25XZ Internal Head Service Part OS22854100 compatible with O.S. Engine  [OS22854100]

Part OS22854100 is an inner head manufactured to suit O.S. Engine 25XZ series units as a service replacement. It is used to replace damaged or worn upper-end head elements on RC nitro engines.

Deploy this inner head when inspections show leakage, cracking, or other head assembly issues in a 25XZ-series engine. Swapping the inner head can resolve sealing issues and return the engine to operational condition without replacing the whole unit.

Follow the engine's service manual for disassembly and reassembly: inspect and replace gaskets and O-rings, clean sealing faces, and tighten fasteners to the specified torque and engagement. Confirm sealing and complete any run-in steps recommended by the engine maker prior to regular use.

As a consumable spare, the inner head is suitable for bench repairs, head swaps during rebuilds, and routine servicing to maintain consistent engine performance over time.