what would the valve stem look like if I where getting into valve float I have lost .4 and 4-5 mph in the 1/8 I just run a comp test and a leak down test and found no problems there no more than 3% leakage

not sure but you should hear valve float??
flat tappet cam??
torque converter?

solid roller lash has not changed converter only has about 25 passes motor sounds no different.

Valve float, unless its really major float is pretty hard to hear, We chased a valve float problem < so I thought > the year before last and found it to be a undersized needle and seat orifice in the rear bowl, well hell we could have used new springs in another 500 passes any how, I don't know of a way of checking by the valve stem, unless its loose in the guide,

I hear nothing but I have a few stems that have an odd looking pattern on the tip

Valve float hammers the locks and retainers. Remove a few springs and check the lock OD and retainer ID for signs of trouble,you may also find the retainers difficult to remove.

I had a similar problem some years ago, checked everything, found nothing, until I put in new plug wires...

plug wires are MSD and only have about 50 passes on them

If it's happened all the sudden, you should be able to see it in the valve spring pressures...

On those heads the valves shouldn't rotate much beyond their initial assembly. If you notice multiple (and by multiple, I mean more than two) roller patterns on the valve tip, this usually means it's floating. What cam, lifters and rpm are you running?

Erson solid roller 246/254@50 592 lift Crane lifters 65-6800

There are SpinTron vids around showing the entire spring pack (bottom cup and all 3 springs) jumping right off the head and squeezing together in the middle.

Can't sleep after watching that.

Unless the spring has a rotator, the valve shouldn't rotate if the spring is doing it's job in keeping the valve under control. I've seen that video you're talking about but that's extreme RPM and showing what happens to the valve spring under those conditions. I've pulled tons of heads apart and only see two roller patterns on the tip of the valves. The first from when the engine was first started, and the second, after the spring rotated the valve a bit and the valve settled into it's position.

Oh and to answer your question, the spring, keepers and retainer are what keeps the valve from rotating. Unless it's a multi groove, then they'll spin as the grooves keep the retainer located and not the press on the valve stem as in a single groove setup.

It's not the high speed...

http://www.youtube.com/watch?v=019Jyn9oB5k

Interesting though, I've seen some that rotate, and some that don't.

In general it seems like the larger springs with an opposite wound inner spring rotate less vs. the single spring stuff.

I can't see that it's related to valve float though because I found some really nasty valve float videos that didn't rotate, as well as some clean low RPM stuff that did rotate...

VALVES "generally" (when everything is right) don't rotate.

Float/spring surge/harmonics will allow them to move around some, giving the crazy looking roller tip wear patterns you occasionally see. Otherwise you almost always just see straight across uniform single wear pattern on the tip & can see the valve has been sitting in same position it's entire running life...... Also when you find a valve that has tremendous stem wear (often see it in high offset rocker ratio heads) The wear is perfectly consistent (I know I'm not describing that right but) I just disassembled some W5's off a +.675" offset rocker motor few months ago that had alot of run time & some of intake stems were worn as much as .002", & they wore in one spot as valve was consistently sitting in same area being side loaded the same for pass after pass.

I'm not going to get into a tech discussion about why/why not, but I agree, anyone who has disassembled any # of heads & looked @ wear patterns knows they don't.

I understand offset rockers undergo extreme side loading themselves
but, don't see any possible way a pushrod/rocker arm can transfer
any side load to the valve stem.

Prolonged intervals in tear-downs might result in stem wear perpendicular
to the rocker shaft but, I can't envision the side loading.

I'd be interested in the tech discussion.

I agree - there are reliable reports of local wear, but exactly how does this happen? Is the long lever bending sideways as it depresses the stem?

The observed condition (no rotation during normal use) had me a bit puzzled, until I sussed through it.

The spring (let's use only one just for clarity) will tend to rotate as it compresses, since the new height is obtained by reduced the pitch, in fact the amount of rotation is going to be a function of the original pitch angle and more or less distributed among the "active" coils.

Then why doesn't the entire spring rotate on the head?

The coefficients of friction of the spring's seated coil and the head surface are "gritty" enough that the traction resists movement.
If they were lapped in to a mirror polish, they might move. It's a happy coincidence that for normal spring design this relationship works.

MP sells a lash cap with keepers that have a groove in the keeper for the cap to drop in, They came on our w5s when we got them, It seems that it locks up the keepers from moving around @ high rpm by not letting them open at the top.

But... what exactly is moving?

If the rocker is taking up the clearance in opposite directions at each end, the mis-align is limited to a trig function of the clearance and the length of the rocker on the shaft axis from the roller to the pushrod.
Senior moment and I don't have the actual rocker dims, but this looks like the clearance ÷ body length = arctan of the mis-align angle.
If the clearance is .002" and the body is 1" long (on the shaft axis), the angle is only .11° (about 1/10th of a degree).
That should be detected at all. If the rocker is longer than that, the angle is even less.
Even if the bushing is toast (.010"), this is still only .57° (1/2 of a degree).

The only other answer ICTO is that the lever is bending away from the center, and introducing a 3rd axis to the roller tip.
If it really bends that much, there isn't enough cross-section in the stressed area - this is a design problem.

I am not sure what exactly in moving around @ valve float but I was looking at it from the possibility of the valve keeper / retainer seperating allowing the keeper to work in the valve stem,The lash cap with the groove holds the keepers tight to the valve stem without spring pressure, I thought the lash cap with keeper were designed to work together to stop this movement? I played with this set up on the bench with the valves out of the head and could not remove the keepers from the valve with the lash cap snapped down into the groove.

Woody I know you are asking about valve float. But my car slowed .5 and 5 mph at the track this year. I was carb jetting. I couldn't believe that 2 jet sizes in the frt and 2 in the back could make that much difference in power. Jim