O.S. Engine OS45060309 Valve Spring Seat for FS-26S, 40S, 48S  [OS45060309]

Valve spring seat for FS series

This valve spring seat is an RC-scale replacement part intended for the O.S. Engine FS-26S, FS-40S and FS-48S engine family named in the model title. Its role is to provide a stable seating surface for valve springs during routine maintenance and tuning of nitro model engines, helping maintain consistent valve action under typical hobby use.

Installation is straightforward for experienced model technicians: remove the cylinder head and verify the valve spring orientation before seating the part. Use light, controlled pressure to avoid deforming the mating surfaces, and inspect the seat for wear or burrs before reassembly. This component supports accurate valve seating which can aid repeatable valve timing adjustments during engine setup.

Because this is an RC-scale accessory, avoid applying vehicle-level torque or workshop methods intended for full-size engines; stick to hobby-grade tools and methods appropriate for model engines.