Welcome to the North American Subaru Impreza Owners Club Thursday August 21, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Pre-2002 Factory Turbo Powertrain

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 07-07-2012, 08:23 AM   #1
renhoek
Scooby Newbie
 
Member#: 71339
Join Date: Sep 2004
Chapter/Region: International
Location: Victoria, Australia
Vehicle:
1995 WRX STi RA
1995 WRX STi LS1

Default 2litre piston interchangeability

Hi guys. Does anyone have an idea of which pistons can go into my V2 sti? Specifically, can later model GD sti units (eg 2003 model) go in as direct replacement? Do the rods also have to be changed?

I am lead to believe they are not directly interchangeable as the pin to crown heights are different, but just wanted your views...

Cheers
* Registered users of the site do not see these ads.
renhoek is offline   Reply With Quote
Old 07-07-2012, 01:06 PM   #2
seangfy
Scooby Newbie
 
Member#: 242150
Join Date: Mar 2010
Location: nor cal
Vehicle:
1993 impreza L ej20g
aquafrost blue

Default

I do believe that you cant use later pistons without compression and deck height issues but I could be mistaken
seangfy is offline   Reply With Quote
Old 07-07-2012, 06:13 PM   #3
renhoek
Scooby Newbie
 
Member#: 71339
Join Date: Sep 2004
Chapter/Region: International
Location: Victoria, Australia
Vehicle:
1995 WRX STi RA
1995 WRX STi LS1

Default

Yeah, I am thinking the same. If the pin to crown height is less for the newer pistons, then maybe they run a different length rod to compensate, thereby keeping to original overall lengths for the piston/rod combo.

I've got some GC8 stuff lying around. I will measure. Maybe someone has some GDC (say 2003/4) rods they could measure and post.

I sure like the smaller mass of the later pistons and would like to use them in my V2 rebuild if I can.
renhoek is offline   Reply With Quote
Old 07-07-2012, 11:40 PM   #4
pmugabi
Scooby Newbie
 
Member#: 280926
Join Date: Apr 2011
Default

The newer pistons can be used. You simply need to use the same thickness headgasket as is used in the engine that the piston came from.

Rod lengths are the same for all 2litre engines.
pmugabi is offline   Reply With Quote
Old 07-08-2012, 04:54 AM   #5
Marnix
Scooby Specialist
 
Member#: 51480
Join Date: Dec 2003
Chapter/Region: International
Location: The Netherlands
Vehicle:
1984 AM5, 1994 BC4,
2010 BR5

Default

Yes but you cannot use the V2 rods with later GD STI pistons, you will have to use the GD STI rods aswell (although same length).
Marnix is offline   Reply With Quote
Old 07-08-2012, 06:03 AM   #6
renhoek
Scooby Newbie
 
Member#: 71339
Join Date: Sep 2004
Chapter/Region: International
Location: Victoria, Australia
Vehicle:
1995 WRX STi RA
1995 WRX STi LS1

Default

Got it. So GD series pistons can go into GC engine, but have to use GD rods as well.

So if you get aftermarket pistons for the sti, eg CP, it sounds like their GC and GD pistons must be different. Is that right? I got the impression from CP that all their WRX STi pistonsnwerenthe same part number SC7400. Is there a different part number for GD engines? Anyone know?

I am rebuilding one of my V2's and am using thee SC7400's in it, with Manley
14024 rods.

Hey Marnix, while I have your ear, I bought yet another V2 STi engine a few weeks ago. I think it is an RA variant due to the 5th injector.

Anyway, I took a head off it to have a look and the head gasket is one of those 2 layer steel hobbies. Not seen that before. And the lifters are shim under bucket. Just thought I would let you know as I know you're interested in such things.

Cheers guys
renhoek is offline   Reply With Quote
Old 07-08-2012, 10:52 AM   #7
Marnix
Scooby Specialist
 
Member#: 51480
Join Date: Dec 2003
Chapter/Region: International
Location: The Netherlands
Vehicle:
1984 AM5, 1994 BC4,
2010 BR5

Default

It doesn't matter what EJ20 piston you use as long as you match gasket thickness to compression height of the piston. Ideally you want to end up with 1.1 mm squish for a high revving engine or even 2.3 mm as per 2001 and on JDM EJ207 STI.
Marnix is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 06:31 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.