Hastings 2C Piston Rings often have sizing confusion, due to size indication on the box. This is a question we get quite a bit. Illustrated in the corresponding image is correct sizing, for both standard and oversized rings. For instance all B-Series rings 81mm-82mm will be noted on the box as 81mm. The oversize is lised in the part number on the side if the box 2C-4666 for standard size, 2C-4666-10 for +.25mm, 2C-4666-20 +.5mm, 2C-4666-30 +.75mm and 2C-4666-40 for 1mm oversized.
This is the same for all D-Series, B-Series, K20 and K24 piston rings to thier corrasponding part number and size.
When choosing the best ring gap for your engine you must consider several important factors, such as Boost, NA, engine use (Drag, Road Racing, Circle track or street) or fuel used. Many customers believe that they must follow OEM Honda specs and that is not always correct for your application or build. Always use OEM gaps if you are using OEM pistons and original Honda rings. Every ring Manufacturer generally has their own recommended gap sizes. (Note) Turbo gap specs listed below are stated at approximately 20 PSI of boost or less. For more that 20 PSI of boost add .001” more gap to the First and Second ring for every additional 8 PSI of boost.
HASTINGS 2C SERIES HIGH TENSION RINGS
TURBO TOP .018”-.020” SECOND .022-.024”
NATURALLY ASPIRATED TOP .016”-.018” SECOND .020”-.022”
STREET USE: USE THE SAME AS NATURALLY ASPIRATED BUT CLOSEST TO THE SMALLEST NUMBER
DO NOT TOUCH OIL CONTROL RING OR RAILS
If you are unsure of what your specific needs require, please contact us with your specific engine use and fuel you will be using for a custom ring gap recommendation.
Note: If you are unable to achieve specifications. Please check your bore size and Piston to Wall Clearance. Typically that would mean that sizing is off. The bore was cut too large or the cylinder is either worn or out of round. Make sure to check proper PTW with your piston manufacturer. If using OEM Honda or Nippon Racing Pistons your PTW Clearance should be .0013 .