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ej22 engine with 2.5 heads???


85cobra
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Compare the 2.2 HG to the 2.5 head - there may not be enough material to seal against the fire ring. You can usually put a smaller bore head on a larger bore engine but to go the other way invites problems with combustion chambers too large to seal against the HG properly. Also the 2.5 heads will probably have some differences in the cooling ports that may not line up well with the 2.2 HG.

 

Even if it will work with the HG.... I'm not sure of the compression ratio. So you will have to do some research there. It will likely be a bit too low. The tendancy was toward larger combustion chambers in later years so you might end up with an engine great for turbo-charging but completely gutless on it's own.

 

Generally crossing the phase-I and phase-II boundary with blocks and heads is not done. There are some exceptions but all of them involve smaller heads on larger blocks.

 

You may be able to use phase-II 2.2 heads. Those would be a better fit and would mate up to your manifold.

 

GD

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Phase I EJ25 blocks install into EJ22's just fine.

 

I have installed Phase I EJ25 blocks in Phase II EJ25 vehicles. Pistons will strike the heads if you don't use a thick headgasket.

 

So if a Phase I EJ25 block can be installed in a Phase II EJ25 vehicle and your EJ22 heads will bolt up to a Phase I EJ25...there is hope.

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Thanks. But the block is 2.2. And the Heads are 2.5. Block is from a.96 impreza. And the 2.5 heads is from.a.00 legacy gt limited.

Only reason why im.asking is because the shop said ghe 2.2 heads have low volume. And two of the valves have a little rust around the rim.

So i have a set of the 2.5 off my other motor.

 

Im new to the subaru game. I've always had mustangs. So please understand why im lost.

I'll take suby 101 please. LoL. :clap:

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you deserve a metal for searching so well, good job!

 

On one of the post on here stated, That getting a replacement from yrs 96-01.
that thread you linked to says nothing about later model 01 vehicles. 96-01 is nowhere to be found.

 

but if you do find such a statement you can disregard that completely - that is not even close to true or of any value to you at all.

 

the EJ22 changed completely in 1999 and is not interchangeable with earlier EJ22's. the EJ25 also changed in 99 or 00 (depends on vehicle) and is also not interchangeable with earlier EJ25's.

 

now by "not interchange" i mean plug and play swap....but if you're talking swapping heads, blocks, etc it starts to get far more complicated because of all the changes and i don't have time to write a book.

 

as GD said the intake manifolds change in 99 so it's not a simple swap when yo'ure talking about swapping heads.

 

you can work around it but for an easy swap you want to keep the heads with the vehicle.

 

which is what you're asking i think - keep the 00 heads on the car and bolt them to the EJ22.

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I think that the valve area is too large for the smaller diameter piston bore.

 

But that would be the only "no way" problem.

 

If the valves fit within the firering of the 2.2 headgasket, then you could do it.

 

It may have a low compresion ratio, but otherwise I would guess it would run pretty well.

 

No clue about horsepower:popcorn:

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Thank you. I will check to see if this will work. Which i hope it does.

Seems either way im going to have low compression. Machine shop said the 2.2 heads have slightly low compression.

But anyway here is the Clean 2.2 head & 2.5 lightbox?id=7675216154

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With low compression it's going to be rediculously underpowered. The '00 2.5 had 165 HP. The 2.2 has 137 and with low compression it's probably going to struggle to hit EJ18 performance which is 110 HP.

 

You should find another EJ25. The EJ22 in that car with low compression heads is going to be scary to drive.

 

GD

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i put a 91 2.2 in a 2003 impreza other day just the short block and used the 2.5 shoc heads and intake had to use 2.2 turbo gaskets and slightly modify them and the timing belt was a little tight had to trim the adjuster a slight bitt ran very good and still running no problems dident even notice any power diferance and the girl saved over 2000$ on the job 2.2 bottom end 500 $ 2.5 bottom end 2500$ and the 2.2 bottom end is way stronger

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i put a 91 2.2 in a 2003 impreza other day just the short block and used the 2.5 shoc heads and intake had to use 2.2 turbo gaskets and slightly modify them and the timing belt was a little tight had to trim the adjuster a slight bitt ran very good and still running no problems dident even notice any power diferance and the girl saved over 2000$ on the job 2.2 bottom end 500 $ 2.5 bottom end 2500$ and the 2.2 bottom end is way stronger

 

Thank you. I will try to find thinner gaskets to raise compression, i was afraid that the 2.5 were slightly off. So i am going to have to put them close up to the block to make sure all ports line up. Correct.?

Anything else i should know?

and which year of 2.5 sohc heads did u use?

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The gasket ports will not line up. That's why trimming is needed.

 

Ivan is saying he used 2.2 Turbo head gaskets which are composite not MLS style gaskets. They would be much thicker resulting in even less compression. But they would be easier to trim for the cooling ports being graphite composite gaskets.

 

The gasket thickness will space out the heads farther than normal - resulting in the timing belts being tight. So it makes sense he had to modify the belt tensioner.

 

He stated the year - 2003 Impreza. Which would be an EJ251 - so that's the heads he used.

 

Seems like a lot of work but if Ivan says is works then I would be inclined to believe it. Though an Imp is going to weight a lot less than a Legacy GT so the decrease in performance would be less noticeable.

 

GD

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