1. What is Camshaft Lift?

Camshaft lift refers to the maximum displacement of the cam lobe from its base circle. It determines how far the valves open in the engine. The cam lift is calculated by dividing the valve lift by the rocker arm ratio.

2. How Does the Calculator Work?

The calculator uses the cam lift formula:

Where:

• Valve Lift — Maximum valve opening distance (mm)
• Ratio — Rocker arm ratio (decimal)

Explanation: The rocker arm ratio amplifies the camshaft's movement to create greater valve lift. This calculator reverses that calculation to determine the actual camshaft lobe height.

3. Importance of Cam Lift Calculation

Details: Knowing cam lift is essential for engine builders to verify camshaft specifications, ensure proper valve clearance, and predict engine performance characteristics.

4. Using the Calculator

Tips: Enter valve lift in millimeters and rocker ratio as a decimal (e.g., 1.5:1 ratio is entered as 1.5). Both values must be greater than zero.

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, while performance engines may use 1.8:1 or higher.

Q2: How does cam lift affect engine performance?
A: Greater cam lift typically increases airflow at high RPM, improving power, but may reduce low-RPM torque and idle quality.

Q3: Can I measure cam lift directly?
A: Yes, with a dial indicator on the cam follower or lifter while rotating the engine, but this calculation method is often more convenient.

Q4: What's the relationship between cam lift and duration?
A: While related to performance, lift and duration are separate specifications - lift measures how far the valve opens, duration measures how long.

Q5: Does this calculation work for all cam types?
A: Yes, it applies to flat tappet, roller, and overhead cam designs, as long as you know the exact rocker ratio.