Please explain In detail the difference b'n AN fittings and metric
 

I'm sure that other newbs could benifit from this aswell.

I was told by a domestic musclehead shop that you couldn't use pipe thread sealant on AN fittings. Is there any truth In that? He said It will f#%^ It up. I dunno.

When installing A/N fittings onto hose, you need to use a special assembly lube. As far as threading fittings together, Earl's fittings won't seal with thread sealant, you need an o-ring, which Earl's fittings come with anyway.

In general, you shouldn't use any sealant on AN flare fittings -- they don't need it. For AN port connections (FPR), use an o-ring and no sealant.

-Max

Hmmm, I bought some AN Russels fittings for my fpr and the guy at the shop said you dont use Orings with the Russels, he said for me to just put some fuel safe teflon tape on it....was he wrong? There isnt any recessed surface on the fitting or the fpr for a oring to seat

Hmmm, I bought some AN Russels fittings for my fpr and the guy at the shop said you dont use Orings with the Russels, he said for me to just put some fuel safe teflon tape on it....was he wrong? There isnt any recessed surface on the fitting or the fpr for a oring to seat

I don't think AN port connections (like you commonly find on FPRs) are tapered, so you need the o-ring to seal it. Most of the time, people use a male-to-male flare fitting (straight threads) with an o-ring to seal it on the FPR body. Tape or sealant works with tapered connections, but I don't think that is the case with the AN ports on FPRs. However, there may be some variation out there -- perhaps your FPR has tapered pipe thread ports.

-Max

Speaking of tapered threads, I just tried some Hylomar as a thread sealant today. I'll get to see how well it works soon.

when using an "AN" fitting or JIC as it can also be called with a 37* angle on the end... that is what seals it.
pipe thread is tappered and requires a seal tape.
fuel port threads are the same as AN threads but without the 37* "tip" hence the need for the O-ring since the 37* is what seals an "AN" thread.... for a -6 for instance, it uses the same 9/16 -18 thread that the JIC/AN fitting uses, but does not have the 37* tip...
wow, thats hard to explain to someone... LOL

bypass FI regulators usualy use an "AN" thread and carb regulators usualy use a pipe thread. i say usualy in both cases because i am not aware of any varience on either.

Re: Please explain In detail the difference b'n AN fittings and metric
 

not sure about "Fing it up" but there is no need for it.... read my other responce above. hopefuly i explained it ok.

so its the 37* angle threads that makes it to where you cant go from AN to pipe thread then right?

DAMN, this sucks cause now I'm going to have to pull my fpr apart to throw some orings in there. I have a Aeromotive fuel pressure regulator wtih some Russel AN fittings screwed in the side of it and all I used was teflon tape.

STEPHEN

The 37 degrees thing has nothing to do with the threads. I think threads on AN fittings are always straight (not tapered). The 37 degree part is the flare where AN flare fittings seal. However, AN port connections (as opposed to AN flare connections) are different -- there is no flare. So you have to use an o-ring to seal it. Tape or sealant on the threads is pointless for any AN fittings (port or flare).

Pipe fittings have tapered threads, so you use tape or sealant to seal the connection.

Bottom line: don't use tape or sealant on any AN connections. Your FPR probably has AN connections. Use an o-ring to seal on the FPR body. The other side will be a flare fitting and needs nothing else to seal.

I used male-to-male AN fittings (one piece of aluminum with male AN flare connections on both sides) to connect to my FPR. The FPR doesn't have the flare to seal against my fitting, so I used o-rings to seal the connection on the FPR side.

-Max

I've been told by various companies to use Teflon PASTE and not tape on the threads of AN fittings. The tape can do wierd things, apparently, if it comes off into the fuel stream and clogs the injectors.

FPR's get O-Rings, everything else should get teflon paste. That's been my experience.

~Brad

what companies told you this? i hope you misunderstood them. AN threads do NOT require any additional sealing. reread my prior reply, and max's reply.

It was a few shops in Northern VA and MD, when I was driving my Probe GT. They recommended it so that the fittings would go together farther, as a lubricant so I could get them tighter, not as a sealant :-P

That's what the teflon crap is for, it's not a sealant, it just lets you tighten it farther because it lubes up the threads. :pimp:

~Brad

So since they are sealed from that tapered edge that means its VERY important for them to be screwed 100% of the way in doesnt it?

I had a few fittings that I couldnt get screwed all the way to the bottom of the threads.....should I worry about this?

Also, I have a KG fuel rail and I couldnt get the fitting all the way in the bottom of it, in addition since the rail doesnt have that flared part inside do I need to use a oring there?

STEPHEN

So since they are sealed from that tapered edge that means its VERY important for them to be screwed 100% of the way in doesnt it?

I had a few fittings that I couldnt get screwed all the way to the bottom of the threads.....should I worry about this?

Also, I have a KG fuel rail and I couldnt get the fitting all the way in the bottom of it, in addition since the rail doesnt have that flared part inside do I need to use a oring there?

STEPHEN

So since they are sealed from that tapered edge that means its VERY important for them to be screwed 100% of the way in doesnt it?

I had a few fittings that I couldnt get screwed all the way to the bottom of the threads.....should I worry about this?

Also, I have a KG fuel rail and I couldnt get the fitting all the way in the bottom of it, in addition since the rail doesnt have that flared part inside do I need to use a oring there?

STEPHEN

I'm not the expert here. I'd guess they'll be ok, just keep a close eye on them. Use common sense, if something *seems* wrong, and you have time to fix it, give it a shot. If you can get it on there farther, then it'll only make it better, unless you smurf something up else in the process.

Someone at the beginning of the thread mentioned using a special lube...which is the teflon paste i mentioned in my post...not a thread locker, but a make-the-threads-go-on-farther typa thing.

~Brad

Wow, lots of misinformed people out there giving out bad advice.

AN fittings do have straight machine threads, they also have a 37* cone that does the sealing, never use tape or sealant on them. Where an AN fitting goes into a boss you would use an oring to seal the joint. This applies to AN fittings with machine threads on the boss ends, not an AN to pipe adapter fitting.

Pipe fittings have tapered threads and require some sort of sealant tape or sealant to effect a seal. Remember some AN fittings have pipe threads on one side and are an adapter fitting.

Standard automotive double flare fittings (i.e. brake lines) use a 45* cone to seal and also do not require any sealant/tape.

Theres also metric fittings (like front and rear cover bosses) that use a metric machine thread, and BSP (British Standard Pipe), but AN and Pipe are the most common you'll see.

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