Will someone weigh a stock 2.16 L92 intake valve!!!??
02-11-2007, 10:00 PM
#21
The LS7 exhaust valves are stainless and sodium filled and they are a lot longer than L92 valves (by about .300"). The LS7 valves could be fitted into a L92 head but the spring installed height would be quite tall. Also the rocker stands will need to be shimmed to correct rocker geometry.
Richard
Richard
02-11-2007, 11:29 PM
#22
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Weight of intake valve illustrates RPM shifted upward quite a biit and no real reason to go to titanium on exhaust valve. ITs inertia which will be rpm and weight dependant which cause the float.
Its not just the valve thats the problem but everything on the valvetrain.
Is why some of us where scratching heads on where to remove weight at, and rev kit came up.
I don't think theh rev kit was ever "maxed out" yett, because doing so basically takes the lifter weight out of the equation. Isky cams quoted that even if they moderately improve RPM on even a solid roller app, that they prevent lifter on solid app from leaving the lobe, greatly improving the lifter bearing life.
Pro stock bike is hitting 14,000 RPM with pushrods, is there something that can be borrowed from over there?
DOHC is tite, but the thing that really gives the F1 DOHC RPM potential is the pneumatic "valvespring". Heard this was adapted by some to pushrods in the past but it was outlawed, as usual some tangents to explore.
Its not just the valve thats the problem but everything on the valvetrain.
Is why some of us where scratching heads on where to remove weight at, and rev kit came up.
I don't think theh rev kit was ever "maxed out" yett, because doing so basically takes the lifter weight out of the equation. Isky cams quoted that even if they moderately improve RPM on even a solid roller app, that they prevent lifter on solid app from leaving the lobe, greatly improving the lifter bearing life.
Pro stock bike is hitting 14,000 RPM with pushrods, is there something that can be borrowed from over there?
DOHC is tite, but the thing that really gives the F1 DOHC RPM potential is the pneumatic "valvespring". Heard this was adapted by some to pushrods in the past but it was outlawed, as usual some tangents to explore.
02-12-2007, 05:04 PM
#26
Originally Posted by Dragaholic
Why must everything be a secret with you?
The big deal here is getting more RPM for less money, that's a hard equation to work out, always has been. Mostly it just takes the right combination of parts working together and take trade offs to get what you are looking for. The biggest problem is people keep doing the same things over and over again and getting the same dam results. You can't use cheap springs, aggressive lobes and flexable valvetrains to get something to make power and live with more and more RPM, it don't work that way.
Bret
02-12-2007, 06:14 PM
#27
Bret,
How many rpm do you believe one would have to back off going from say XER to LSK lobes, keeping everything else constant? Do you think that the 5/16th aftermarket pushrods have anything to do with the "flexible valvetrains"? Do you consider Patriot Golds to be cheap springs?
And since you compete in the engine masters challenge, maybe we'll let you get away with keeping a few secrets...
How many rpm do you believe one would have to back off going from say XER to LSK lobes, keeping everything else constant? Do you think that the 5/16th aftermarket pushrods have anything to do with the "flexible valvetrains"? Do you consider Patriot Golds to be cheap springs?
And since you compete in the engine masters challenge, maybe we'll let you get away with keeping a few secrets...
02-12-2007, 06:31 PM
#28
Compared to what lobes really..... It's a full design. Depends on your springs (all of them pushrods and rockers included), mass (all of them, spring, valve, retainer, lock) and the lobes. There can be little changes to the lobes and you can see 200rpm and it LOOKS like the same cam card. Hell how you setup the springs is part of that. Good 5/16 pushrods in a LS motor are even being taxed with the rocker ratio.
The LSK lobes should get you MORE RPM not less, due to the lift but instability/bounce might come at a earlier RPM with the wrong combination. I know PAC is doing some spintron stuff to come up with a spring that works with the LSK lobes well. Last I heard nothing is good enough yet. Again I think it's a combination of things in the end. People just don't pay attention to details (not PAC, not to inferr that they are doing the right thing) but I think as a group there is not enough scientic tests done to get to the problem.
I'd really like to know more about those Patriot springs. I just can't believe you can put Ti barstock with Kobe quality pure spring wire and come up with a cheap spring and retainer setup. (You can't) To take money out you have to be doing something less, or buying something really cheaply, either machine time, spring wire, ti quality. I realize there is a advantage to large quantities but I guess I missed that Econ class where you lock your money into materials and then don't get a return on that money when you are waiting for the products to sell? I don't know the economies or specifics of those parts so I can't say anything on that.
I do know that you just can't get something for nothing unless someone is getting passed a tube of KY when they get paid.
Bret
The LSK lobes should get you MORE RPM not less, due to the lift but instability/bounce might come at a earlier RPM with the wrong combination. I know PAC is doing some spintron stuff to come up with a spring that works with the LSK lobes well. Last I heard nothing is good enough yet. Again I think it's a combination of things in the end. People just don't pay attention to details (not PAC, not to inferr that they are doing the right thing) but I think as a group there is not enough scientic tests done to get to the problem.
I'd really like to know more about those Patriot springs. I just can't believe you can put Ti barstock with Kobe quality pure spring wire and come up with a cheap spring and retainer setup. (You can't) To take money out you have to be doing something less, or buying something really cheaply, either machine time, spring wire, ti quality. I realize there is a advantage to large quantities but I guess I missed that Econ class where you lock your money into materials and then don't get a return on that money when you are waiting for the products to sell? I don't know the economies or specifics of those parts so I can't say anything on that.
I do know that you just can't get something for nothing unless someone is getting passed a tube of KY when they get paid.
Bret
02-13-2007, 03:43 PM
#32
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The exhaust valves are hollow the intakes are titanium with lash caps, I am quite sure they are longer and if my memory serves me........ + .100 sounds correct.
02-13-2007, 04:40 PM
#33
What about 2002 LS6 exhuast valves?
Are they 1.55", or 1.59" like the L92?
Supposedly they only weigh 63 grams!
From http://www.idavette.net/hib/02ls6/page2.htm
"The ’01 intake weighed 99 grams but the ’02 weighs only 76. The ’01 exhaust weighed 86 grams but the ’02 exhaust weighs 63 grams."
Are they 1.55", or 1.59" like the L92?
Supposedly they only weigh 63 grams!
From http://www.idavette.net/hib/02ls6/page2.htm
"The ’01 intake weighed 99 grams but the ’02 weighs only 76. The ’01 exhaust weighed 86 grams but the ’02 exhaust weighs 63 grams."
02-14-2007, 11:32 AM
#35
Valve Weights To give an idea of how things have changed:
Big Block Stainless OEM Valves: 2.19 intake - 151.2 g., 2.25 intake - 162.4 g. and 1.72 exhaust - 121.8 g.
I didn't have a 2.3 intake or a 1.88 available, but I'm sure they would be grim indeed!
Be glad that you didn't have to deal with these!
Big Block Stainless OEM Valves: 2.19 intake - 151.2 g., 2.25 intake - 162.4 g. and 1.72 exhaust - 121.8 g.
I didn't have a 2.3 intake or a 1.88 available, but I'm sure they would be grim indeed!
Be glad that you didn't have to deal with these!
12-06-2018, 07:56 PM
#38
TECH Senior Member
