M12 Exhaust Header Pipe Nut Compatible with FS120SII FT120 FT160 FF320 - O.S. Engine OS45526400  [OS45526400]

Role of the M12 Header Nut in Tuning

This M12 exhaust header pipe nut provides the threaded clamp that fastens the exhaust header to the engine flange and the tuned pipe. As an OEM-fit style part for RC nitro engines, it keeps the outlet sealed and positioned through the usual heat and vibration of model use.

Compatibility is limited to the model codes listed in the product title; confirm your engine model before installation. Because the nut secures the flange, its position has a direct effect on pipe alignment and the resulting backpressure, which is a factor in throttle response and tuning adjustments.

Installation notes: always start the threads by hand to avoid cross-threading, then use the correct tool and apply gentle torque to seat the nut without overstressing the flange. Check the fastener after initial running and after aggressive sessions since vibration and heat can loosen small fasteners.

Tuning advice: when trimming or swapping a tuned pipe, loosen the header nut only as much as needed to reposition the pipe, confirm alignment, and then retorque to restore a consistent seal and repeatable performance characteristics.