engine block compatibility? curiosity question

[sirtokesalot]

whats the difference between a 95 2.2 block and a 2001 2.5 block? is it possible to merge the 2 engines together using the 2.2 block and run it in the 2001 outback?

[idosubaru]

you can swap almost any EJ short blocks. 

Its been years since I’ve done 00+ heads on 90s block, it’s not a common solution. I don’t recall any issues. I’ve had to use thicker headgaskets before but I don’t think it was for these swaps. 

01 heads on 95 block will be low compression in addition to lower hp smaller block in a heavier vehicle. 

 

[sirtokesalot]

1 hour ago, idosubaru said:

you can swap almost any EJ short blocks. 

Its been years since I’ve done 00+ heads on 90s block, it’s not a common solution. I don’t recall any issues. I’ve had to use thicker headgaskets before but I don’t think it was for these swaps. 

01 heads on 95 block will be low compression in addition to lower hp smaller block in a heavier vehicle. 

 

is there a head combo that would not lower the compression and still work? i wouldent mind a little less power as long as it runs and drives reliably and possibly retain the non interference bit if possible. its mainly a thoght for now as my 2.5 still runs but my 2.2 block was one of the quietest subaru engines ive ever heard. it had no internal knocks or piston slap sounds.

[el_freddo]

With that block/head combo you’ll more than likely lose the non interference “feature”. 

That’s nothing to be scared of - just do your timing belt kit in the given intervals and use a quality kit. 

The 2.5 heads on a 2.2 block will create that funny mushroom combustion chamber to cylinder wall shape. I don’t fully understand why it’s an issue though.

Cheers 

Bennie

[idosubaru]

12 hours ago, sirtokesalot said:

is there a head combo that would not lower the compression and still work? i wouldent mind a little less power as long as it runs and drives reliably and possibly retain the non interference bit if possible. its mainly a thoght for now as my 2.5 still runs but my 2.2 block was one of the quietest subaru engines ive ever heard. it had no internal knocks or piston slap sounds.

If you’re willing to do a block swap I’d knurl or replace the pistons in the EJ25 and keep that instead of swapping blocks.

[sirtokesalot]

8 hours ago, idosubaru said:

If you’re willing to do a block swap I’d knurl or replace the pistons in the EJ25 and keep that instead of swapping blocks.

well the idea was that i have the ej22 block and figured i could get that engine running with the cost of head gaskets.

[sirtokesalot]

i do have another ej25 engine but it had low compression and misfired pretty bad thogh it did run and not make any odd sounds. how likely is it that the block is fine and the compression issues were int he heads?