AN vs NPT info?

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ne57

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Can someone direct me to where online I can learn about AN and NPT systems?

I need to know how the two systems relate. I will be doing a remote elec water pump and I'm confused about what size water hoses are compatible with what size AN and what size NPT fittings I need to use. There's no 'kit' for my application so I need to design it, which means first I have to know what I'm doing.

Specifically at the moment I'm trying to figure out what size NPT fitting I need to put in the block/heads to accept a -12AN fitting and appropriate hose and not have a restriction from reducers that don't flow enough. My front cover has ears that block off the inlet ports so I need to work from there backwards I think. Meziere suggested -12 as the size that's right for my cooling needs but his block adapter for a big block won't fit my 1stgen hemi so I'll have to fab something up. I was thinking either drill and tap the ears for NPT and then the AN fit to that...or maybe use weld in bungs and put a -12AN male fitting right on the aluminum cover. Or do i even NEED AN fittings? can I run regular hose to barb fittings? I like the look and security of braided line but I'm open to getting the job done easier/cheaper too.

Thanks

For the heads I have a set of plates with 1/2NPT female, I'm not sure that's going to provide enough flow.
 

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I would say go on Summit's site and check out the AN to NPT fittings they have I believe you can get 12 AN in up to 1 1/4" NPT. I would drill and tap the ears on the cover if it is thick enough. I would definitely go with AN hose and fittings. You can also get AN in 16 and 20.
 
Not sure but it was explained to me each an was a 1/16 so 12 an would be 3/4
 
Maybe this will help some too?
 

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You might look at Russell and Aeroquip, both offer a black smooth hose with a rubber appearance, that is good for everything but P/S and brakes, that uses a barb style of fitting, that litterally pushes on and you are done. Hose is available in ugly blue or black.
It is less expensive then traditional AN and braided to boot.
Many of the adapters from AN to NPT are sold only in red and blue. If that does not work with color theme, there are tricks out there to remove the anodizing, leaving a natural aluminum finish.

http://www.russellperformance.com/mc/hose/twist-lok.shtml

634103_lg.jpg

chart_lg.jpg
 
NPT is pipe thread, is tapered, and is "called out" by the NOMINAL inside dia, which is not really true. In other words, 3/8" NPT is "roughly" 3/8 ID. If you are trying to figure out what actual size pipe thread you are dealing with,

This page:

http://www.plumbingsupply.com/pipethreadsizing.html

has a chart showing pipe thread OD sizes

Pipe thread is also often referred to as #6 for 3/8, as example. The "number" sizes are simply a way to relate in 16's of an inch, mainly for shelf stocking and inventory.

1/8 pipe no2, 1/4 pipe no4, etc, etc

Also, do not confuse AN sometimes called by hydraulics guys as JIC, which has a 37* flare angle,

with SAE, your common brass fittings, which has a 45* flare angle. some sizes of the two will interchange, but at least no6 and no12 will not screw together.

In other words, some sizes of the two series, AN (JIC) and SAE will actually screw together, and some brands sell them interchangeably as to the sizes that WILL fit together.
 
Hey thanks very much guys. I found the tutorial videos at anplumbing really useful...takes all the mystery out of making hoses. And the orderly way the sytems parts are laid out makes it easy to see what is what. I had previously been to suimmit and the parts were kind of randomly listed, which made it hard to get the feel for how the whole deal works. If you know precisely what you want its OK but if you're a neophyte like me its nice to have some instruction and an easy selection process.


So it looks like to me that weld in bungs are what I should use on the front cover and head plates. NPT taps and reamers ain't cheap for a one shot deal.

Thanks much again! FABO ROCKS.
 
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