Stock valve springs: New one to me! Help verify!!
03-12-2007, 08:13 AM
#1
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Stock valve springs: New one to me! Help verify!!
Getting into putting my VG30ET back together again. Ordered dual spring set from Schneider Cams with added pressure to protect against valve float.
During the original build, I had put new springs in the heads. Having recently pulled them again and looking, I noticed they were dual springs. I double checked my old stock heads, they are dual springs too! Then I checked the stock JDM (euro cams) turbo springs, they are single springs. What gives?
Did the newer VG's come with dual valve springs from the factory? Or is it a US spec difference? I originally bought my car stock, I doubt anyone put performance valve springs in the car. And I didn't ask the machine shop to install performance springs in the heads when originally rebuilt. Any clarity is appreciated.
During the original build, I had put new springs in the heads. Having recently pulled them again and looking, I noticed they were dual springs. I double checked my old stock heads, they are dual springs too! Then I checked the stock JDM (euro cams) turbo springs, they are single springs. What gives?
Did the newer VG's come with dual valve springs from the factory? Or is it a US spec difference? I originally bought my car stock, I doubt anyone put performance valve springs in the car. And I didn't ask the machine shop to install performance springs in the heads when originally rebuilt. Any clarity is appreciated.
03-21-2007, 08:27 PM
#6
Im almost sure all vgs had dual springs. I know my 89 and 91 do. The FSM show no diagram of a VG with single springs. The z31 apparently had dual springs too, because JWT sells replacement outer springs and says you dont need the inner springs. (They dont sell inner springs.)
So your JDM VG must have either been upgraded with JWT springs, or JDM engines only had a single spring to begin with
So your JDM VG must have either been upgraded with JWT springs, or JDM engines only had a single spring to begin with
03-23-2007, 06:08 PM
#8
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I confirmed that JWT does sell only the outer spring. However, I also confirmed what I recalled in that they state only the outer/single spring is needed...."does not use inner spring."
Again, knowing this previously (as I did some talking with Schneider before the purchase of the spring kit, comparing it to JWT), I assumed that performance springs were typically dual spring. Schneider stated that there were unaware of a single performance valve spring as being normally used in performance applications but could not specifically comment on JWT's work. Neither could he speak to the standard use of single versus dual spring in the stock setup.
Haven't referenced my FSM for the VG30 yet or looked at my VE. However, The FSM for the VG30DETT ('90) shows it as single spring. The Chilton's shows the VG30E as a dual spring versus showing the VE as a single spring.
Whether VG30E (US or JDM) have single or dual springs, I ask the question of what the difference between the two are? I would imagine the double have a greater capacity to remain square, stand up to higher rpms, and are more durable/wear less than single springs. Valve springs are a forgotten and disregarded part of our engines I have found.
Again, knowing this previously (as I did some talking with Schneider before the purchase of the spring kit, comparing it to JWT), I assumed that performance springs were typically dual spring. Schneider stated that there were unaware of a single performance valve spring as being normally used in performance applications but could not specifically comment on JWT's work. Neither could he speak to the standard use of single versus dual spring in the stock setup.
Haven't referenced my FSM for the VG30 yet or looked at my VE. However, The FSM for the VG30DETT ('90) shows it as single spring. The Chilton's shows the VG30E as a dual spring versus showing the VE as a single spring.
Whether VG30E (US or JDM) have single or dual springs, I ask the question of what the difference between the two are? I would imagine the double have a greater capacity to remain square, stand up to higher rpms, and are more durable/wear less than single springs. Valve springs are a forgotten and disregarded part of our engines I have found.
03-23-2007, 06:28 PM
#10
Originally Posted by MyGreenMax94
Two is always better than one?
but won't having stuper-stiff valve spring packs hurt power on the low end, since your engine will need to use more power to run the cams?
03-24-2007, 06:45 AM
#12
Just basing off of how springs work, having a dual spring setup would give you quite a bit of pressure. You could likely make a single spring have equal or more pressure than a single by changing the design of the spring itself so that could be what JWT is doing. I've always been under the impression that the JWT springs were upgrades so they must make the pressure a little higher with them. Might send them an email and ask about that.
I have my JDM VG-T out of the car and will be pulling the heads off so I'll check how the valve springs are setup in it. That would be quite interesting if the JDM version (or whichever version that use the euro cams) use a single spring setup instead. If they do, I might have to test them out and see what kind of pressure they put out and such.
I have my JDM VG-T out of the car and will be pulling the heads off so I'll check how the valve springs are setup in it. That would be quite interesting if the JDM version (or whichever version that use the euro cams) use a single spring setup instead. If they do, I might have to test them out and see what kind of pressure they put out and such.
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