Hollow stem valves?
#2007436
02/07/16 04:50 PM
02/07/16 04:50 PM
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gregsdart
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I run through the traps as high as 7800 rpm, and figure it might be worth going to a hollow stem steel valve? I plan on going to an .850 lift combo, and may need an additional .050 length beyond the BBC 5.444 (+.100)valves now in the heads. Would appreciate anyone's experience with these.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Hollow stem valves?
[Re: gregsdart]
#2007452
02/07/16 05:17 PM
02/07/16 05:17 PM
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fast68plymouth
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If you think you need hollow stems....... You need titanium.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Hollow stem valves?
[Re: fast68plymouth]
#2007507
02/07/16 06:50 PM
02/07/16 06:50 PM
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Brian Hafliger
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Exactly! Hollow stems are for class racing or hyd. roller stuff...Ti. is for you Greg! And watch the ex. valve weight too as it's important at that rpm as well.
Brian Hafliger
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Re: Hollow stem valves?
[Re: fast68plymouth]
#2007768
02/08/16 02:40 AM
02/08/16 02:40 AM
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gregsdart
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If you think you need hollow stems....... You need titanium. Thanks for the input, guys. I don't know if I need hollow stems or Ti valves, but figure I may be on the edge with the steel stuff? 16 Ti valves would put a hurt on what I have budgeted for this season for freshen up. My thinking is, I have a mild exhaust lobe ; 296 @ .050 of duration, only .684 lift with 1.55 rockers, .748 with 1.7 rockers. I am running the 1.55 rockers at the moment. I hope I can get by on that side by carefully setting up the springs, and running enough pressure. At 2.000 I.H. I have 310 lbs on the seat, comp 947 triples. I can run them tighter and gain seat pressure if needed? I have a new set of slicks that will bring the rpm down to about 7600 rpm, which will help. I shift at 7100. The intakes are what I am more concerned about, 2.300 + .100 long BBC stainless valves. I will be going to 2.050 I. H. and Comp 948 springs, which will be about 370 lbs on the seat. I should be about .085 to coil bind on the intakes, a lot more on the exhaust. I have read that the hollow valves will add about half the rpm range you can gain with Ti valves, and eight steel hollow stem intakes won't break the bank. I need to freshen the valve job anyway. So that is where all this started, hoping to gain a bit of horsepower, and add a little margin to my rpm range on a budget. Would appreciate opinions on the plan.
Last edited by gregsdart; 02/08/16 02:51 AM.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Hollow stem valves?
[Re: dvw]
#2007849
02/08/16 11:42 AM
02/08/16 11:42 AM
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gregsdart
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Ken, I didn't see anything in 2.300 either, but figure someone may make them on request. Doug, I do shift it at 7100 on an rpm switch now, but the trap rpm is where it might get a bit high. My cams that I have run all look very good.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Hollow stem valves?
[Re: gregsdart]
#2007868
02/08/16 12:14 PM
02/08/16 12:14 PM
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dvw
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Greg have you tried taking gear out of it and running lower trap rpm? I don't think it really hurts mine, I'm heavier than you. MPH vs ET, 9.02@151, 3350, 4.10, 10.5wx31. Not very aerodynamic either. Titanium is WAY out of my pay grade. Doug
Last edited by dvw; 02/08/16 08:07 PM.
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Re: Hollow stem valves?
[Re: gregsdart]
#2007921
02/08/16 02:21 PM
02/08/16 02:21 PM
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Al_Alguire
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IMO you will be WAY better off going to a titanium valve. A lot of weight in a steel valve that size
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Hollow stem valves?
[Re: gregsdart]
#2008067
02/08/16 06:21 PM
02/08/16 06:21 PM
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MR_P_BODY
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I dont think you would need Ti exhaust valves.. they are lighter than the intakes... sure you could put them in if you wanted to lighten up everything and then use different(lighter springs).. my B-1 stuff was 2.4 Ti intakes with steel exhaust.. I was gonna turn that to 9000
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Re: Hollow stem valves?
[Re: MR_P_BODY]
#2008122
02/08/16 07:39 PM
02/08/16 07:39 PM
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Brian Hafliger
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I dont think you would need Ti exhaust valves.. they are lighter than the intakes... sure you could put them in if you wanted to lighten up everything and then use different(lighter springs).. my B-1 stuff was 2.4 Ti intakes with steel exhaust.. I was gonna turn that to 9000 If your ex. valve is heavier than 125g, you might not like the results! Yes you can use heavier springs, but you will lose a bit of power that way...guess it depends on how much power your willing to lose or pay for. 9000 is a lot of rpm for a steel valve over that weight...
Brian Hafliger
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