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Old 11-12-2022, 11:27 AM   #1
4eat05
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Default Head rebuild questions.

I will soon be sending off my 2005 Wrx ej205 non avcs heads to be cleaned, milled, refreshed and had some questions I would like some opinions in.

I'm kind of going for a stockish, oem+ish rebuild. I don't really plan on any heavy porting or aftermarket cams. Definitely replacing valve stem seals and likely bronze valve guides and new oem buckets to set lash.

If doing just a light port and polish, and using oem ej205 cams, is there any benefit to aftermarket valve springs? Or just buy new oem valve springs? Oem sti valve springs? I don't plan on reusing my old springs, which is why I'm interested in aftermarket or new oem.

If using oem springs, is there any benefit to aftermarket retainers and/or keepers? Lighter/stronger sounds good to me. What about aftermarket spring seats? I don't plan on reusing the old stuff, so interested in aftermarket or new oem.

Would there be any benefits to stock diameter aftermarket stainless valves? Stronger, better flowing sounds good to me, or should I just stick with new oem valves?

I don't plan on doing anything crazy, but don't plan on reusing most of my old stuff. So its either new oem pieces or a slight upgrade.

Any advice or recommendations would be greatly appreciated.
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Old 11-12-2022, 12:20 PM   #2
benflynn
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I always use bc1600 springs in my stock cam heads. They are a good price and give you some head room
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Old 11-13-2022, 07:02 PM   #3
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if using oem cams there is no benefit as there will be o binding, you can even use a 262 grind with a mild lift... stage one cam and you should be okay, unless you want to bump up the red line. I hve used stock on a 400hp 2.1 with v9 heads and avcs running red line to 8000
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Old 11-14-2022, 12:17 PM   #4
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Quote:
Originally Posted by subaru_gc8 View Post
if using oem cams there is no benefit as there will be o binding, you can even use a 262 grind with a mild lift... stage one cam and you should be okay, unless you want to bump up the red line. I hve used stock on a 400hp 2.1 with v9 heads and avcs running red line to 8000
No plans on running aftermarket cams or raising redline past 7k. So just stick to oem springs?
Any benefit to titanium retainers?
Stock size stainless valves?
Or just stick to stock pieces and new valve stem seals?
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Old 11-14-2022, 12:34 PM   #5
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i'd say all stock except get a good set of springs and matching titanium retainers. if was me i'd call IAG and ask them for springs/retainers they would recommend.

maybe this: https://www.iagperformance.com/iag-s...aru-ej-engine/ $249

if they have any black friday discount maybe they let you get the discount today!

i dont think i would re-use the stock springs you already have, probably are tired out a little bit depending on the miles on them. not worth the risk
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Old 11-14-2022, 12:35 PM   #6
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double posted bug
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Old 11-15-2022, 02:01 PM   #7
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Quote:
Originally Posted by SchoobieDoobie View Post
i'd say all stock except get a good set of springs and matching titanium retainers. if was me i'd call IAG and ask them for springs/retainers they would recommend.

maybe this: https://www.iagperformance.com/iag-s...aru-ej-engine/ $249

if they have any black friday discount maybe they let you get the discount today!

i dont think i would re-use the stock springs you already have, probably are tired out a little bit depending on the miles on them. not worth the risk
Recommend those with stock cams and factory 7k rpm redline?
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Old 11-24-2022, 11:38 PM   #8
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Not really. To stiff and you'll get spring bounce. Also the stiff spring will slam the valve into the seat. If You have the seats cut then you'll want to adjust and get a stiffer spring to retain seat pressure and avoid valve float.
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Old 11-28-2022, 02:26 PM   #9
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Always new springs. Do you run it hard? Rev the **** out of it compared to your expected normal driver? I do, so I always use some sort of better spring. If it were a vortech or LS I’d use at least blue z06/Chevy perf springs and no word on all those C5 z06 beating the seats out.

Let’s not forget about boost, any added boost is pushing against that closed valve.
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Old 11-28-2022, 02:55 PM   #10
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Quote:
Originally Posted by benflynn View Post
Always new springs.

Let’s not forget about boost, any added boost is pushing against that closed valve.

bingo!
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Old 11-28-2022, 03:21 PM   #11
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Figured id mention this tomei sells shims also. So you can shim the factory or sti valve springs. I got the shims on my car and had good luck with them. Sometimes the springs and whatnot arent equal seat pressures. They can vary depending on seat depth and valve seat. If its slightly worn or machined. A small shim here and there can equal it out. Like setting a bearing clearance pretty much. Or if You just want more seat pressure. They make all different sizes. From. Example .001" to .010"

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Old 11-30-2022, 04:47 PM   #12
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well..... no porting really needed. Freshen the head and new springs... that's plenty. Stock heads will work fine to near 500hp no problem.

You got a baby turbo or what?
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Old 12-01-2022, 06:09 AM   #13
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Quote:
Originally Posted by FuJi K View Post
well..... no porting really needed. Freshen the head and new springs... that's plenty. Stock heads will work fine to near 500hp no problem.



You got a baby turbo or what?
Someone made 700whp on stock heads forgot who it was. He had a silver gdb. Cams springs big turbo.

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Old 12-02-2022, 09:44 PM   #14
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Quote:
Originally Posted by FuJi K View Post
well..... no porting really needed. Freshen the head and new springs... that's plenty. Stock heads will work fine to near 500hp no problem.

You got a baby turbo or what?
Vf34 with full boltons/supporting mods
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Old 12-02-2022, 11:06 PM   #15
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Yha, if your not planning on upgrading that turbo and trying for big power where early spool is critical for you, leave the head alone and just replace all moving parts with oem, aftermarket if you have the extra cash. Copper valve guides are a good idea if yours are worn out and planning on keeping the car for a while.

Last edited by BlackFighter; 12-02-2022 at 11:17 PM.
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Old 12-08-2022, 02:40 AM   #16
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Originally Posted by 4eat05 View Post
Vf34 with full boltons/supporting mods
Baby turbo.... keep it simple.

Do What BlackFighter said.
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Old 12-08-2022, 06:30 AM   #17
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I like to run better valves (OEM size), because they stay round a true much longer than OEM, especially above OEM power levels. Performance springs on anything running higher than boost/flow, but usually I just run a smaller step up in spring pressure, unless it's a big power build.

Can you do this on stock heads? Sure. Will it perform and last as long? Not with how I drive :P
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Old 12-08-2022, 06:40 AM   #18
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Quote:
Originally Posted by KillerBMotorsport View Post
I like to run better valves (OEM size), because they stay round a true much longer than OEM, especially above OEM power levels. Performance springs on anything running higher than boost/flow, but usually I just run a smaller step up in spring pressure, unless it's a big power build.

Can you do this on stock heads? Sure. Will it perform and last as long? Not with how I drive :P
Could you expand upon why you do not like to run oversized valves?

Thanks!
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Old 12-20-2022, 04:02 PM   #19
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Quote:
Originally Posted by 4eat05 View Post
No plans on running aftermarket cams or raising redline past 7k. So just stick to oem springs?
Any benefit to titanium retainers?
Stock size stainless valves?
Or just stick to stock pieces and new valve stem seals?
well i believe there really is no issues with the stock springs, but if you want to one day up the rev limit I think its better to over build a bit for strength sake.
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Old 12-23-2022, 01:56 PM   #20
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Quote:
Originally Posted by KillerBMotorsport View Post
I like to run better valves (OEM size), because they stay round a true much longer than OEM, especially above OEM power levels. Performance springs on anything running higher than boost/flow, but usually I just run a smaller step up in spring pressure, unless it's a big power build.

Can you do this on stock heads? Sure. Will it perform and last as long? Not with how I drive :P
what valves do you like/dislike?
what springs do you like/dislike for small builds?
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Old 12-23-2022, 05:00 PM   #21
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Quote:
Originally Posted by K3rm1tth3fr0g View Post
Could you expand upon why you do not like to run oversized valves?
The seats get too small. To do it properly new seats need to be installed into the heads, which no one does. The bang-for-the-buck just isn't there. Just my 2 cents.


Quote:
Originally Posted by kakarot09 View Post
what valves do you like/dislike?
what springs do you like/dislike for small builds?
I used to prefer Ferrea but have really liked GSC stuff more recently. I'd have to look up the springs, but we use the same brand when building the heads.
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Old 10-13-2023, 10:38 AM   #22
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Quote:
Originally Posted by subaru_gc8 View Post
well i believe there really is no issues with the stock springs, but if you want to one day up the rev limit I think its better to over build a bit for strength sake.
If you got aftermarket cams you need to check your lift and see what the coil bind is. Because if the lift is higher then stock the spring will touch coils and bind. A stage 1 cam might work ok but a stage 2 cam might bind and deform a spring especially if you add the extra tomei springs like i run when building my heads.

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Old 10-13-2023, 10:54 AM   #23
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Quote:
Originally Posted by spoolinsti05 View Post
If you got aftermarket cams you need to check your lift and see what the coil bind is. Because if the lift is higher then stock the spring will touch coils and bind. A stage 1 cam might work ok but a stage 2 cam might bind and deform a spring especially if you add the extra tomei spring shims like i run when building my heads.

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Old 10-13-2023, 11:58 AM   #24
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Quote:
Originally Posted by spoolinsti05 View Post
a stage 2 cam might bind and deform a spring
springs don't deform when they go solid, they blow up the lifter/cam
that's why it's called going solid
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Old 10-25-2023, 09:20 AM   #25
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Originally Posted by rtv900 View Post
springs don't deform when they go solid, they blow up the lifter/cam

that's why it's called going solid
Another scenario. Then the valve goes into the chamber. Ouch.

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