Floating valves?

[Maelfyn]

What the hell do people mean when they say floating valves? I'm trying to visualize the valves floating... logically... makes no sense to me

[vvtlikick]

Well you understand that the valve "rides" the camshaft, right? Valve float is when the valve "jumps" off the camshaft, because the cam is spinning too fast. This isn't good for reliability, and it increases the risk that the valve will crash into the piston.

Remedies include: diff. cams, lighter valves and retainers, stronger valve springs, etc.

[Deaks2]

If the cam is actuating the valves too quicky for the springs to keep them in contact with the came lobe then you get valve float...

2 ways to fix it, reduce valve mass or get stiffer valve springs.

reduced valve mass allows the exisitng spring to move the valve back to the closed porotion easier.

stiffer valve springs will be more resistant, and therefore the valve will stay in contact with the cam lobe, but their may be a power penalty (increased resistance may reduce power due to the cam being attached to the crank via the chain or belt)

my buddy with a mod'ed ITR has the Mugen 9000 rpm ECU with the Mugen Head kit which includes stiffer valve spirngs and lighter valves, allowing his B18 to safely rev to 9000+ rpm.

[yakkosmurf]

Deaks2 is right on the money. The best way to eliminate float is to get stiffer valve springs. They are much cheaper than trying to get lighter valves.