Where to Measure your KB Piston for Proper Piston-to-Wall Clearance



We always receive a lot of questions on the proper place to measure a KB Piston for correct piston-to-wall clearance. KB Pistons are measured at the bottom of the balance pad for both the hypereutectic and forged applications. Below is a diagram showing the proper place to measure your KB Piston to get the correct piston-to-wall clearance.




Piston-to-wall clearance will be dependent on your application. See the clearance chart below for minimum and realistic maximum loose fit clearance for KB Pistons.




AUTO APPLICATIONS
APPLICATION Hypereutectic Forging
Ring End Gap Factor Suggested Piston To Wall Clearance Ring End Gap Factor Suggested Piston To Wall Clearance
Bore To 4.100" 4.100" & up Bore To 4.100" 4.100" & up
Street - Normally Aspirated .0065" .0015" - .0020" .0020" - .0025" .0040" .0035" - .0045" .0045" - .0055"
Street - Towing .0080" .0015" - .0020" .0020" - .0025" .0045" .0040" - .0050" .0050" - .0060"
Street - Nitrous or Supercharged .0080" .0020" - .0025" .0025" - .0035" .0050" .0045" - .0055" .0055" - .0065"
Circle Track - 2 BBL or Restrictor/Gas .0070" .0015" - .0045" .0020" - .0050" .0040" .0040" - .0050" .0055" - .0065"
Circle Track - Unrestricted .0080" .0025" - .0045" .0030" - .0045" .0040" .0045" - .0065" .0055" - .0075"
Circle Track - Alcohol Injection .0060" .0025" - .0045" .0025" - .0050" .0040" .0045" - .0065" .0055" - .0075"
Circle Track - Alcohol Carbureted .0080" .0030" - .0045" .0030" - .0050" .0045" .0050" - .0070" .0060" - .0080"
Drag - Gasoline .0075" .0015" - .0045" .0020" - .0045" .0040" .0050" - .0070" .0060" - .0080"
Drag - Alcohol .0065" .0015" - .0045" .0020" - .0045" .0040" .0040" - .0070" .0050" - .0080"
Drag - Supercharged or Nitrous Gas .0095" .0020" - .0045" .0025" - .0050" .0050" .0060" - .0090" .0070" - .0100"
Drag - Supercharged Alcohol .0085" .0015" - .0045" .0025" - .0045" .0050" .0050" - .0070" .0060" - .0080"
Drag - Supercharged Fuel .0115" .0030" - .0050" .0035" - .0055" .0060" .0070" - .0100" .0080" - .0110"
Marine - Normally Aspirated .0080" .0030" - .0045" .0035" - .0050" .0040" .0045" - .0060" .0055" - .0070"
Marine - Supercharged .0090" .0030" - .0045" .0035" - .0050" .0045" .0055" - .0070" .0065" - .0080"
Air Cooled Baja .0075" .0030" - .0045" .0035" - .0050" .0040" .0050" - .0070" .0060" - .0080"
Propane .0065" .0015" - .0045" .0020" - .0045" .0040" .0035" - .0070" .0045" - .0080"
Supercharged Monster Truck / Mudbog .0090" .0025" - .0045" .0030" - .0050" .0060" .0080" - .0100" .0090" - .0110"


MOTORCYCLE APPLICATIONS
APPLICATION
Ring End Gap Factor Suggested Piston To Wall Clearance
ALUMINUM CAST IRON
Street - Normally Aspirated .0065" .00075" - .0015" .0010" - .0015"
Street - Nitrous or Supercharged .0080" .0015" - .0025" .0020" - .0025"
Flat Track - Gasoline .0080" .0010" - .0020" .0015" - .0025"
Flat Track - Alcohol .0060" .0010" - .0020" .0015" - .0025"
Drag - Gasoline .0075" .0010" - .0020" .0015" - .0025"
Drag - Alcohol .0065" .0010" - .0020" .0015" - .0025"
Drag - Supercharged or Nitrous Gas .0095" .0015" - .0030" .0020" - .0030"
Drag - Supercharged Alcohol .0085" .0010" - .0020" .0015" - .0025"
Drag - Supercharged Fuel .0115" .0020" - .0030" .0025" - .0035"








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