EJ20K VS Late Ej20G

[RB2B]

Sticky In The Pre-2002 Thread!!!

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[AWD P & A]

When I get a chance next I'll go back and edit my first post. I've done more comparisons on these two since then that I haven't posted yet.

I'm glad I finally got a sticky thread

[rob]

At the head of your post, can you list out the observed differences?

[AWD P & A]

Sure! I plan on going back and adding everything from injectors all the way to internals.

[cmyles]

Is this thread only about the Heads?
What about blocks?

I know that EJ20K are Open deck? Or Semi ?
as opposed to Ej20g which, most are closed deck motors.

[Cbgrandtheftauto]

Sorry I haven't been able to fix this thread..I'll get on it ASAP.

To answer your question theres not much difference on the blocks..

20k- forged internals, open deck
Late G- open deck, cast pistons and rods

The early 20G blocks were closed deck until like 93-94ish

[Marnix]

Of the regular WRXs only the manual 1992-1993 GC8A WRX had a closed deck block.

After that the closed deck block was a special option of STI version 1 and 2 and only standard on the 1994-1996 WRX type RA versions with light weight valve train heads (I believe they also had the 5th injector).

All other GC8/GF8 engines are open deck including the 1999-2000 EJ207.

All rods on all GC8/GF8 engines are the same (which are nothing special, they are identical to non-turbo USDM EJ18/22 rods).

All WRX had cast pistons, except:

1994-1996 EJ20G WRX type RA (mentioned above)
1997-1998 EJ20K WRX STI / STI RA
1999-2000 EJ207 WRX STI / STI RA

All other EJ20G, EJ20K, EJ205 and EJ207 GC8/GF8 engines have cast pistons.

[2slofouru]

So what would be the difference in the heads and cams of a normal wrx ej20k and ej20g? I've also heard of RA non sti so would the heads just be normal k and g in those cases? I see information bouncing back and forth in this thread.

[2slofouru]

Another bump of hope. I have valvetrain from ej20k and ej20k sti heads and the valves in both are identical, low magnetic exhaust and normal high carbon steel intake. The spring retainers are of course different because the sti has shim under bucket. I plan on replacing the valves, springs, and retainers and retaining the shim under bucket arrangement. What I'm wondering is why the normal k heads have a 48mm long spring whereas the sti springs are 56mm? I'm looking for single (non dual) aftermarket springs, retainers, and valves for the sti heads and am not sure which to use at this point.

[ciper]

Originally Posted by Matt Monson

But riddle me this... These are EJ20K STI heads with shim under bucket. What about just plain standard Ej20K heads with shim over bucket. Wouldn't those be the same as those late Ej20G heads? Isn't it only because these heads are STi that there's any difference at all between the two castings?

I think you are right. Only the STI, Spec C, Type RA heads have the shim under bucket from what I know.

If anyone cares I just converted a set of those shim under bucket to solid buckets like what is used on the MY04 and up engines. There was BARELY enough room to grind the valves to spec once the retainers were replaced meaning all of my shims were in the 488-499 range

[2slofouru]

This section (pre-2002 factory turbo powertrain) needs a sticky section with compiled good (true) specific information on head and valvetrain specs for the pre 02 turbo ej's instead of random conjecture and opinion. There is always so much searching required for the pre usdm turbo information but it rarely leads to anything solid.

[Marnix]

It's really easy. Heads for 1997-1998 DOHC turbo are as follows:

EJ20G: shim over bucket, normal valves and springs, all same as USDM EJ25D except for the cams
EJ20K: shim over bucket (same as EJ20G), specific EJ20K valves and springs, specific EJ20K cams
EJ20K STI: shim under bucket (unique for EJ20K STI and 22B), same valves as EJ20K, specific EJ20K STI springs, retainers, same cams as stock EJ20K

The castings for the above heads are nearly identical, so if you want to convert to aftermarket setup use USDM EJ25D setup. If you want to use shimless buckets use the 2004-2008 EZ30R exhaust buckets they are 33.0 mm in diameter, same as the 1997-1998 EJ20G and EJ20K buckets.

[ciper]

I'm pretty sure EJ25D was the same as the EJ20K (late EJ20G possibly). The EJ25D has solid lifters. EJ25D has single bolt coil attachment. EJ25D has plastic cam gears. Look at the valve covers
Here are pictures of some EJ25D heads.

http://imageshack.us/photo/my-images...082239fg3.jpg/
http://i4.photobucket.com/albums/y10...s/IMG_3591.jpg

Then the first picture in this thread is EJ20k- http://forums.nasioc.com/forums/show...9&postcount=32


You dont need to use EZ30R buckets specifically. MY04 and up shimless buckets are the same and much easier to find I converted my STI ej20k heads using standard 2005 STi buckets I had. (with regular retainers of course). I honestly think the EZ30R buckets are the exact same parts with a different part number. It's too weird they are the EXACT same price down to the penny and are identical in appearance.

Edit: Haha already a thread about this - EJ25D w/ EJ20K Heads?

[ciper]

If anyone has some extra EJ20G/K cams and some extra valves I would be interested in them. Another shop screwed me over and threw away a set of Spec C RA heads I had
I have a full set of EJ20 shim UNDER buckets I could offer in trade if you're interested. Thats 16 of the special buckets, retainers and little shims.

I want to crosslink this thread here -
Differences in Ej20G and Ej20K

[2slofouru]

Thanks Marnix, for adding some useful information. It's good when a knowledgeable member gives factual information based on what they know to be true rather than saying "they appear to be", "most likely", "seems like", or "we'll settle on" in front of technical information. Based on your reputation here and your demeanor since I've been a member here, its easy to trust your input

[Marnix]

Thanks. It helps I have first hand experience with all factory DOHC turbo engines to date especially the 90s JDM engines. It also helps I have the JDM FSM ('New Model' book) and the EUDM and JDM factory part catalogues (CD-ROM).

[kimokalihi]

Good info thanks. What is the difference between 20k and 20g cams? I've got a 97 forester 20g and I'm planning to put my 257 block together with these heads. Are the 20k cams better?