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

Valve Pin Set Screw Overview

This O.S. Engine part is presented as a valve pin set screw for the 90RSR-M designation, intended as a direct RC-scale engine accessory for valve retention and related maintenance tasks. The listing identifies the component by model number only, so use this part when replacing or inspecting the valve mechanism on engines that reference 90RSR-M in their service documentation.

Functionally, a valve pin set screw secures valve pins and helps maintain valve timing integrity after routine disassembly or rebuilds. In practical workshop use, confirm alignment of the valve train and thread engagement before final tightening, avoid cross-threading, and verify movement after reassembly to ensure valves operate freely.

For tuning or rebuild cycles, this screw is a small but necessary part in valve maintenance routines. When servicing the cylinder head or cam assembly, treat the screw as a torque-sensitive fastener: start threads by hand, check seating, and re-check clearances once the engine is back together and run-in procedures are performed.