O.S. Engine OS29203400 piston ring for 108FSR and 105HZ engines  [OS29203400]

Piston ring for glow 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 text focuses on fit, installation considerations, and the ring's role within engine maintenance and tuning without asserting unverified material details.

Functionally, a piston ring restores the seal between piston and cylinder to recover compression and reduce blow-by. When fitting a replacement ring, confirm the ring profile matches the piston groove and that the end gap is within the engine manufacturer's recommended clearance before reassembly, as incorrect gap can affect compression and idle behavior.

Installation notes: work on a clean bench, lightly lubricate the ring and piston with appropriate glow-engine oil during assembly, and rotate the crank gently to verify free movement before completing the mount. Routine inspection of the ring and cylinder for scoring or wear helps determine whether a new ring alone is sufficient or if further engine work is needed.

Tuning role: replacing a worn ring is a basic maintenance step that can improve compression consistency and throttle response, contributing to more predictable engine behavior during setup and trimming sessions at the track.