Valve springs...
Thread Starter
Senior Member
Joined: Sep 2001
Posts: 760
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From: Fayetteville NC
Vehicle: 2000 Tib
Valve springs...
so i was readin about them a lil and heard they would speed up the time taken to get to the top of the power band...so is there any designs on these for our cars? has anyone else looked into them?
or is my info incorrect? the IDEA sounds cool...like pulleys sound cool...
your opinions?
or is my info incorrect? the IDEA sounds cool...like pulleys sound cool...
your opinions?
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Joined: Sep 2001
Posts: 10,795
Likes: 5
From: Pflugerville, TX
Vehicle: 2000 Elantra
aside from being too light for the cam, how would they speed anything up? what, you want valves just sorta barely making contact with the seats to rev faster?
How else would it work but to lower the rated spring strength?
How else would it work but to lower the rated spring strength?
Super Moderator
Joined: May 2001
Posts: 11,851
Likes: 2
From: Rancho Palos Verdes, CA
Vehicle: 2008 Toyota Prius 2006 Suzuki SV650S
lighter valve springs, with the same tension would allow the engine to rev faster. The mass of the valves, the springs and the valve guides, and to some extent, the cams themselves affect the top RPM of an engine, and how fast it can reach top RPM under no load.
However, a lighter flywheel would have more effect and be cheaper than ligher titanium valve springs. Also, since our valve train uses hydraluicly operated lash adjusters, these effectivly limit the top RPM of the valve train more than valve float or spring weight does.
Don't get me wrong, If I was building up a 100% cost is no object race motor, I would be replacing everything I could with titanium this and that...but for us average street guys, they are not worth the expense. Go with a lighter flywheel.
Also...light weight (titanium) valves would have more of an effect that the valve springs themselves. Since the valve springs only compress, then extend, their weight is not so important as their spring rate. But the weight of the valve directly affects how fast it can open, and how much force is required to open it, and how much spring pressure is required to close it. The heavier the valve, the more you need to worry about valve "float", where the mass and interia of the valve lift it off of the cam lobe, and then it "smacks" back into the cam lobe, and litterally bounces back home. To stop valve float you either need lighter valves, or stiffer valve springs. Valve springs that are TOO stiff cause unwanted drag on the valve guide/cam lobe interface, and also cause the valve to litterally crash into the valve seat, wearing out the valve seat significantly faster.
However, a lighter flywheel would have more effect and be cheaper than ligher titanium valve springs. Also, since our valve train uses hydraluicly operated lash adjusters, these effectivly limit the top RPM of the valve train more than valve float or spring weight does.
Don't get me wrong, If I was building up a 100% cost is no object race motor, I would be replacing everything I could with titanium this and that...but for us average street guys, they are not worth the expense. Go with a lighter flywheel.
Also...light weight (titanium) valves would have more of an effect that the valve springs themselves. Since the valve springs only compress, then extend, their weight is not so important as their spring rate. But the weight of the valve directly affects how fast it can open, and how much force is required to open it, and how much spring pressure is required to close it. The heavier the valve, the more you need to worry about valve "float", where the mass and interia of the valve lift it off of the cam lobe, and then it "smacks" back into the cam lobe, and litterally bounces back home. To stop valve float you either need lighter valves, or stiffer valve springs. Valve springs that are TOO stiff cause unwanted drag on the valve guide/cam lobe interface, and also cause the valve to litterally crash into the valve seat, wearing out the valve seat significantly faster.