Crankcase Housing for 61RX-H/HGL Engines - O.S. Engine OS27921000  [OS27921000]

Fit notes and part function

This replacement crankcase is catalogued as O.S. Engine OS27921000 and is intended for use with the 61RX-H and HGL engine codes shown in the product title. The housing locates the crankshaft and bearing set, preserving internal alignment throughout an engine rebuild.

Use this part only with the model codes listed; it is designed for hobby-grade nitro RC engines. Before installing a new crankcase, clean the contact faces thoroughly, confirm the bearing seat condition, and check any seal or gasket surfaces to ensure a proper assembly.

During tuning, correct crankcase alignment contributes to stable crankshaft runout and correct bearing preload, which can affect idle trim and throttle response. Always trial-fit the crankpin and bearings to confirm compatibility prior to final installation.

This component is provided as a direct replacement housing for the engine references shown, intended to restore internal geometry and crankshaft alignment during maintenance and rebuilds.