I hear lots of talk about valve float at higher rpms but I have to be honest, what is it and how can you tell? What are the signs of valve float? Not that this valve float but until my car is completly warm I get some chatter from my valvetrain while cruising. This is when the temp even isn't on the gauge yet. Just more concerned about valve float though.

Thanks, Erik

Valve float can be heard as missing cylinders at high rpm. If stock springs are used, and they are alittle tired, this high rpm can start at low 5K rpm.

Valve float is the valve staying open when it is not suppose to be open, the momentum of the lifter, push rod, retainer, and valve itself may be too heavy for the spring to seat the valve. Ramp design of the camshaft may be too steep (fast) throwing the lifter off the lobe. Now, the piston comes up to TDC, and valve is open -- SMACK !!

Valve float can be physically viewed as bent push rods, broken push rod cups in rocker arms, bent valves with the head(s) removed, and its corresponding indent in the piston head. Depending upon the severity of valve floatage, any combination of one to all the mentioned visual signs can be present.

Hope this helps.......

I aggree with Everett's answer - he discribes the signs of Valve Float for higher performance engines very well.
I would in addition comment that on todays lower compression deep valve relief type pistons, where valve clearance in usually not a big problem, that valve float can also be noticed as an engine that just seams to "Lay Down" way to soon in it's power curve or as you accelerate above say 5~5,500 RPM.
This is most common on engines that have some power adder ( Bigger Cams, Intakes & Carbs) parts added to them during stock type rebuilds when the stock valve train is retained. Everett points this out in his reply.
I have had the "opportunity" to help several people out on this issue in the past several years. In one instance the guy who built the engine sold the customer a bigger carb to try to fix the problem of his engine "Popping" on the top end - "because everyone knows that means the carb is to small".
In direct response to your question, and reading your engine set-up as posted in your sig. This cam need valve springs that have greater lift capacity than most stock replacement springs, so H.P. type should have been used in your engine. You also could have a bad or missadjusted lifter(s) if you are sure it is coming from your valve train. Could even be something normal in the lifter, depending on type used. I have even chased a wierd valve noise to a problem in the rocker to spring retainer clearance - not that I think that could be your problem from your present discription, but it never hurts to pull a valve cover and 'eyeball' the valve train for odd things.
Post back with comments and someone can follow-up.

The above symptoms are correct. I believe most of the bouncing off the lobe occurs when the valve is shut and the lifter will actually bounce back off the base of the lobe, not flying off the top of the lobe under full lift.

Jody

Once you have heard valve float you can easily identify the sound. It is hard to describe sort of a rapid da-da-dat.