1. What is Valve Lift Calculation?

The valve lift calculation determines how far the valve opens in an engine based on camshaft specifications and rocker arm ratio. It's a critical measurement for engine performance and airflow optimization.

2. How Does the Calculator Work?

The calculator uses the valve lift formula:

Where:

• \( \text{Cam Lift} \) — Maximum lift of the camshaft lobe (mm)
• \( \text{Rocker Ratio} \) — Mechanical advantage of the rocker arm (dimensionless)

Explanation: The rocker arm multiplies the camshaft's lobe lift to produce greater valve movement, improving engine breathing.

3. Importance of Valve Lift

Details: Proper valve lift affects engine performance, volumetric efficiency, and power output. Too much lift can cause valve train stress, while too little restricts airflow.

4. Using the Calculator

Tips: Enter cam lift in millimeters (typically 5-15mm for performance engines) and rocker ratio (typically 1.5-1.8:1). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical rocker arm ratio?
A: Most production engines use 1.5:1 to 1.7:1 ratios, while performance engines may use 1.8:1 or higher.

Q2: How does valve lift affect engine performance?
A: Increased lift generally improves high-RPM power but may reduce low-end torque. Optimal lift depends on engine design and application.

Q3: Can I use this for overhead cam engines?
A: This calculation applies primarily to pushrod engines. OHC engines without rocker arms use cam lift directly.

Q4: What's the maximum safe valve lift?
A: Maximum lift is limited by piston-to-valve clearance, spring pressure, and valve train stability. Consult your engine specifications.

Q5: Does rocker ratio affect valve timing?
A: While ratio changes lift, it doesn't alter duration or timing events - those are determined by camshaft design.