1. What is Piston Compression Height?

Compression Height (CH) is the distance from the centerline of the wrist pin to the top of the piston. It's a critical dimension for determining proper engine assembly and compression ratio.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( CH \) — Compression Height (in)
• \( \text{Pin to Top} \) — Distance from pin center to piston top (in)
• \( \text{Dish Depth} \) — Depth of piston dish or dome (in)

Explanation: The formula accounts for both the basic pin-to-top measurement and any modifications to the piston crown.

3. Importance of Compression Height

Details: Proper compression height ensures correct rod length selection, proper quench/squish area, and prevents piston-to-head contact. It directly affects engine compression ratio and performance.

4. Using the Calculator

Tips: Measure pin-to-top carefully from the pin centerline to the piston deck. Dish depth is positive for dished pistons, negative for domed pistons.

5. Frequently Asked Questions (FAQ)

Q1: How precise should measurements be?
A: For performance engines, measure to 0.001" precision. Standard builds can use 0.005" precision.

Q2: What's a typical CH range for small engines?
A: Small engine CH typically ranges from 0.800" to 1.200" depending on application.

Q3: How does CH affect rod length selection?
A: CH + rod length + stroke/2 must equal deck height minus desired squish/quench.

Q4: Can I use this for domed pistons?
A: Yes, enter dish depth as a negative value for domed pistons.

Q5: What if my piston has valve reliefs?
A: Include valve relief depth in your dish depth measurement if they affect the compression volume.