C630 bronze guides
C630 is a blend of copper, nickel, and aluminum.
The high copper content gives excellent thermal
qualities, the nickel makes the guide tough and
wear resistant, and the aluminum brings work
hardening characteristics. This bronze alloy
allows for tighter clearances than other materials,
creating better valve and seat sealing, as well as
superior oil control. The expansion qualities of
C630 bronze make it especially compatible with
aluminum cylinder heads.
