What causes engine valve float?
Valve float occurs when the valvesprings are incapable of holding the valvetrain against the camshaft lobe after peak lift. This happens when either the weight of the combined valvetrain components or the rpm speed of the engine creates so much inertia that the spring is no longer able to control the valve.
What happens if you float a valve?
When valves float, there are no closing mechanisms within the cylinder heads, thus allowing an engine to fail and malfunction. Piston, valve, and camshaft damage can occur due to valve float. An engine blow can result in catastrophic engine failure if a valve goes off for a period of time.
How do you tell if your valves are floating?
How is it identified?
- Mild valve float can be felt as power falling off quickly at high rpm.
- Severe valve float will be heard as a sputtering sound at peak rpm.
Does valve float cause backfire?
No backfires, no popping thru the exhaust, just runs real crappy at high rpm.
How do you fix valve floats?
Valve float can also be prevented by using lighter valvetrain components. Titanium valves, retainers, and pushrods are commonly used for this purpose. Undercut valves can both increase flow and decrease weight. Also, by using more than the traditional two valves per cylinder, smaller and lighter valves can be used.
What is valve bounce?
A valve bounce is the bouncing of a poppet valve on its seat when it is closing. Valve bounce can occur if the valve spring is weak and operated at high speeds. Valve bounce is when the valve hits its seat and then bounces back off of it. Valve bounce can be minimized by testing the valve springs very closely.
How do you lower a valve float?
What happens when valve spring tension is too low?
If the spring pressures are too low, a condition called “Valve Float” will occur.
How do you stop valves from floating?
To fix a loft problem, increase your valve spring open pressure. When a valve bounces off the seat, the engine loses compression. To fix a bounce problem, increase your valve spring seat pressure. Lighter valvetrain parts can also help with valve float issues.
Will weak valve springs symptoms?
Symptoms of Weak Valve Springs Weak valve springs will typically cause misfiring and a loss of power as engine speed increases. The engine may start and idle fine, or run normally up to 3500 to 4000 RPM.