90RSR-M Valve Pin Set Screw OS29116208 by O.S. Engine  [OS29116208]

Overview of Valve Retention Screw

This O.S. Engine component is presented as the valve pin set screw for the 90RSR-M model reference, intended as a direct service part for RC engine valve retention and related maintenance. Fit this screw when a parts list or service diagram for 90RSR-M specifies replacement of the valve pin fastener.

The set screw's role is to lock valve pins in place so valve timing remains consistent after disassembly or rebuilds. In practical servicing, check for correct valve train alignment and thread engagement before applying final torque, take care to avoid cross-threading, and confirm valve freedom after the engine is reassembled.

During rebuilds and tuning sessions this tiny fastener is essential to valve servicing routines. When working on the head or cam, treat the fastener cautiously: hand-start the thread, ensure proper seating, and re-evaluate clearances after the engine has been run.