FS120SII FT120 FT160 FF320 M12 Exhaust Nut OS45526400 by O.S. Engine  [OS45526400]

Exhaust Header Nut — Installation and Purpose

This M12 exhaust header pipe nut is supplied as an OEM-fit style component for RC nitro engines. It fastens the exhaust header to the engine flange and tuned pipe, helping preserve a sealed joint and correct alignment through normal heat and vibration encountered in model use.

Compatibility is limited to the model codes listed in the product title; confirm your engine model before installation. The nut's mechanical job is simple but important: clamp the header flange so the exhaust pipe stays in its intended position, which can affect backpressure and tuning outcomes.

Installation notes: begin threading by hand to prevent cross-threading, then use the right size wrench and apply modest torque to seat without stressing the flange. Check the nut after the break-in period and again after hard sessions, since vibration and heat can loosen fasteners on nitro engines.

Practical maintenance tip: when you need to service or swap a tuned pipe, loosen the header nut only enough to reposition the pipe, recheck alignment and retorque to restore a consistent seal and predictable performance.