Does anyone know if you put phase II 2.5 sohc engine heads on a phase I ( 1997) 2.2 liter  (using the 2.2 gaskets) will that engine combo work?

I need to get a buddy out of a jam in his 2002 OBW by building him the most inexpensive engine i can and I dont have any good 2.5 sohc lower ends that I trust as is.

If the 2.2 phase one wont work will the phase one 2.5 lower end work?

Thanks

You can fudge some combos together to get by but in the end unnecessary risk might outweigh reward.

 

The head gaskets have to match the BLOCK.  

 

The block has to have the right number of bolts connecting engine to transmission.  Autos can mate to 4 bolt engines but manuals don't have stud for the lower starter to tighten down if you use a 4 bolt main block in an 8 bolt cars transmission.

 

The power is going to be horrible on a 2.2 with 2.5 heads but as you figured out already the intake has to match the heads.

 

It might be better in the long run to sell the Outback needing an engine, get a 1000 or so out of it and get an older model that one of your engines is intended to go into instead and fix a car with its corresponding parts.  

 

If it is just knocking take it apart, replace the crank and fix the motor instead.

 

Good luck and hope it all goes well.

What I have done before when I can't find an 8 bolt block at the junkyard is go find a 1999 Outback engine, take the heads off and put the ej25 sohc heads on that.  The pistons are wrong but they aren't hard to switch out.

Do not use the ej22e head gaskets, the coolant passages don't line up with the head. Also as Shawn said, power will be pretty low with that combo as it yields a much lower compression ratio. It is in the neighborhood of 8.7:1 which is good for a diy turbo, but bad for naturally aspirated.

What I have done before when I can't find an 8 bolt block at the junkyard is go find a 1999 Outback engine, take the heads off and put the ej25 sohc heads on that.  The pistons are wrong but they aren't hard to switch out.

what i've done in those cases is to just use a thicker headgasket to avoid swapping pistons. can't recall which gasket off the top of my head but there is one that works, either Subaru 610, Six Star, or Cometic.  i'm almost positive it's a Subaru one.

The 610 is the correct gasket for the 25d. A person could run a thinner gasket and still be ok with the piston protrusion of the 25d, and keep the compression ratio closer to stock.

The 610 is the correct gasket for the 25d. A person could run a thinner gasket and still be ok with the piston protrusion of the 25d, and keep the compression ratio closer to stock.

Will (WJM) put Phase II heads on an EJ25d block and it assembled fine, but when running the pistons hit the heads.  Installed thicker headgaskets and it didn't do it.  So I opted for thicker headgaskets when I put Phase II heads on an EJ25D block.

 

Ah - the last time I did this the heads had been milled below Subaru minimums too, so I had less thousandths to work with too.  Forgot about that.

Edited July 29, 201411 yr by grossgary

This is for a friend with little $ or I would def replace the lower end parts.

I'm guessing when you say subaru 610 you are referring to the 2.5 dohc gasket 11044AA610.

You can use the 4 bolt blocks with the 8 bolt manuals by  welding a 12mm and 10mm stud together then tap the lower transmission hole.... I've done it a couple times including my car when swapping the 2.2 sohc for a blown 99 2.5 dohc.

I have a couple good 99 2.5 dohc lower ends that i can use for this.... thanks for the advice.

Craig

 

 

also does anyone know if anyone has made adapters to go between the phase two 2.5 manifold and the phase one 2.2 block? i am about to mock some up to see how that works. 

Tap the lower starter hole in the trans for an M12 bolt and do a little trimming with a dremel in the bottom hole on the starter so the bolt fits through. Doesn't need much. If you have a 12mm drill bit that makes really quick work.

 

I've seen adapters for one of the turbo manifolds IIRC. Doesn't seem like they would be too hard to make.