Valve Seat Servicing
- Check valve seat for damage or wear. Replace or rework seat, as necessary. If reworking seat, check valve guide first. Make proper replacement, if required, then check seat for necessary corrections.
- Recondition valve seat with grinder or cutter to specified contact width. After rework, valve and seat should be lapped with compound.
- Valve seat sink (wear of seat inward allowing valve to seat too deep in head) must be checked by measuring installed height of spring between the spring seat and retainer with all spring components installed.
- Standard dimension is 1.590" (40.4 mm) with an additional wear limit of .039" (1.0 mm). Replace valve seat if beyond limit.
- To remove valve seat, thin down with a cutter. Machine seat bore to proper size for replacement seat. Heat head to approximately 480°F (250°C) and press in oversize seat.
- Replacement seats are available in .012" (.305 mm) and .024" (.610 mm) oversizes, marked "30" and "60" respectively. After installing, machine valve seat to specifications.