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Old 10-19-2011, 11:42 PM   #1
theonlygreat
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Default EJ20G HLA Performance Valve Springs

After doing lots of measuring and internet searching, I have found that Eibach makes a valve spring that might work for the EJ20G with HLA's, part #20438.01.

Stock Specs (spring pressures taken from 96 EJ25D specs in FSM, may or may not be identical)
Installed height: 1.220"
Seat Pressure: 59lbs
Open height: .913
Open Pressure: 119lbs
Outside Diameter: 1.040"
Minimum Inside Diameter: .726" (measured at spring seat washer thing)
Solid/Bind Height: .867" (measured in vice)

Eibach 20438.01 Specs

Installed height: 1.260"
Seat Pressure: 60lbs
Open Height: .790"
Open Pressure: 172lbs
Outside Diameter: 1.080"
Inside Diameter: .790"
Solid/Bind Height: .730"
Max Lift: .470"

The pressures I calculated with these springs on an EJ20G
Seat Pressure: 69lbs
Open Pressure: 142lbs (stock lift)
Max Pressure/Lift: 172lbs @ .450"(reduced lift due to slightly shorter installed height)

Pressures of other springs for newer WRX/STI
Supertech: Seat-64lbs Open-199lbs@.450"
Brian Cower: Seat-60lbs Open-160lbs@.420"
Manley: Seat-60lbs Open-151lbs@.370"(Stock) 187lbs@.525"(max)
Manley (Race?): Seat-95lbs Open-257lbs@.490"

Any questions or comments are welcome. I am no expert on the subject, but I will probably be ordering these springs to give me more reliable power around or above 7000rpm with EJ20K cams. The seat pressure is a touch higher, but aside from custom springs or different heads, it is the only option I have found. The outside diameter is .040" larger, I will have to check my measurements and see if i measured the spring or the retainer for OD. Is there anybody that thinks .040" (1mm total or .5mm on each side) would be too much to stick out from the retainer? I know it would still fit under the HLA.

Side note, does anybody know how much can be ground from the cams before you reach the lash limit of the HLA?
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Old 10-28-2011, 09:15 PM   #2
theonlygreat
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A little update on this. The HLA buckets are like 1.0886" ID, so the springs above would be a pretty tight fit. Looking at the underside of them, you can see where the stock springs have made some light contact so I would not recommend running the larger springs. After my long search, the short installed height of the HLA valve springs have proven to be difficult. The stock ones bottom out at 0.353" lift, which is not that great seeing that it is less than a newer stock STI . I have decided to got with EJ20K/late EJ20G heads with the shim over bucket style. If anyone is interested, I have found that Eibach valve springs for a Ford 4.6L in a Mustang or F150 fit perfectly. They are part number 25409.1 or 25409.116 for a set of 16. These can be had for about $10 per spring, which was cheaper than anything I could find for the EJ20K/EJ25D heads. They have the following specs:

Eibach 25409.1 Specs
Installed height: 1.570"
Seat Pressure: 84lbs
Open Height: 1.020"
Open Pressure: 202lbs
Outside Diameter: 1.040"
Inside Diameter: .740"
Solid/Bind Height: .950"
Max Lift: .550"

I don't have the specs in front of me, but the EJ20K installed height is like 1.640", which would change the seat pressure to about 69lbs and give you a max lift of 0.620" @ 202lbs if you wanted to get crazy with it (I am not sure what lift it would bottom out on the valve stem seal, these numbers are just what the spring is capable of). Open pressure is about 137lbs at stock lift of 0.319". The Eibach spring is slightly conical (the 1.040" OD is the wide end at the bottom) and tapers to fit the EJ20K retainer with a snug click around the inner step, the machine shop said that close fit would not be a problem. With all the extra room this spring has, you could shim it for more pressure if you really wanted to.

Last edited by theonlygreat; 10-29-2011 at 01:38 PM. Reason: corrected measurement typo
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Old 10-29-2011, 01:41 AM   #3
Marnix
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If the installed height is almost half an inch lower on the EJ20G/K then the seat pressure is higher, not lower. Too much pressure will increase wear on cam lobes and shims (they could break).

What are your plans, what boost and rpm do you intend to run? If you want to run 10% more rpms then you have to increase valve spring pressure by approximately 33%.
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Old 10-29-2011, 01:37 PM   #4
theonlygreat
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Whoops, that was a typo. Installed height on the shim over bucket should be 1.640", I will edit the post.
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Old 11-10-2011, 01:51 PM   #5
gf8love
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You seem to know alot about the valvetrain or have done a lot of research. I ran into some problems with my version 4 ej20g and ended up having to replace all four intake valves on one head. The machine shop installed 02 wrx valves and said they would work but when I went to install it all back together the shim that it wanted was 3.28 mm (subaru dosent make/ too large). Ended up finding out the buckets that worked with the old valves do not work with the 02 wrx valves, so my question is do you know what valves will get me back into spec?
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Old 11-10-2011, 01:57 PM   #6
Marnix
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USDM EJ25D valves (1997-1998). The 02 WRX valves are too short.
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Old 11-10-2011, 02:16 PM   #7
gf8love
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Quote:
Originally Posted by Marnix View Post
USDM EJ25D valves (1997-1998). The 02 WRX valves are too short.
the only problem is that the machine shop already installed the valves and dosent want to take the valves back out....I was told that i could just get the appropriate lifters/buckets to make it work..I am just wondering if anyone knows which lifter/buckets will work?
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Old 11-10-2011, 08:53 PM   #8
theonlygreat
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I don't believe any of the bucket styles are going to get you the thickness that you need. The newer WRX camshaft has a larger diameter and that is why the valves are a little shorter. The most practical/appropriate/proper solution is putting in EJ25D valves, they are an exact fit and widely available. Otherwise you need to have some material added onto the tips of the valves to make them taller, which would probably require taking them out anyway. The shorter valves with an installed height of 1.420" is also taking up a lot of the spring before it bottoms out. That's like having cams that are an extra .220" lift over stock. That is a lot on a stock spring, I would be surprised if they didn't bottom out or just break. Unfortunately I don't have the coil bind height accessible right now or I could say for sure whether they would bottom out or not.

Last edited by theonlygreat; 11-10-2011 at 08:59 PM.
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Old 11-12-2011, 01:25 PM   #9
gf8love
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Quote:
Originally Posted by theonlygreat
I don't believe any of the bucket styles are going to get you the thickness that you need. The newer WRX camshaft has a larger diameter and that is why the valves are a little shorter. The most practical/appropriate/proper solution is putting in EJ25D valves, they are an exact fit and widely available. Otherwise you need to have some material added onto the tips of the valves to make them taller, which would probably require taking them out anyway. The shorter valves with an installed height of 1.420" is also taking up a lot of the spring before it bottoms out. That's like having cams that are an extra .220" lift over stock. That is a lot on a stock spring, I would be surprised if they didn't bottom out or just break. Unfortunately I don't have the coil bind height accessible right now or I could say for sure whether they would bottom out or not.
okay I had some ej25d valves ordered in went to install them and they are way to long...any suggestions?
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Old 11-12-2011, 02:47 PM   #10
theonlygreat
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What shim/bucket type do you have? Are the valves for the 97-98 EJ25D? Like in the Legacy Outback/Impreza 2.5RS? Perhaps you ended up with EJ251 vavles.
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Old 11-12-2011, 06:26 PM   #11
gf8love
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Quote:
Originally Posted by theonlygreat
What shim/bucket type do you have? Are the valves for the 97-98 EJ25D? Like in the Legacy Outback/Impreza 2.5RS? Perhaps you ended up with EJ251 vavles.
Yeah I did end up with the ej251. The parts store messed up.
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