Head gasket: which one?

[Marnix]

I'm currently building a new engine for my track car. I'm using a EJ22 open deck short block and MY90 JDM DOHC Legacy Turbo heads. Don't ask why, I just happen to have this combination laying around.

Question is what head gasket to use, regarding alignment of cooling passages.

MY91-94 USDM EJ22T? I know the standard early MY SOHC gaskets won't work. What about the Phase-2 thinner gaskets, anyone have a picture of one?

And just out of curiosity, any pics available of closed deck EJ22T heads or engine deck?

Any help is appreciated.

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[Marnix]

Already found what I was looking for; the USDM EJ22T head gaskets match the coolant passages of the JDM EJ20G heads.

[White 2.5rs]

graham did you use a HG for 99rsheads of that stiblock?

alex

[Scoobyslack1]

Originally posted by Marnix
Already found what I was looking for; the USDM EJ22T head gaskets match the coolant passages of the JDM EJ20G heads.

really.....you confirmed this? any pics?
I'm putting EJ20G heads on my legacy turbo short block......this will save me doing some research

[Marnix]

Well, I compared the pictures of the closed deck EJ22T block that Wedge posted a few months back, and coolant passages are 95% identical to the closed deck EJ20T engine that I have in sitting my basement. The heads I want to use came off that engine. So basically, it's 1+1=2 but I still want to check with the head gasket just to make sure.

Please note that if you put early Legacy Turbo EJ20G heads on the stock EJ22T block, you'll end up with a compression ratio of 6.7:!

I'll be running stock EJ22 pistons, which will give me compression ratio of 7.7:1, perfect for some serious boost capabilities!

Both calculations based on info on EJCALCS and the 57cc of head volume I have measured on my EJ20G heads. Both with 1.52mm gasket thickness.

If I can find info on cooling pattern of later, thinner (0.58mm) EJ22 gasket (that is compatible with the EJ20G DOHC heads), I will use that to reach a calculated CR of 8.3.

Anyone have a thin EJ22 gasket laying around and willing to take some pics?

[Scoobyslack1]

Originally posted by Marnix
Please note that if you put early Legacy Turbo EJ20G heads on the stock EJ22T block, you'll end up with a compression ratio of 6.7:!

I thought it would be about 7.8:1...
I must look into this further.....I don't want to loose all that nice torque I have now

[Marnix]

Don't give up just yet, there's a difference in head volume between MY89-93 Legacy Turbo EJ20G DOHC heads, and the later MY93 and onwards Impreza EJ20G DOHC heads (later version EJ20K) and Legacy TwinTurbo heads (EJ20H on 260bhp auto and EJ20R on 280 bhp manual).

The 'first generation' heads are 57cc, and the 'second generation' EJ20H heads (similar to later EJ20G and EJ20K and EJ20R heads) that I have measured aswell, are around 47cc. This is due to the different valve angles.

EJ22T stock pistons with Gen1 EJ20G heads -> CR = 6.7
EJ22T stock pistons with Gen2 EJ20G/H/K/R heads -> CR = 7.4

It may well be that EJ25 DOHC heads have the same head volume as the Gen2 EJ20G/H/K/R heads, as EJCALCS mentions 46cc, which could well be down to my crude measurements.

[Scoobyslack1]

I haven't given up hope......besides the heads I have are adorned with some nice titanium springs

[White 2.5rs]

ru sure theyre titanium and not steel w/ titanium retainers?

[Scoobyslack1]

well, I paid Axis tuning to put in some titanium springs w/STi retainers.....so I hope they are

[Marnix]

Anyone has a supplier for thinner - 1.00mm - gaskets instead of the standard 1.52mm parts? For EJ22T obviously.

[inpreza kid]

try cometic. they make several headgaskets for the ej22t. you can go custom too.

[Graham]

I used the EJ25 Cometic's