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

Fit and function overview for piston rings

This piston ring is an RC replacement intended for engines identified as 108FSR and 105HZ, supplied under the O.S. Engine OS29203400 part number. The copy focuses on correct fitment, practical installation advice, and the ring's maintenance role without asserting unverifiable material claims.

The primary function of a piston ring is to seal the piston to the cylinder, restoring compression and reducing blow-by. During installation, confirm that the ring profile matches the piston groove and that the end gap is within the engine manufacturer's recommended limits, since an improper gap will affect compression and idle performance.

Assembly notes: use a clean work surface, apply a light coat of appropriate glow-engine oil to ring and piston while assembling, and rotate the crank by hand to ensure unobstructed movement before final installation. Inspect both ring and cylinder for scoring or excessive wear to determine if further engine repairs are required.

Tuning perspective: installing a new ring is a core service step that can stabilise compression and sharpen throttle response, helping produce more consistent engine behavior on track or during practice.