Ring Gap Calculator

Ring Gap Calculator calculates the ring gap in an engine’s piston ring which is a crucial element that impacts its performance. Calculating the ideal ring gap involves a formula that takes into account the bore diameter and the desired ring end gap.

Ring Gap Calculator – Instantly Find the Optimal Piston Ring End Gap for Your Engine

Cylinder Bore Diameter * (mm)

Enter your engine's cylinder bore diameter in millimeters.

Engine Type / Application * Select application Street / Mild Performance High Performance / Racing Forced Induction (Turbo / Supercharged) Nitrous Oxide Marine / Endurance

Choose the closest match for your engine's use case.

Ring Location * Select ring location Top Compression Ring Second Compression Ring Oil Control Ring

Select which ring gap you want to calculate.

Output Units Millimeters (mm) Inches (in)

Choose preferred units for the result.

Example Presets:

Honda K20 Street Build
86.00mm bore, Street, Top Ring, mm Big Block Race Engine
100.00mm bore, Race, Top Ring, in Turbo 4-Cyl Build
81.00mm bore, Boosted, Second Ring, mm Nitrous Drag Motor
95.50mm bore, Nitrous, Top Ring, mm Small Marine Engine
75.00mm bore, Marine, Oil Ring, in

Calculate Reset

Calculating optimal ring gap...

Building this calc was hard work - we'd LOVE a coffee (or a beer - we're not picky :))!

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Bore Diameter (mm) The bore diameter refers to the diameter of the cylinder in the engine where the piston moves. It’s a critical parameter as the ring gap depends directly on it.

Ring End Gap (mm) The ring end gap is the distance between the ends of the ring when it is installed in the engine. This parameter is essential for proper thermal expansion during engine operation.

Formula Explanation

The formula used in this calculator is: Ring Gap = 0.004 * Bore Diameter + Ring End Gap

The 0.004 multiplier is a generally accepted standard for calculating the ring gap, ensuring proper clearance during engine operation. It’s crucial to add this to the ring end gap to derive the final gap size.

Using the Ring Gap Calculator

1. Input Values
   • Enter the bore diameter of the engine in millimeters.
   • Input the desired ring end gap value in millimeters.
2. Click Calculate
   • Press the “Calculate” button to compute the ring gap based on the provided values.
3. Observe Result
   • The calculated ring gap value will appear in the “Result” field below the form.

This simple yet vital calculation aids engine builders and mechanics in ensuring the proper fit and functionality of piston rings within an engine’s cylinder.