Valve springs for boosted LSX ?
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Valve springs for boosted LSX ? 427 LSX pushing 20 psi, 9.0:1 static comp. Morel hydraulic roller lifters, Crower shaft mount rockers(steel, 1.8) Measured valve lift is .630/.640. ETP LS7/LSX heads were equiped with 150/420lb dual springs according to the build specs. Shifting at 6500 rpm. What kind of spring pressures should I be looking at for the rebuild?
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Street and strip truck as per my sig vid . Shift is set at 6500 but it does hit 7000.
If I stay with the current lift, I think I may need to go to the 2.0 installed height as shown for the 1530s (current setup measures 1.8") - A bunch of my valve seals were totally destroyed. The increased open pressure may also help with that.
Wouldn't say my valvetrain is lightweight. PAC says that the small diameter of the 1530s is for lightweight valve trains - how does this relate to spring diameter? What retainers and seats do these use? catalog shows N/A
Any advantages re duals/singles?
If I stay with the current lift, I think I may need to go to the 2.0 installed height as shown for the 1530s (current setup measures 1.8") - A bunch of my valve seals were totally destroyed. The increased open pressure may also help with that.
Wouldn't say my valvetrain is lightweight. PAC says that the small diameter of the 1530s is for lightweight valve trains - how does this relate to spring diameter? What retainers and seats do these use? catalog shows N/A
Any advantages re duals/singles?
Looks like something was not set up correctly really.
We have an entire package with the 1521 or you can step up to the Manley spring.
Either the 221435 or the 221436 would work for you. On those heads though, you should be able to run a larger spring. There are so many available that are over 1.3 OD.
Let me know and I can get you set up with a kit that will not leave you worrying. Both of those springs I quoted are close to what you had as far as pressures. The 221435 has some more seat and open pressure as well.
We have an entire package with the 1521 or you can step up to the Manley spring.
Either the 221435 or the 221436 would work for you. On those heads though, you should be able to run a larger spring. There are so many available that are over 1.3 OD.
Let me know and I can get you set up with a kit that will not leave you worrying. Both of those springs I quoted are close to what you had as far as pressures. The 221435 has some more seat and open pressure as well.
Street and strip truck as per my sig vid . Shift is set at 6500 but it does hit 7000.
If I stay with the current lift, I think I may need to go to the 2.0 installed height as shown for the 1530s (current setup measures 1.8") - A bunch of my valve seals were totally destroyed. The increased open pressure may also help with that.
Wouldn't say my valvetrain is lightweight. PAC says that the small diameter of the 1530s is for lightweight valve trains - how does this relate to spring diameter? What retainers and seats do these use? catalog shows N/A
Any advantages re duals/singles?
If I stay with the current lift, I think I may need to go to the 2.0 installed height as shown for the 1530s (current setup measures 1.8") - A bunch of my valve seals were totally destroyed. The increased open pressure may also help with that.
Wouldn't say my valvetrain is lightweight. PAC says that the small diameter of the 1530s is for lightweight valve trains - how does this relate to spring diameter? What retainers and seats do these use? catalog shows N/A
Any advantages re duals/singles?
As far as the 1521 is concerend i am affraid it won't be enough spring for 20lbs of boost. They would work on the exhaust side but intake i would suggest more.
I would not be affraid of putting 200lbs on the seat at all with that setup.
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Definitley very little clearance(.020) on many of the seals at full lift. Not sure what the springs were doing either with the heavy valvetrain and 20 psi. No specs on the current springs other than the pressures. They are 1.5" diameter duals.
I would deffinately go with duals as you are pushing 20 psi through the engine. We do have a titanium retainer for the spring. It is a mini 8 wieghing 10.4 grams (R532) the seat to match would be the S128. The 1530 was actually produced as a circle track endurance spring.
As far as the 1521 is concerend i am affraid it won't be enough spring for 20lbs of boost. They would work on the exhaust side but intake i would suggest more.
I would not be affraid of putting 200lbs on the seat at all with that setup.
As far as the 1521 is concerend i am affraid it won't be enough spring for 20lbs of boost. They would work on the exhaust side but intake i would suggest more.
I would not be affraid of putting 200lbs on the seat at all with that setup.
What ratio are those rockers?
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I am shocked that only 160lbs on the seat is controlling 20lbs. of boost.
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Verdad Gallardo I bet a better set of springs are in order. Either the pac springs as mentioned like the 1530 or any of their larger OD offerings with the appropriate seats etc, or the manley set. We carry the Pac springs here (most of them) and can set them up quite a few ways. We also have the Manleys as well. There are so many choices, but spring pressure is in your favor.
Keeping in mind the PI/Mast valves are fairly long & heavy I agree a good spring upgrade is probably needed. There are lots of good spring options, but a call to Cary @ PI might be a good starting spot.
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Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
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Jason
Co-Owner, Texas Speed & Performance, Ltd.
2005 Twin Turbo C6
404cid Stroker, 67mm Twins
994rwhp/902lb ft @ 22 psi (mustang dyno) www.Texas-Speed.com
We use a K Motion K800, 200 seat, 500 open, on many boosted applications and their only $93.95 a set. TEA has the retainers and cups if you need them.
http://www.summitracing.com/parts/KMO-K-800/
http://www.summitracing.com/parts/KMO-K-800/
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LOL.....Tough to keep up with who's who. ET > PIS > Mast
So bumping up the spring pressures to say 200/500 is the consensus? Better control without too much sacrifice in durability?
So bumping up the spring pressures to say 200/500 is the consensus? Better control without too much sacrifice in durability?
Either that or use +.050" locks, +.050 retainer etc.
REV has something against moving the lock groove on the valve.
Last edited by AES Racing; Nov 15, 2010 at 02:00 PM.
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Just checked my notes here. Looks like I wrote 1.86 installed height on the intakes which had .030 shims under the seats/locators. So exhaust would be 1.89. I might have the int/exhaust switched around though- I do recall measuring 1.82 somewhere- so it could be 1.83 int/1.86 exhaust.
Last edited by DrX; Nov 15, 2010 at 01:39 PM. Reason: clarification
Been there, done that... The guys pointing you to the 190-200 seat and 500 open are right. You will need that minimum with those heads and that much boost, not to mention the added weight of the shaft mount rocker. I have always had to be very aggressive with seat pressures with Cary's heads due to the longer/larger valves, especially with 1.8 rockers. The Manley 221435's would work great. I've used them many times with great success although the PAC's and others mentioned are great springs as well.
Shane
Shane
Just checked my notes here. Looks like I wrote 1.86 installed height on the intakes which had .030 shims under the seats/locators. So exhaust would be 1.89. I might have the int/exhaust switched around though- I do recall measuring 1.82 somewhere- so it could be 1.83 int/1.86 exhaust.
keep in mind we can HS any spring to lower loads for a nominal fee. The spring rate will never change though.