1. What is the Wallace Method?

The Wallace method is a simple and accurate way to determine rocker arm ratio by measuring actual valve lift and cam lift. The ratio is important for understanding valve train geometry and performance.

2. How Does the Calculator Work?

The calculator uses the Wallace method formula:

Where:

• \( Measured\ Valve\ Lift \) — Actual valve movement measured at the valve stem (mm)
• \( Measured\ Cam\ Lift \) — Cam lobe lift measured at the lifter (mm)

Explanation: The ratio shows how much the rocker arm multiplies the cam's motion to produce valve lift.

3. Importance of Rocker Arm Ratio

Details: Accurate ratio measurement is crucial for engine building, performance tuning, and ensuring proper valve train geometry. It affects valve timing, lift duration, and spring pressures.

4. Using the Calculator

Tips: Measure both valve lift and cam lift precisely in millimeters. The measurements should be taken at maximum lift points. Both values must be greater than zero.

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, but performance engines may use higher ratios.

Q2: How does ratio affect engine performance?
A: Higher ratios increase valve lift and acceleration but may require stronger valve springs and can affect durability.

Q3: Should I measure hot or cold?
A: Measurements are typically made with the engine cold, as this is when most adjustments are made.

Q4: How precise should my measurements be?
A: For accurate results, measure to at least 0.01mm precision using a dial indicator.

Q5: Does ratio affect valve timing?
A: While it doesn't change cam timing directly, it affects when valves reach specific lift points during the cycle.