AN taps

[baxsom]

i cant find these anywhere
i am tapping my stock fuel rail to accept 6an fittings
or at least i want to
but i cant locate AN sized taps only npt
i have tried Sears. Ace hardware, and places like that but cant find anything

for those that have already tapped their rails
where did you find yours

 

[aleccolin]

There's a reason they don't make AN thread taps...it's a two sided system. MEANING that for an AN connection to seal, it requires the seat manufactured into the fitting. National Pipe Thread is a compression fitting, it seals itself. Your best bet, use an NPT tap and a (readily available) NPT to AN fitting adapter.

Will the bolt-on AN fuel rail adapter not fit the rail on a 420a? Cause that would be an even better way to go.

 

[baxsom]

you can find 6an bolt on adapters
but the small tube that goes from the inlet to the actual rail is still 4an sized
its better to just drill and tap the rails themselves and cap off both the 4an test port and the inlet

then you have a true 6an system

i guess i could use a 3/8 to 6an male to male adapter and use the npt side into the rail
then run weld bead around the edges
i didnt even think of that actually
they are the same ID

 

[superdave013]

You need a 9/16-18 tap for a -6 AN thread. Kiss it real light with a counter sink after you tap it so the o ring has a seat.
AN threads look much better then NPT as the fitting threads all the way in and seat on the flange / o ring. NPT threads are an interferance fit so you always see some threads hanging out there.