1. What is Rocker Arm Lift?

The rocker arm lift determines how much the valve opens based on the camshaft profile and the rocker arm ratio. It's a crucial measurement for engine performance as it affects airflow into and out of the combustion chamber.

2. How Does the Calculator Work?

The calculator uses the rocker arm lift formula:

Where:

• \( \text{Valve Lift} \) — How far the valve opens (mm)
• \( \text{Cam Lift} \) — Maximum lift of the cam lobe (mm)
• \( \text{Ratio} \) — Rocker arm ratio (typically 1.1-1.8)

Explanation: The rocker arm multiplies the cam lift by its ratio to determine actual valve movement.

3. Importance of Valve Lift Calculation

Details: Proper valve lift calculation is essential for engine tuning, ensuring proper valve-to-piston clearance, and optimizing engine breathing for performance.

4. Using the Calculator

Tips: Enter cam lift in millimeters and the rocker arm ratio (typically stamped on the rocker arm or specified by manufacturer). 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 1.1:1 and 1.8:1, with 1.5:1 and 1.6:1 being common performance ratios.

Q2: How does valve lift affect performance?
A: Greater lift generally improves high-RPM power by allowing more airflow, but requires careful tuning of other components.

Q3: Can I increase valve lift by changing rocker arms?
A: Yes, higher ratio rocker arms will increase lift without changing cams, but may require valve spring upgrades.

Q4: What are the risks of too much valve lift?
A: Excessive lift can cause piston-to-valve contact, spring bind, or accelerated wear if not properly engineered.

Q5: Should I measure actual lift or rely on calculations?
A: For critical applications, always verify actual lift at the valve as manufacturing tolerances may vary.