The Piston Crevice Volume calculator computes the crevice volume (Volc) of a 
Piston Ring Crevice combustion engine cylinder as a function the bore diameter(bD), piston diameter (pD) and the top ring depth (rD).
INSTRUCTIONS: Choose your preferred units, the default is inches and mils, and enter the following:
- (bD) Bore Diameter
- (pD) Piston Diameter
- (rD) Top ring depth
| Inch Equivalences | |||
| Fraction | Decimal | Mils | |
| 1/16th | 0.0625 | 62.5 | |
| 1/32th | 0.03125 | 31.25 | |
| 1/64th | 0.015625 | 15.625 | |
Cylinder Crevice Volume: The volume is computed in cubic inches. However, the can be automatically converted to other volume units (e.g. cubic centimeters aka CCs) via the pull-down menu.
The Math
Engine Math (Baechtel) and I disagree on this equation. Engine Math takes the difference of the diameters (bore and piston), multiplies that difference by the circumference of the bore to create the surface area of the crevice and then multiplies that surface area by the depth to the top ring to get the volume. The surface area of that equation is geometrically wrong. Fortunately these crevice volumes don't affect much. But the mathematician in me can't let it sit. The correct formula for the crevice surface area is the difference between the two circle areas defined by the bore diameter and the piston diameter, using PI*r2 where r is half of the respective diameters. THEN multiply the correct surface area by the crevice depth from the deck to the top piston ring. I'm sure Baechtel's answer is probably good enough, but this is more correct.
Combustion Engine Calculators
- Cylinder Bore Diameter based on the engine displacement, number of cylinders and the stroke length.
- Bore Stroke Ratio based on the diameter of the bore and the length of the stroke.
- Combustion Ratio base on the minimum and maximum displacements of the cylinder at the beginning (1-Induction) and compressed (3-Power) portions of the combustion cycle
- Displacement Ratio based on the volumes at the beginning and end of the stroke.
- Rod and Stroke Length Ratio base on the two lengths.
- Stroke Length based on the total engine displacement, number of cylinders and the bore.
- Piston Position based on the crank angle, crank radius, and rod length.
- Total Volume (displacement) of a Combustion Engine based on the bore, stroke and number of cylinders.
- Volume (displacement) of a Engine Cylinder based on the bore and stroke.
- Volume (displacement) of an Engine with an Overbore based on the stroke, bore, overbore and number of cylinders.
- Equivalent Volume of a Rotary Engine based on the swept volume and number of pistons.
- Compressed Volume of a Cylinder when the piston is at the end of the stroke and the chamber is at its smallest (and most compressed) volume, based on the chamber, deck, crevice, chamfer, gasket, valve relief and dome/dish volumes. This is the second volume (V2) in the Compression Ratio calculation.
- Volume of a Gasket based on the inner and outer diameters and the gasket's thickness.
- Volume of a Cylinder Deck based on the deck height and the bore.
- Volume of a Cylinder Crevice based on the piston diameter, cylinder bore and the crevice height.
- Volume of a Cylinder Chamfer based on the cylinder diameter and the chamfer height and width.
- Piston Speed (mean) based on stroke length and RPMs.
- Max Piston Speed based on stroke length and RPMs
- RPMs based on desired piston speed and stroke length.
Other Automotive Calculators
- Camber Angle
- Camber Offset
- Breakover angle - Ground clearance between axles
- Approach angle - Ground clearance in front of or behind vehicle.
- Belt Length
- Belt Speed.
- Pulley RPMs
- 2nd Pulley RPMs
- 2nd Pulley Diameter
- RPM of 4th pulley on three shafts
- 2nd Gear RPM