Moki Radial ring exhaust installation

In collaboration with Vogelsang Aeroscale, a no-weld kit was developed for Moki radial engines. Designed to install from the exhaust bend receiver coupling.  The simplest way to add smoke to early Moki radials before the M5 smoke tap ports were implemented.

Just drill a hole and bolt on your smoke nozzle.  

Here we will show the steps involved as well as a few tools needed to install the Moki no-weld smoke nozzle adapter & smoke nozzle kit.  No-weld adapters work with 10-32 threaded atomizing smoke nozzle kits sold separately.  *This late model muffler already has the M5 smoke port and ready for the M5 smoke nozzle kit.  We are going to install the no-weld version next to the M5 smoke port just to show the steps involved.  

This process should be done with the muffler removed from the engine and then cleaned and dried before installing back on the motor. New consumables - Teflon seal rings and copper crush washers are suggested.


Tools needed


  • No-weld drill bit
  • 3/8" wrench
  • Short piece of Tygon tubing
  • Needle nose pliers
  • String or fine wire

Nozzle prep


 Mark the Tygon tubing with a marker and install on nozzle marking the spray direction.  Thread hex nut on to nozzle followed by split lock washer and contoured spacer. Flat side of spacer  against lock washer. 

"Fishing the nut"


After carefully locating placement as not to interfere with intake runner pipe. Remove exhaust bend tube then  drill and deburr hole for nut.  String wire through both holes and install nut nose end first. 

Nut in place


 "Fish" nut into place up the wire until it protrudes from the hole you drilled. 

Ready for nozzle


 Lightly hold the nut with pliers. Carefully remove wire and thread prepped nozzle & components onto nut 1 or 2 turns. Use your reference mark on Tygon tubing. 

Position the nut


 Carefully push the nut back into the muffler while turning the nozzle & nut no more than 1/2 turn while observing the protruding nose. When the nose is at maximum length you have the contoured nut matched to the internal surface of the muffler.  Stop and apply light pressure pulling nut through hole again. 

Set depth & spray direction


Match spacer curvature to match with outside muffler surface. With light pressure holding nut to muffler, thread nozzle into nut 4-5 turns. End with nozzle pointing past receiver inlet and around the muffler circumference. 

Installed & ready for smoke


 Tighten the hex nut and remove the Tygon tubing.  Nozzle is installed and muffler is ready to be installed back on engine.  Be sure to use high temp smoke oil tubing.  See plumbing diagrams for more info.