Home
Back
Valve Lift Formula:
| From: | To: |
Valve lift refers to the maximum distance that a valve opens from its seat in an internal combustion engine. It is a critical parameter that affects engine breathing, performance, and efficiency.
The calculator uses the valve lift formula:
Where:
Explanation: The rocker arm multiplies the cam lift to produce the actual valve lift. A higher rocker ratio results in greater valve lift for the same cam profile.
Details: Proper valve lift calculation is essential for engine tuning, performance optimization, and ensuring proper valve-to-piston clearance. It directly impacts airflow into and out of the combustion chamber.
Tips: Enter cam lift in inches and rocker ratio as a dimensionless value. Both values must be positive numbers greater than zero for accurate calculation.
Q1: What is a typical rocker ratio range?
A: Most production engines have rocker 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 valve lift affect engine performance?
A: Higher valve lift generally improves airflow and increases power, but must be balanced with other factors like duration and lobe separation angle.
Q3: Can I increase valve lift without changing camshaft?
A: Yes, by installing higher ratio rocker arms, but this requires checking for proper valve train geometry and piston-to-valve clearance.
Q4: What are the limitations of increasing valve lift?
A: Excessive valve lift can cause valve float, increased wear, and may require upgraded valve springs and retainers. Piston-to-valve clearance must always be verified.
Q5: How do I measure cam lift accurately?
A: Cam lift is best measured with a dial indicator while rotating the camshaft, measuring the maximum lobe height minus the base circle diameter.