O.S. Engine PISTON FSa-155 OS42503200 — RC Engine Cylinder Replacement  [OS42503200]

O.S. ENGINES PISTON FSa-155
Price:
£19.68
Brand:
O.S. Engine
Model:
OS42503200
GTIN:
4531028148062
Condition:
Brand New
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Piston duties in rebuilds and tuning

The O.S. Engine PISTON FSa-155 is an RC-scale replacement component intended to fit matching engine cylinder assemblies. The note covers practical fitment, installation cautions, and how the piston relates to engine behaviour without promising any unspecified performance gains.

Use this piston when servicing or rebuilding an engine that shows wear, scoring, or inadequate ring sealing. For replacement in a glow/nitro RC engine, inspect the cylinder wall finish, confirm ring seating, and verify piston orientation and endplay in line with the engine's service manual. This component is not suitable for non-RC or full-size engines.

Installation pointers: prepare a clean workspace, apply light assembly lubrication as the engine manual advises, and rotate the crankshaft by hand to ensure the piston moves freely before completing reassembly. For exact clearances or ring gap figures, rely on the manufacturer documentation.

Specifications

  • Item: PISTON FSa-155
  • Model Number: OS42503200
  • Material: Not specified by manufacturer
  • Compatibility: Refer to O.S. Engine fitment guidance for matching cylinder assemblies

This piston is provided as a serviceable replacement for compatible O.S. engine cylinder assemblies and must be fitted according to the engine maker’s maintenance procedures to achieve correct sealing and reliable operation.

How will this piston affect tuning and engine response?

A correctly fitted replacement can restore consistent sealing and steadier running, which supports predictable tuning. Any change in response depends on the whole engine and the accuracy of installation.

What should I inspect on the cylinder before fitting?

Check the cylinder wall for scoring, measure for out-of-round, and ensure the sleeve and head mating surfaces are clean and undamaged before seating the new piston.

Is this piston compatible with all O.S. engine cylinders?

Compatibility is determined by the specific engine model; consult O.S. Engine fitment guidance to confirm that the PISTON FSa-155 and model OS42503200 match your cylinder assembly.

Any final checks before running the engine?

Verify piston travel is smooth, confirm correct ring seating and clearances, then follow the engine maker’s break-in and run-in procedures before full-throttle use.

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