Fitting the fuel bungs on the main tank. I decided to put the bungs on the inside of the tanks to give me more room in the tank bay for fitting the external fuel lines. Space is at a premium in the bay and this change should buy me at least 3/4 of an inch of extra space to work with.
To make this work I had to modify the threads of the bungs since these were bought commercial bungs threaded from the end opposite the flange. Remember that they are threaded with a tapered NPT thread. First I cleaned the threads well and filled the threads opposite the flange with JB weld and let it cure. I then tapped the threads from the flange side to reverse the taper in the bung. I’m not sure the JB weld was necessary, but it should increase the thread engagement when a fitting is screwed into the bung.