O.S. Engine OS44303400 Piston Ring FSa-72  [OS44303400]

Piston ring for RC nitro engines

This piston ring is an RC-scale replacement part intended for cylinder and piston assemblies produced by O.S. Engine. It serves the core function of sealing the combustion chamber on nitro model engines, helping maintain compression and consistent engine performance during running and tuning sessions.

Installation notes: inspect the piston and cylinder for wear before fitting a new ring, orient the ring gap per the engine manual, fit the ring gently onto the piston without forcing or deforming it, and ensure the piston slides freely in the cylinder before final reassembly.

Tuning role: a correctly seated piston ring contributes to repeatable compression and oil control, which affects throttle response and idle stability; during engine tuning, verify compression readings and adjust needle settings only after confirming the ring and piston fit are correct.