03 wrx rebuild questions

Josebugeye · 05-06-2013, 10:56 AM

Hello everyone so I am going to be attempting to do a rebuild soon on my ej205 although I have a lot of questions un answered. I am going to rebuild because I had done a leakdown test and found I was leaking 20% +/- on 3 of my cylinders . I have talked to my tuner about reaching 300whp and having a reliable daily. The car is currently at 104k miles and has a stage 2 open source tune with a Megan catless downpipe, Cobb rep cat back and intake. I have never done an engine rebuild before although I do all my mechanical work my self so I'm intermediate with my mechanical skills and wanted to tackle on my first rebuild. Although before I do so I have several questions I think someone might be able to answer .

So I plan on getting ACL bearings although when I look for them on rallysportdirect they offer 2 standard sizes a position 5 and position 3. How would I determine this before I buy? I've seen several threads on bearings but haven't had luck on how to determine which I should buy. As well as what would be my benefit of getting the ACL race bearings to the regular ACL bearings since I am looking to be more reliable.

My next question is on the machine work. I have heard some of my co workers say that if I get my block honed to get a fresher cylinder wall I have to let the shop that's doing it basically assemble the block for me since they would have to test that everything is working in correct order, although what I wanted was to get my block and head machined and then I wanted to assemble it all together (pistons, rods, bearings and such) so that I can learn how to do so.

Last but not least what do you guys think about used parts in a rebuild.? I wanted to have forged rods ( STi rods, ej207 rods or manley rods) since I want to support my power goal. Although I have read you will have to get them rebalanced. As well should I get new wrx stock pistons? That was my first intention although now I'm in a dilemma to get cp pistons although they are a bit out of my budget I can wait and save up for them .

Let me know what you guys think! Thanks in advanced !!

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Josebugeye · 05-07-2013, 08:40 AM

Morning I need some help !

allfours · 05-07-2013, 12:52 PM

If this is your only car. This is a very bad idea. Subarus are very picky. I would not recomend rebuding it unless its a project car. Get an oem sti bottom end and have your heads machined to match. Much easier and SHOULD be more reliable.

Josebugeye · 05-07-2013, 04:02 PM

It's not my only car. Although why is it bad its just a mild build if anything .

Bamofo · 05-07-2013, 05:49 PM

There are tons of people that come on asking the same thing and stickies that answer all your questions. I agree with everyone else and say subaru is not the first motor you want to build.... Dsm, maybe... But not the subaru.. It's miserable and sometimes you do it all right and it still doesn't run properly because of something you didn't even know existed.

with that said I'm not that big of an ass... So my advise would be to tear it down to the shortblock yourself. And then you can clean the heads, check for leaks, and still get the satisfaction that you worked on it... Have someone else build the block and pack the oil pump for you so it primes properly. That way you only have to deal with heads, valve clearances, timing belt, covers and accessories. Believe it or not your first time that stuff will take for ever.

PM me if you have any specific questions.

Josebugeye · 05-07-2013, 10:41 PM

Right on I see what you mean. I have read that built motors tend to have more problems as well, that's why I tried to keep it at a stock bore and just get forged rods. Thanks bamofo I will definately shoot you a pm when I need I get stuck .

05-06-2013, 10:56 AM	#1
Josebugeye Scooby Newbie Member#: 310906 Join Date: Feb 2012 Location: Sacramento, CA Vehicle: 2003 WRX	Hello everyone so I am going to be attempting to do a rebuild soon on my ej205 although I have a lot of questions un answered. I am going to rebuild because I had done a leakdown test and found I was leaking 20% +/- on 3 of my cylinders . I have talked to my tuner about reaching 300whp and having a reliable daily. The car is currently at 104k miles and has a stage 2 open source tune with a Megan catless downpipe, Cobb rep cat back and intake. I have never done an engine rebuild before although I do all my mechanical work my self so I'm intermediate with my mechanical skills and wanted to tackle on my first rebuild. Although before I do so I have several questions I think someone might be able to answer . So I plan on getting ACL bearings although when I look for them on rallysportdirect they offer 2 standard sizes a position 5 and position 3. How would I determine this before I buy? I've seen several threads on bearings but haven't had luck on how to determine which I should buy. As well as what would be my benefit of getting the ACL race bearings to the regular ACL bearings since I am looking to be more reliable. My next question is on the machine work. I have heard some of my co workers say that if I get my block honed to get a fresher cylinder wall I have to let the shop that's doing it basically assemble the block for me since they would have to test that everything is working in correct order, although what I wanted was to get my block and head machined and then I wanted to assemble it all together (pistons, rods, bearings and such) so that I can learn how to do so. Last but not least what do you guys think about used parts in a rebuild.? I wanted to have forged rods ( STi rods, ej207 rods or manley rods) since I want to support my power goal. Although I have read you will have to get them rebalanced. As well should I get new wrx stock pistons? That was my first intention although now I'm in a dilemma to get cp pistons although they are a bit out of my budget I can wait and save up for them . Let me know what you guys think! Thanks in advanced !! * Registered users of the site do not see these ads. Last edited by Josebugeye; 05-06-2013 at 11:01 AM.

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05-07-2013, 08:40 AM	#2
Josebugeye Scooby Newbie Member#: 310906 Join Date: Feb 2012 Location: Sacramento, CA Vehicle: 2003 WRX	Morning I need some help !

05-07-2013, 12:52 PM	#3
allfours Scooby Newbie Member#: 339966 Join Date: Dec 2012 Chapter/Region: NESIC Location: Connecticut Vehicle: 05 WRX CGM	If this is your only car. This is a very bad idea. Subarus are very picky. I would not recomend rebuding it unless its a project car. Get an oem sti bottom end and have your heads machined to match. Much easier and SHOULD be more reliable.

05-07-2013, 04:02 PM	#4
Josebugeye Scooby Newbie Member#: 310906 Join Date: Feb 2012 Location: Sacramento, CA Vehicle: 2003 WRX	It's not my only car. Although why is it bad its just a mild build if anything .

05-07-2013, 05:49 PM	#5
Bamofo Scooby Specialist Member#: 159743 Join Date: Sep 2007 Location: Plymouth Ma Vehicle: 07 STI Limited TurboMike Tuned 2.35	There are tons of people that come on asking the same thing and stickies that answer all your questions. I agree with everyone else and say subaru is not the first motor you want to build.... Dsm, maybe... But not the subaru.. It's miserable and sometimes you do it all right and it still doesn't run properly because of something you didn't even know existed. with that said I'm not that big of an ass... So my advise would be to tear it down to the shortblock yourself. And then you can clean the heads, check for leaks, and still get the satisfaction that you worked on it... Have someone else build the block and pack the oil pump for you so it primes properly. That way you only have to deal with heads, valve clearances, timing belt, covers and accessories. Believe it or not your first time that stuff will take for ever. PM me if you have any specific questions.

05-07-2013, 10:41 PM	#6
Josebugeye Scooby Newbie Member#: 310906 Join Date: Feb 2012 Location: Sacramento, CA Vehicle: 2003 WRX	Right on I see what you mean. I have read that built motors tend to have more problems as well, that's why I tried to keep it at a stock bore and just get forged rods. Thanks bamofo I will definately shoot you a pm when I need I get stuck .