Stainless 2.2" intake valves in LS7 heads, valve float? need titanium?
#1
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From: Bakersfield, CA
Stainless 2.2" intake valves in LS7 heads, valve float? need titanium?
Ive got a set of heads coming from Texas-Speed that im putting together (first set of custom LS7 heads that ive done). So im thinking about trying to cut costs down on this motor by running stainless hollow stem valves with them. ($880 cheaper, plus i dont know how reliable the tit valves are with 1000+ rwhp on boost)
Im worried about valve float problems due to the size of valve 2.200" with quality stainless valve. This setup is a turbo setup so I will not be running alot of camshaft and im looking to have a 7000rpm shift point setup to increase reliablility etc.
The cam im thinking of is approx 239/250, with around .609/.645 @ 114+3
which i think with a set of PRC Xtreme Gold springs should have no problem with valve float on the intake side. The 1.61 exhaust stainless valves are no problem...
Combo:
PRC LS7 CNC Cylinder heads (400cfm)
Yella Terra LS7 Ultralight-shaft rockers
S-91 turbo from Jose @ FI
Im worried about valve float problems due to the size of valve 2.200" with quality stainless valve. This setup is a turbo setup so I will not be running alot of camshaft and im looking to have a 7000rpm shift point setup to increase reliablility etc.
The cam im thinking of is approx 239/250, with around .609/.645 @ 114+3
which i think with a set of PRC Xtreme Gold springs should have no problem with valve float on the intake side. The 1.61 exhaust stainless valves are no problem...
Combo:
PRC LS7 CNC Cylinder heads (400cfm)
Yella Terra LS7 Ultralight-shaft rockers
S-91 turbo from Jose @ FI
Last edited by SoCalSpd; 08-17-2008 at 10:06 PM.
#2
I'm working a little bit on a hollow stem option that I will have more info on later this week. I'm going to see if we can get a good option between the steel & titanium valves.
I'll keep ya posted!
I'll keep ya posted!
__________________
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
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
#3
Ive got a set of heads coming from Texas-Speed that im putting together (first set of custom LS7 heads that ive done). So im thinking about trying to cut costs down on this motor by running stainless hollow stem valves with them. ($880 cheaper, plus i dont know how reliable the tit valves are with 1000+ rwhp on boost)
Im worried about valve float problems due to the size of valve 2.200" with quality stainless valve. This setup is a turbo setup so I will not be running alot of camshaft and im looking to have a 7000rpm shift point setup to increase reliablility etc.
The cam im thinking of is approx 239/250, with around .609/.645 @ 114+3
which i think with a set of PRC Xtreme Gold springs should have no problem with valve float on the intake side. The 1.61 exhaust stainless valves are no problem...
Combo:
LsX block 444" (4.155"x4.100)
PRC LS7 CNC Cylinder heads (400cfm)
Yella Terra LS7 Ultralight-shaft rockers
S-91 turbo from Jose @ FI
Im worried about valve float problems due to the size of valve 2.200" with quality stainless valve. This setup is a turbo setup so I will not be running alot of camshaft and im looking to have a 7000rpm shift point setup to increase reliablility etc.
The cam im thinking of is approx 239/250, with around .609/.645 @ 114+3
which i think with a set of PRC Xtreme Gold springs should have no problem with valve float on the intake side. The 1.61 exhaust stainless valves are no problem...
Combo:
LsX block 444" (4.155"x4.100)
PRC LS7 CNC Cylinder heads (400cfm)
Yella Terra LS7 Ultralight-shaft rockers
S-91 turbo from Jose @ FI
#6
Ive got a set of heads coming from Texas-Speed that im putting together (first set of custom LS7 heads that ive done). So im thinking about trying to cut costs down on this motor by running stainless hollow stem valves with them. ($880 cheaper, plus i dont know how reliable the tit valves are with 1000+ rwhp on boost)
Im worried about valve float problems due to the size of valve 2.200" with quality stainless valve. This setup is a turbo setup so I will not be running alot of camshaft and im looking to have a 7000rpm shift point setup to increase reliablility etc.
The cam im thinking of is approx 239/250, with around .609/.645 @ 114+3
which i think with a set of PRC Xtreme Gold springs should have no problem with valve float on the intake side. The 1.61 exhaust stainless valves are no problem...
Combo:
PRC LS7 CNC Cylinder heads (400cfm)
Yella Terra LS7 Ultralight-shaft rockers
S-91 turbo from Jose @ FI
Im worried about valve float problems due to the size of valve 2.200" with quality stainless valve. This setup is a turbo setup so I will not be running alot of camshaft and im looking to have a 7000rpm shift point setup to increase reliablility etc.
The cam im thinking of is approx 239/250, with around .609/.645 @ 114+3
which i think with a set of PRC Xtreme Gold springs should have no problem with valve float on the intake side. The 1.61 exhaust stainless valves are no problem...
Combo:
PRC LS7 CNC Cylinder heads (400cfm)
Yella Terra LS7 Ultralight-shaft rockers
S-91 turbo from Jose @ FI
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#8
#9
#10
I was running a set of Manley Nextec springs with Ti retainers and super 7 locks with a set of Harland Sharp roller tip rockers on my LS7 heads with Ti intake and sodium filled exhaust valves. The springs were good to .650 lift and tested 135lbs at the seat, 385lbs at .650 lift. But, due to the extra tip weight of the roller tip rocker, the valves would float at 6300.
Becuase of that, I would guess you're going to have to run some pretty stiff springs after having the Yella Terras and the stainless valves. Probably too much weight for 7000 without really stiff springs. But, I don't know what the PRC Xtreme Gold springs have for pressure.
Becuase of that, I would guess you're going to have to run some pretty stiff springs after having the Yella Terras and the stainless valves. Probably too much weight for 7000 without really stiff springs. But, I don't know what the PRC Xtreme Gold springs have for pressure.
#12
Shimming didn't work for me, I had to go with stiffer springs. To be honest, though, I don't even know what springs I'm running now. It was on the dyno that we realized the valves were floating and I wasn't there when the builder ordered and installed the new springs. I was just happy as hell when I heard what we ended up making for power I forgot to ask what springs he ended up going with.
#13
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FormerVendor
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From: Bakersfield, CA
The yella terra ultra-lights's are lighter on the tip than a stock rocker actually. Harland sharps are much heavier than a YT.
Anyone have a suggestion for a good double spring with similar specs of 200/435 pressures to fit on a ls7 head?
Anyone have a suggestion for a good double spring with similar specs of 200/435 pressures to fit on a ls7 head?
Last edited by SoCalSpd; 08-18-2008 at 12:10 PM.
#14
Try a step cut on the valve pocket so you can step up to a 1.550" diameter spring. Your options expand greatly at that size.
#15
The spring I like to use is the PSI CT1225 ML. I feel it's ideal for a hyd roller turbo car as it has a low rate of 393lb/in which allows you to set it up at a high seat pressure (200@1.800) without having excessively high pressure over the nose (435@1.200).
http://psisprings.com/index.php?opti...ask=view&id=17
Only downside is price as the springs and retainers are rather expensive but it is top notch stuff. (the PSI springs, Xceldyne retainers/locks/seats cost me around $900, though they do offer a lock/retainer setup that's a bit less money)
http://psisprings.com/index.php?opti...ask=view&id=17
Only downside is price as the springs and retainers are rather expensive but it is top notch stuff. (the PSI springs, Xceldyne retainers/locks/seats cost me around $900, though they do offer a lock/retainer setup that's a bit less money)
#17
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FormerVendor
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From: Bakersfield, CA
are you sure you are going to wan to push those stainless exhaust valves with that much power and heat?
When i had my heads done i was told that at those power levels it's only a matter of time before you fatigue the stem and end up popping a head off the valve. i was told to go with inconel valves, the higher melting point of the material would greatly outweigh the increase in weight and overall cost if it does drop a head.
When i had my heads done i was told that at those power levels it's only a matter of time before you fatigue the stem and end up popping a head off the valve. i was told to go with inconel valves, the higher melting point of the material would greatly outweigh the increase in weight and overall cost if it does drop a head.
#19
I'm running manley stainless LS7 myself. Richard at WCCH set me up with some 1.450" doubles
The spring pressures are as follows; Installed height = 1.855" Seat pressure = 163lbs Open pressure = 404lbs @.600"lift 426lbs@.650" lift. The max recommended lift for these springs is .660" and the open pressure will be approx. 430lbs.
They use his custom ti retainers and were less than $600 for the springs/retainers/machine work. He suggested that I not go over .630" total lift. But he also sent me some head/intake flow charts, and WITH THE STOCK INTAKE BOLTED ON there is a huge drop flow RIGHT at .630" lift. Weird. He also stated that these pressures were about the max you could use and still retain hydraulic lifters.
The motor won't be running till next year, but I'll let you know where I float!!!
The spring pressures are as follows; Installed height = 1.855" Seat pressure = 163lbs Open pressure = 404lbs @.600"lift 426lbs@.650" lift. The max recommended lift for these springs is .660" and the open pressure will be approx. 430lbs.
They use his custom ti retainers and were less than $600 for the springs/retainers/machine work. He suggested that I not go over .630" total lift. But he also sent me some head/intake flow charts, and WITH THE STOCK INTAKE BOLTED ON there is a huge drop flow RIGHT at .630" lift. Weird. He also stated that these pressures were about the max you could use and still retain hydraulic lifters.
The motor won't be running till next year, but I'll let you know where I float!!!