1. What is Valve Lift Calculation?

The valve lift calculation determines how far the valve opens based on camshaft lift and rocker arm ratio. It's a fundamental measurement in engine design and performance tuning.

2. How Does the Calculator Work?

The calculator uses the rocker arm formula:

Where:

• Valve Lift — How far the valve opens (mm)
• Cam Lift — Camshaft lobe height (mm)
• Ratio — Rocker arm ratio (dimensionless)

Explanation: The rocker arm multiplies the camshaft's motion by its ratio to determine actual valve movement.

3. Importance of Valve Lift Calculation

Details: Proper valve lift affects engine breathing, performance, and reliability. Too much lift can cause valve-to-piston contact, while too little restricts airflow.

4. Using the Calculator

Tips: Enter cam lift in millimeters and the rocker arm ratio (typically between 1.1 and 1.8 for most engines). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical rocker arm ratio?
A: Most production engines use ratios between 1.5:1 and 1.7:1, though this varies by engine design.

Q2: How does valve lift affect performance?
A: Increased lift generally improves high-RPM power but may reduce low-end torque. Optimal lift depends on the entire valve train system.

Q3: Can I measure cam lift directly?
A: Yes, using a dial indicator on the cam follower while rotating the engine through its cycle.

Q4: What factors limit maximum valve lift?
A: Valve spring pressure, piston-to-valve clearance, and the camshaft's acceleration rates all impose practical limits.

Q5: Does rocker ratio affect duration?
A: No, ratio only affects lift. Duration is determined by the camshaft lobe design.