Words by Tim Adcock - Lead photo by James Drew, product photo courtesy Phenix Industries

During World War II the US military developed a set standard of specifications for the production of flexible steel braided hoses and aluminum hose ends for the purpose of fluid transfer.  This spec, known as “AN” for Army – Navy was established primarily for use on military aircraft. Today this system remains the choice of racers and engine builders, boat riggers and chassis builders as the accepted means of delivery for all vital engine fluid systems.

The contemporary racer / builder can reach for an almost limitless
selection of AN fitting variations to accommodate any plumbing
situation, and with a fair amount of color and coating choices. 
Some companies even offer a complete line of raw fittings allowing
the user to anodize them to a particular custom color theme. However,
in seven decades of development one problem remains the bane of
this ubiquitous system: With just a slight amount of over torque, they
leak.  Not only that, but the solution (additional torque) worsens the
problem thus creating a condition known as, too tight... still leaks. Every
time a fitting is removed and reinstalled the potential for a leak is created.

Of course this is nothing new and is almost an accepted and endearing (to some) attribute of the system.  For others the quest for a good seal and a dry engine bay can be all consuming.  I was recently visiting a highly organized and well-funded Top Fuel team known for their fanatic dedication to the task at hand.  To obtain an effective seal in their AN systems, they are in the practice of lapping in the 37-degree sealing surface using valve grinding compound followed by a thorough cleaning and a careful assembly.  The professional who practices such extreme care is to be admired, but there must be a better way to mitigate the dreaded galling that so often spoils an otherwise excellent fluid system.