valve float

[Falcon67]

>What does valve float feel like?

From my experience -

Fuel - motor just stops pulling, doesn't necessarily break up but runs out of power and feels like you started dragging a trailer.  Usually, not always, recovers on the shift if you're going 1 to 2.

Float - things go to hell quick, car noses over, maybe some sound indicators if the intakes are open during the firing sequence.  Valve bounce nearly as bad.

One more like "We're out of juice" and the other more like "Mayday! We're hit, goin' in!"   

[tomsfe64]

Thanks for all the info. I'm changing the valve springs one at a time and i found a completely broken pushrod snapped off 1/2" from the top. Somehow it stayed together until i removed the rocker shaft. So i suppose that the valve hit the piston. Hopefully the new springs solves the problem.

[WConley]

If you think a valve hit a piston, you may want to check that it's not bent.  Do a compression test on all cylinders once you've got the new springs installed.

(I'm assuming you're not pulling the heads.  If you did you could just check them on the bench...)

[fryedaddy]

valve float or not,what is the most rpms anyone ever seen out of a flat tappet hydraulic cam on an fe.i have hit 7000 on my limiter during a burnout.im sure it was losing power but the rpms kept rising

[tomsfe64]

new valve springs solved it. now runs as it should. pulls hard at hi rpm.

[cammerfe]

Actually, desmodromic valve actuation goes back to the late 1800s and was used by Mercedes, in the '30s I believe, for its race cars before being used in the Ducati motorcycles.

KS