I don't know if i have this problem or not but what is floating valves and how do you get rid of this condition?? Thanks, Dave.

flaoting valves are when your valves are not fully closing before the next opening cycle. the 2 things that cause this are high rpms & soft valve springs. the normal way to get rid of this is not rev out motor. if you have a 2.8, theres no reason to rev out past 5000 - your WAY past your powerband, just shift, and be back into your powerband - you'll be faster that way. the next fix is stronger valve springs.

Valve float occurrs when the valve spring is unable to close the valve before the cam causes it to open again. The valve effectively "floats" in the open or partially open position, resulting in a loss of compression.

In a normally functioning engine, valve float should not occur unless the engine is run at RPMs above that which the valve train was designed for. Weak or broken valve springs could cause it to happen at lower RPMs, however.

What symptoms are you experiencing that prompted you ask this?

Floating valves happen when either the valve springs or the lifter cannot react fast enough with the RPM of the engine.
This causes the valve to "float". By floating means the valve doesn't close fast enough causing less compression and/or the valve doesn't open all the way causing not enough fuel/air into the cylinders. Basically you do not have enough pressure to operate the valve correctly. Floating valve train can also damage rockers and bend pushrods.
With pushrod engines, even with stock lifters and springs, The cam could spin faster than the valve train is capable of moving and cause floating valves if the engine is near redline or over-rev'd. It is more prone with hydraulic lifter pushrod valve trains as you have the spring and the inside of the lifter moving. Solid lifters assist in causing less float, But require more maintenance to keep the adjusted.
To correct this you can get a set of performance valve springs and lifters.

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[This message has been edited by Oreif (edited 06-13-2005).]

What are floating valves? They're bad, that's what they are. Many explanations above, all good. RPM related, won't happen on a stock Fiero motor because the power runs out long before the springs do.

JazzMan

You can also cause this by running a silly ass cam without the recommended upgraded springs.

Above explanations were good and yes there's nothing to be gained by reving a stock pushrod 2.8 - 3.4 past 5k. Here's something interesting on this topic, we were quite surprised to discover on the dyno with Matt's stock 3.4 (except for our intake) that the stock GM valve train could go all the way to 6,500 rpm without a hickup! Could maybe have gone even higher, but we set chip limit to 6.5k. Not wanting to waste Matt's motor we didn't bump the limit up any. With the intake there was power being made, up there. While I don't regreat putting race type valve springs, lifters etc in my 2.8 engine, after seeing that dyno run........

Is Matt's engine a crate engine or out of a Camaro/Firebird? The Camaro/Firebird engine has the same soft, short, springs and small cam as the 2.8 while the crate engine has a larger cam and taller, stronger, springs.