1. What is Rocker Arm Ratio Lift?

The rocker arm ratio lift calculation determines the actual valve lift based on cam lift and rocker arm geometry. It's essential for engine performance tuning and valve train design.

2. How Does the Calculator Work?

The calculator uses the rocker arm ratio formula:

Where:

• \( \text{Cam Lift} \) — The lift provided by the camshaft lobe
• \( \text{Pivot to Valve} \) — Distance from rocker pivot point to valve contact point
• \( \text{Pivot to Pushrod} \) — Distance from rocker pivot point to pushrod contact point

Explanation: The ratio between pivot-to-valve and pivot-to-pushrod distances determines how much the cam lift is multiplied to achieve the actual valve lift.

3. Importance of Valve Lift Calculation

Details: Accurate valve lift calculation is crucial for proper engine breathing, valve timing, and preventing valve-to-piston interference in high-performance engines.

4. Using the Calculator

Tips: Enter cam lift, pivot to valve distance, and pivot to pushrod distance. All values must be positive numbers. Ensure consistent units (inches or millimeters) for all measurements.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical rocker arm ratio?
A: Most production engines have ratios between 1.5:1 and 1.7:1, while performance engines may use ratios up to 2.0:1 or higher.

Q2: How does rocker ratio affect engine performance?
A: Higher ratios increase valve lift and acceleration, improving airflow at high RPM, but may require stronger valve springs and components.

Q3: Can I mix measurement units?
A: No, all measurements must use the same unit system (either all inches or all millimeters) for accurate results.

Q4: What factors affect rocker arm ratio accuracy?
A: Manufacturing tolerances, wear, rocker arm geometry, and actual pivot point location can affect the effective ratio.

Q5: When should I check rocker arm ratio?
A: During engine building, camshaft upgrades, or when troubleshooting valve train issues such as poor performance or unusual wear patterns.