Written by Moore Good Ink
Lunati’s design begins at the first valve moment of the cycle, the exhaust opening point. By deliberately delaying the opening point they generate more torque from the power stroke, consequently adding more power to the crank. This process occurs throughout the rpm band and is effective as long as the exhaust gases can be properly scavenged from the chamber at high rpm.
Then, as expected, they open the intake valve before Top Dead Center. But they open it late to reduce the effects of reversion entering the intake port. They also open it FAST, inducing earlier air flow and providing more high-lift area (also known as more area under the curve). This occurs after TDC as the piston heads downward on its intake stroke, which creates high velocity in the port. If a port has high velocity and the intake valve has lots of high-lift area, the port fills the cylinder faster and has more time to fill it-thus increasing the engine’s potential horsepower and torque.
They then close the intake valve gently to prevent valve bounce and facilitate valve train reliability. Of the four timing points the exhaust closing point has the least power-producing effect on the valve train. Yet in this area Lunati exercises special care to ensure exhaust valve reliability.