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Old 08-20-2019, 03:23 AM   #1
StarkWRX
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Default Quality valves for a reliable built engine? (~350whp)

OK everyone, I'm building my first engine and starting with the heads.

Current 2006 WRX has 160K miles, Stage 2 for the last 65K and started losing oil since 120K. Now I'm pushing coolant into the overflow tank and from what I've read it's a head gasket (also some minor bubbles).

So, I decided to start with the heads and ordered NEW BLANKS (W25) and plan on buying the short block from IAG/Crawford/etc.

RSD, IIR, MAP, etc. sell Supertech, GSC, Manley, BC, Ferrea, etc.

I read Manley are exactly 6mm in stem diameter, while Supertech and some others are 5.96-5.97mm so they don't require reaming the valve guides.

I also read a bunch of horror stories about valves dropping (Supertech and a few others).


My question for you experts is: What valve/valve guide/spring/retainer combo would you recommend for a modest 350-400whp setup where minimum adjustment/machining is needed?

I was thinking:

Intake: OEM valves/GSC guides with stoppers/Manley spring & retainer

Exhaust: Supertech Inconel/GSC guides with stoppers/Manley spring & retainer

Do the Supertech valves still drop?

Thanks!


UPDATE #1:
I measured a lightly used OEM intake valve stem and it is 5.96-5.97mm

Found out Manley Race Flo (PN 11138-8) is actually 5.97mm and NOT 6.00mm as it seems in other places. Maybe the thread I was reading (from 2012) is when they were actually 6mm? Or maybe a different part number? Who knows.




Bibliography:

https://forums.nasioc.com/forums/sho....php?t=2897571
https://forums.nasioc.com/forums/sho....php?t=1431376
https://forums.nasioc.com/forums/sho....php?t=1798862
https://forums.nasioc.com/forums/sho....php?t=2885937
https://forums.nasioc.com/forums/sho....php?t=2885583
https://forums.nasioc.com/forums/sho....php?t=2825985
https://forums.nasioc.com/forums/sho....php?t=2652586
https://forums.nasioc.com/forums/sho....php?t=2472022
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Last edited by StarkWRX; 08-23-2019 at 01:54 PM.
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Old 08-20-2019, 07:47 AM   #2
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Old 08-20-2019, 11:05 AM   #3
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If you are looking for 400whp just keep the heads stock. unless you just want to spend money. I run supertech everthing with +1 int/exh, 82lb springs, 282 cams. But in my opinion a stock head is awesome for 350-400 whp.
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Old 08-20-2019, 12:10 PM   #4
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Sti valves. Done.
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Old 08-23-2019, 08:38 AM   #5
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GSC valves, best quality I have come across, there all I use, Subaru's, GTR, Supra, 4g63 and Honda's, done 600+ heads now with them.
Stay away from Supertech ANYTHING, junk
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Old 08-23-2019, 09:42 AM   #6
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Thanks folks!

Stu, since I’m aiming for reliability I was thinking inconel exhaust would be better since I’m experimenting with E30-E85 and they can resist higher temps.

TDagen, aren’t they the same? The heads are obviously different but I couldn’t find a difference in the VALVES (INTAKE! I'm aware the exhaust have sodium).

CBRE I heard mixed feelings about Supertech. BTW I’m in Pittsburgh every weekend, have a house out by Natrona. Do you have a shop?

Last edited by StarkWRX; 08-23-2019 at 01:55 PM.
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Old 08-23-2019, 10:30 AM   #7
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If you are building for reliability then don't skimp out on the machining work. If you are replacing valve guides then they should always be reamed or honed to insure the stem to guide clearance is correct.

Also, when installing new guides you are changing the concentricity of the guide to the valve seat and it is highly (always) recommended to get a full valve job. Trying to lap the new valve to the old seat is not a good idea and will not end well. The only way to insure true concentricity is when cutting new seats. (The seat cutter has a centering pin that centers off the ID of the guide when it cuts the new seat.)
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Old 08-23-2019, 01:47 PM   #8
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Quote:
Originally Posted by vwown3d View Post
If you are building for reliability then don't skimp out on the machining work. If you are replacing valve guides then they should always be reamed or honed to insure the stem to guide clearance is correct.

Also, when installing new guides you are changing the concentricity of the guide to the valve seat and it is highly (always) recommended to get a full valve job. Trying to lap the new valve to the old seat is not a good idea and will not end well. The only way to insure true concentricity is when cutting new seats. (The seat cutter has a centering pin that centers off the ID of the guide when it cuts the new seat.)

Thanks! As stated above this is an entirely NEW head with new valves/guides/springs/etc.

I will outsource any machining necessary, but as I've noticed, if the valve is the correct spec (5.96-5.97mm intake) then the stem-to-guide clearance should be correct.

I will definitely use a gauge pin to check the guides.

Last edited by StarkWRX; 08-23-2019 at 01:56 PM.
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Old 08-23-2019, 05:09 PM   #9
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Manley valves, done I have 100k on mine
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Old 08-23-2019, 09:06 PM   #10
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[quote=Stay away from Supertech ANYTHING, junk[/QUOTE]

Lets see some prof. Ive had supertech in my heads since 2007 and never had a problem. Hardly junk!
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Old 08-23-2019, 11:09 PM   #11
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Quote:
Originally Posted by StarkWRX View Post
Thanks folks!

Stu, since Iím aiming for reliability I was thinking inconel exhaust would be better since Iím experimenting with E30-E85 and they can resist higher temps.

TDagen, arenít they the same? The heads are obviously different but I couldnít find a difference in the VALVES (INTAKE! I'm aware the exhaust have sodium).

CBRE I heard mixed feelings about Supertech. BTW Iím in Pittsburgh every weekend, have a house out by Natrona. Do you have a shop?
No body has pointed this out so just FYI; E85 burns cooler than gasoline, and thatís because itís around 85% (cool burning) alcohol. No need for a valve that resists higher temps for that application (E85). E85 actually helps engine parts last longer by burning cooler.

Correct the intakes are the same, and the sti exhaust are the sodium filled ones. Not cheap, but work excellent. The sti valves can take 350-400whp all day long, but if you want to get aftermarket stuff for a strong motor thatís legit too. More than one way to get it done

And by the way donít forget about gsc for valvetrain. Very high quality.
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Old 08-23-2019, 11:13 PM   #12
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OEM valves are said to be good for up to 400hp. Save yourself the coin and use it for other upgrades IMO.

Last edited by JDMJNKY; 08-23-2019 at 11:14 PM. Reason: ninja edit corrected 500 to 400 per Td
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Old 08-24-2019, 02:11 PM   #13
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TDagen, correct, E85 in fact burn a lot cooler, but I’m not on E85 yet. I’m making my own blends and experimenting. Maybe inconel is overkill but I’ve been leaning out my AFRs and want that extra cushion of safety. Does that make sense?

JDMJNKY the dealer quoted me $17 for the intake and $75 for the sti exhaust. That’s $136 for the intake and $600 for the exhaust total. Yeah Subaru makes some quality things but it’s not worth it. You can get better stuff for less.
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Old 08-24-2019, 03:54 PM   #14
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Quote:
Originally Posted by StarkWRX View Post
TDagen, correct, E85 in fact burn a lot cooler, but Iím not on E85 yet. Iím making my own blends and experimenting. Maybe inconel is overkill but Iíve been leaning out my AFRs and want that extra cushion of safety. Does that make sense?
Any Ethanol you add to gasoline will cool the combustion event, if properly tuned (air fuel ratios). Are you adjusting the tune at all?

Fuel in general (gasoline, E85, race gas) cools the combustion event so the more fuel you pull out the hotter it will get.

If you have access to E85 why not get a set of injectors and tune it for E85/flex fuel? Just saying since your putting big money into the motor. I estimate those heads will be about 4-5k by themselves, kind of expensive to experiment with.
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Old 08-25-2019, 02:32 AM   #15
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Quote:
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JDMJNKY the dealer quoted me $17 for the intake and $75 for the sti exhaust. Thatís $136 for the intake and $600 for the exhaust total. Yeah Subaru makes some quality things but itís not worth it. You can get better stuff for less.
Send it. Aftermarket valves here we come lol
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Old 08-25-2019, 04:06 PM   #16
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Quote:
Originally Posted by TDagen View Post
Any Ethanol you add to gasoline will cool the combustion event, if properly tuned (air fuel ratios). Are you adjusting the tune at all?

Fuel in general (gasoline, E85, race gas) cools the combustion event so the more fuel you pull out the hotter it will get.

If you have access to E85 why not get a set of injectors and tune it for E85/flex fuel? Just saying since your putting big money into the motor. I estimate those heads will be about 4-5k by themselves, kind of expensive to experiment with.
Correct. I have access to E85 but not injectors on the old engine that Iím currently runningójust stock. Iíve been following the E85 FAQ and so far on E30, 15psi TD04 with stock injectors I get about 75% IDC around 5500 rpm which suggests I could do more ethanol and still be safe (AFR 11.6 gasoline)

Yes I tune (roughly, no dyno) each time I increase the mix with ethanol.

I donít plan on experimenting with the new heads Iím building. Iím experimenting with the old ones.

The new engine is getting 1000-1200 cc injectors and a flex fuel kit.
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Old 08-25-2019, 10:57 PM   #17
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If your having fun now blending, you will have a lot of fun with the bigger injectors and e85. Road tuning with romraider (or whatever) is also a blast (imo). Have fun!

One more shout out for the gsc if your going aftermarket. A Subaru cylinder head expert recommended I do all gsc valves and beehive springs and retainers on my 600+ build.
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Old 08-26-2019, 08:49 AM   #18
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Thank you everyone for your input it’s much appreciated!

I’ve settled for Manley intake valves for $160 and GSC superalloy exhaust valves for $200. They might not be inconel but still rated at 2000F.

I also want a Manley sticker on my build, haha.


When I pull the old engine out and rebuild the heads I’ll probably go with Supertech and use that engine as an experiment. Then I can report back and let you know if I have a $5000 paperweight lol


If you guys are ever in Morgantown or Pittsburgh, first beer on me.
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Old 08-26-2019, 09:02 AM   #19
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Quote:
Originally Posted by TDagen View Post
If your having fun now blending, you will have a lot of fun with the bigger injectors and e85. Road tuning with romraider (or whatever) is also a blast (imo). Have fun!

One more shout out for the gsc if your going aftermarket. A Subaru cylinder head expert recommended I do all gsc valves and beehive springs and retainers on my 600+ build.



So jealous of the 600+

Iíll probably do that after Iíve mastered the 400. Baby steps.
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Old 08-26-2019, 11:42 PM   #20
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Lets see some prof. Ive had supertech in my heads since 2007 and never had a problem. Hardly junk!
I have plenty

https://forums.nasioc.com/forums/sho....php?t=2828029
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Old 08-27-2019, 11:29 AM   #21
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User1029, I see you have an IAG. Is it just the short block or long? When did you get it and what internals did they use?
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Old 08-29-2019, 07:12 PM   #22
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Old 08-31-2019, 02:54 AM   #23
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^^^ so the company that built the engine put blame on something/someone else^^^
that's unheard of...
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Old 09-01-2019, 06:53 PM   #24
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^^^ so the company that built the engine put blame on something/someone else^^^
that's unheard of...
surprisedcat.gif

https://www.iwsti.com/forums/gd-members-journals/163015-07evok1lr-big-update-600-whp-topspeed-ftw-78.html?highlight=Supertech#post3781226

Iíll dig up jays thread if needed
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Old 09-02-2019, 06:08 PM   #25
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^^^Wow another compelling story of them just snapping off^^^. Like I said, I do all my own work and have been running them at 8k+ and 42 psi for years and before that I was at 32 with them.They work great and Ill belive in my proof before I believe some keyboard jockey who doesent do his on work.
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