108FSR and 105HZ Piston Ring for O.S. Engine OS29203400  [OS29203400]

Replacement piston ring for nitro engines

This piston ring is an RC-scale replacement part intended for use with engines identified as 108FSR and 105HZ, listed under the O.S. Engine OS29203400 part number. The description concentrates on fitment, careful installation, and the ring's purpose within engine maintenance and tuning while avoiding any unverified material claims.

Functionally, a piston ring restores the seal between piston and cylinder to recover compression and reduce blow-by. Before reassembly, confirm the ring profile matches the piston groove and check the end gap against the engine manufacturer's recommended clearance, since an incorrect gap will change compression and idle behavior.

Installation notes: work on a clean bench, apply a light film of suitable glow-engine oil to the ring and piston during assembly, then rotate the crank slowly to confirm free movement before final mounting. Inspect the ring and cylinder for scoring or excessive wear to decide if a ring replacement alone is enough or if further engine work is required.

Tuning role: fitting a new ring is a basic rebuild step that can restore compression consistency and improve throttle response, helping deliver steadier engine behavior during trimming and running sessions.