are DOHC but they're completely plug and play interchangeable, it's benign.

 

Any 1995-1998 EJ22 intake will all bolt up to EJ22 heads.  preferably with EGR as ivans said as all EJ25's have EGR but not all EJ22's do.  just have to look and see.


Simplest approach, plug and play into your EJ25:
1995 automatic (they all have EGR) heads

1995-1998 intake manifold

 

Another option:
1996-1998 with EGR ( you have to look, no way to tell otherwise).

1996-1998 single port exhaust manifold

1995-1998 EGR intake manifold

 

Alternate option if you don't care about the check engine light/EGR situation:
1995-1998 any EJ22 heads and intake manifold

Single port exhaust for 96-98 heads

 

The car runs and drives fine if you install heads/engine without EGR, you'll just have a check engine light.  It doesn't matter in my state so i prefer them without EGR so it's a cleaner install, less parts.

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Heads from a 95 2.2 will have an EGR and dual port exhaust. They'll just bolt right up.

 

If you search "frankenmotor" you'll find tons of info.

can you edit that ***incorrect*** - 1995 automatic EJ22 only have EGR.

1995 manuals do not have EGR.

 

later years are hit or miss and have to be visually inspected, though later automatics appear to often have EGR, i've seen some that don't.

Edited by grossgary
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Any 2.2 heads or do they have to be from certain years? What about the intake manifold matching up? or do you use the intake from the 2.2 and the wiring harness from the 2.5 intake? Like I said this is all new to me, I find it fascinating what all people do to their Subarus and that there are sooo many people out there willing to help.  Thank you all!!! 

 

Swap the Throttle bodies too and this would be the way to use any 2.2 manifold.

 

 

 

Otherwise you have to get a 2.2 intake from 95-98......and to have it throw no codes either way you will need an EGR manifold and heads or drill tap which on some can be done and others can't

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