1. What is Valve Lift?

Valve lift refers to the maximum distance the valve moves away from its seat during the camshaft's rotation. It's a critical factor in engine performance as it determines how much air/fuel mixture can enter or exit the combustion chamber.

2. How Does the Calculator Work?

The calculator uses the valve lift formula:

Where:

• \( \text{Cam Lift} \) — The maximum lift of the cam lobe (mm)
• \( \text{Ratio} \) — The rocker arm ratio (decimal)

Explanation: The rocker arm ratio multiplies the cam lift to determine the actual valve movement. A higher ratio results in greater valve lift for the same cam profile.

3. Importance of Valve Lift Calculation

Details: Proper valve lift calculation is essential for engine tuning, ensuring optimal airflow while preventing valve-to-piston contact. It affects engine power, torque, and efficiency.

4. Using the Calculator

Tips: Enter cam lift in millimeters and the rocker arm ratio as a decimal (e.g., 1.5:1 ratio is entered as 1.5). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical rocker arm ratio?
A: Most production engines have ratios between 1.5:1 and 1.8:1, though performance engines may use higher ratios.

Q2: How does valve lift affect performance?
A: Increased lift generally improves airflow and power, but only up to the point where the port becomes the limiting factor.

Q3: What's the relationship between lift and duration?
A: While lift determines how far the valve opens, duration determines how long it stays open. Both affect engine performance characteristics.

Q4: Can valve lift be too high?
A: Yes, excessive lift can cause valve float, increased wear, or piston-to-valve contact if not properly engineered.

Q5: How do I measure cam lift?
A: Cam lift is typically measured with a dial indicator at the cam lobe, subtracting the base circle radius from the lobe's highest point.