25XZ Internal Head Service Part - OS22854100 for O.S. Engine  [OS22854100]

Identified by part number OS22854100, this inner head fits the O.S. Engine 25XZ family and functions as a replacement internal head component. It is intended for repairing worn or damaged head assemblies on RC-scale nitro engines.

When visual checks reveal seal failure, warping, or cracking in the head area of a 25XZ engine, this inner head provides a targeted repair option. Replacing the inner head restores proper sealing and serviceability without disposing of the complete engine.

Installation notes are deliberately general: remove the head per the service manual, inspect and replace gaskets and O-rings as needed, and refit using the manufacturer recommended torque and thread engagement. Confirm sealing integrity and follow run-in procedures advised by the engine maker before normal use.

In tuning and routine maintenance this inner head is treated as a consumable spare, enabling bench repairs, head swaps during rebuilds, and scheduled replacement to keep engines performing consistently.