PART NUMBERING & INTERFERENCE FITS
All Imperial Universal valve seat inserts are dimension with relevant interference built into the outside diameter. This will vary from 0.0045” for small diameters to 0.006” for large diameters (refer to numerical listing at rear of catalogue for detail). Always allow additional interference for aluminium heads.
e.g. KB1562-1A has a nominal O.D. of 1.562” (1-9/16). Actual O.D. is 1.567” for use with 1-9/16 cutter.
All other valve seat inserts are dimensioned with EXACT outside diameter and have no interference built into the insert. Typically, these are Metric Universal and Heavy Duty references. All such part numbers are suffixed with the letter X (i.e. eXact).
e.g. KB1496X-1A has exact O.D. of 1.496” (38mm). Actual O.D. is 38mm for use with metric or adjustable cutters.
For material selection, choose our part number with suffix “A” or “B” according to your requirement.
"A" = Hi-Nickel Superalloy
"B" = Lo-Nickel Chromalloy
“A” material is a high nickel, non-magnetic, non-corrosive superalloy and is suggested in applications where extreme heat applies eg. LPG, natural gas, propane, turbo or supercharged, heavy duty diesel etc.