All QualCast valve seat inserts have a finished ID and geometry on the lead-in edge to ease the press fit. QualCast uses a variety of alloys to suit the applications listed in the catalog.
QualCast "N" Series seat inserts are manufactured using a non-magnetic nickel based alloy which provides high temperature hardness and corrosion resistance. QualCast "S" series seat inserts are manufactured using a cobalt based alloy.
20-Prefix denotes the four digit number is the estimate cutter size. The actual OD includes a press fit for a cast iron head of between .0045" and .0060" depending on size. For example, 20-1562-1 suggests the use of 1-9/16" cutter and allows for .0045" press fit. Actual OD is 1.5670".
21-Prefix is specifically for aluminum cylinder heads. The part number also includes the estimated cutter size and allows for .007" press fit. For example, 21-1625-59 suggests the use of a 1-5/8" cutter and allows for .007" press fit. Actual OD is 1.6320".
22-Prefix denotes the part number is the exact OD. Used for factory installed seats. For example: 22-2006-1 shows the actual OD of 2.006".