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SeanDead 02-10-2010 01:24 PM

2002 EJ25 back to EJ20 ?
Hey guys, I'm fairly new to the WRX tuning world. Not so new to the tuning scene.

Anyway, ill get to the point.

I just bought a 2002 WRX (vin code correct) It says it had a EJ205AW3B9
Tanny says TY75VN2AA.

Pretty much, i bought it from the guy that said it probably had a blown head gasket, So i ended up taking the block out, to check for a blown head gasket .

Well, to my surprise, i find that cylinder #3 (It has a reputation) has rough spots on the wall, and signs of blow by.

My prognoses, it was a EJ25RS block (newer?) Its stamped with EJ25. That has non turbo pistons ect, That was converted to a turbo block. and i think thats why it got blown. It also has DOHC, which isnt stock for the 02 WRX.

It has signs of oil in the coolant, and coolant in the oil. I checked the metal gaskets, no signs of a blown one.

So i have three options, I could spend the money rebuilding, rehoneing the EJ25 block, new actual turbo pistons, resurface the DOHC heads.

Or i can buy a JDM low mileage EJ20 turbo short block, sell my DOHC heads and put SOHC. on there for gas milage, and better internals

And i will leave my number 3 option to you guys.

Whats your opinion? EJ25RS or EJ20 turbo block?

Bloth blocks and wiring harnesses/manifolds ect should work between each block right?

I appreciate it.

mosc 02-10-2010 02:16 PM

well, I am not following what's under your hood. Assuming you had the proper heads from the EJ205, I'd say build an EJ205/EJ257 hybrid. Sounds like your whole EJ205 was ripped out in favor of some never-should-have-been-turboed 2.5RS motor? In that case, you'll need something more complete so a used EJ207 sounds like a very good idea. What's under your hood? Did they even use a TD04 turbo/wrx intercooler?

SeanDead 02-10-2010 02:22 PM

Its the 2002 WRX, The only thing i notice that isn't the same is the block, 2.5RS With DOHC (I don't know how to tell what kind of cams it is from) it has the TMIC intercooler/TD-04 turbo, everything.

I've had a lot of people tell me get a closed deck 2.5
but a lot swear by the EJ20 closed deck turbo.

I do intend on adding boost to it.

mosc 02-10-2010 02:26 PM

First of all, the EJ257 and EJ207 are not closed deck. It's semi-closed. The last real "closed" deck turbo motor is the EJ22.

I don't know what kind of heads you have. If you need to replace them, get a JDM motor. If you don't, grab a EJ257 shortblock (usdm sti) and go from there.

SeanDead 02-10-2010 02:33 PM

Sorry, I ment semi closed deck. Lol

Ill look into it, Thanks.

WTRacing 02-10-2010 03:37 PM

it sounds to me that someone already had a hybrid in there and the 02 wrx was dohc you need to get the casting number off the heads but i think your gonna find that they are ej205 heads

SeanDead 02-10-2010 04:50 PM

[quote=WTRacing;240014]it sounds to me that someone already had a hybrid in there and the 02 wrx was dohc you need to get the casting number off the heads but i think your gonna find that they are ej205 heads[/quote]

Were are the casting numbers located at?

I.e any examples?

I've seen a few stamps but nothing sufficient..
Thank you.

WTRacing 02-10-2010 05:53 PM

they are on the exhaust side should look something like this


SeanDead 02-10-2010 08:35 PM

LH or RH and it says B 004

Those are the only stamps on it.

Which means?

WTRacing 02-11-2010 01:38 AM

im 99% sure its ej20 heads

mosc 02-11-2010 11:02 AM

Then grab an EJ257 shortblock.

WTRacing 02-11-2010 06:06 PM

get a shortblock stock or built and call it a day

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