AN fittings and your Weber 32/36

[Dudeland]

I searched all over the forum and never found the answer, so I thought I would document it here.  The input on a Weber 32/36 (with a threaded fitting on the end) is a 1/8 -27 NPT fitting.  How do I know... i spent some time at Home Depot and the at Canadian Tire today going through the dies and taps. I happened to have a spare lid off an old junk carb that I could use.  The interesting part is that the threaded bore seems to be tapered quickly, so if you put in a 1/8" pipe fitting you get two threads in and then it starts to bind... but if you match the bolt to a die, it goes on perfectly. 

 

So if you are running AN style fittings for your fuel delivery hose to your Weber, you need to get a 1/8" to -6 or -4 AN line.   I will post pics once I have my line installed.  As always use Teflon paste, not tape, to seal between the 1/8 fitting and the carb (if you feel you need to). 

 

 

 

 

 

 

[02Les]

Assuming the carb was manufactured in Europe, I would have thought the thread would be 1/8" bspt.

Finding NPT fittings overseas can be as rare as rocking horse droppings.

[Simeon]

BSP will be correct. The 'few turns and then stops' is the common sign between the two. 

 

More info:

 

https://www.valvesonline.com.au/references/threads/

 

 

Edited November 15, 2017 by Simeon

[Dudeland]

F'n shitty.  How the heck do I get a 1/8 BSP to 6an fitting? And why did the die fit on the bolt?

[Dudeland]

Ok I found one in Japan.  We will see if it fits when I get it. 

 

[tahoedon]

Pegasus Racing has a 1/8 bsp male to 4AN male, part no. 3230-2-4AN

['76mintgrün'02]

33 minutes ago, Dudeland said:

why did the die fit on the bolt?

(( I am waiting for the punchline ))

 

" BSPT (British Standard Pipe Thread) is similar to NPT except for one important difference. The angle across the flanks of threads (if you sliced the fitting in half long-ways and measured the angle from root to crest to root) is 55 degrees instead of 60 degrees as it is for NPT. "

[Dudeland]

I know I just looked up the same article.  That is why the bolt would go into the Die, Anyway. I learned something new today.  I wonder if anyone else is looking for this info?  Maybe I should corner the market LOL!!!!!

[TobyB]

BSPT, Tom, isn't that British Standard Pipe Taper?

 

Like NPT is National Pipe Taper?

 

t

 

[Simeon]

4 minutes ago, TobyB said:

BSPT, Tom, isn't that British Standard Pipe Taper?

 

Like NPT is National Pipe Taper?

 

t

 

 

It is. British Standard Pipe (Taper or straight) was chosen as the 'European standard' and even erroneously called a metric pipe thread. In Australia we even have BSP threads applied to metric sized pipes (internal diameter) - very confusing 

[Dudeland]

I once read that the thread was some "crazy metric thread" but I dismissed it as nonsense.  Now it makes a little more sense.  I just wish I didn't have to wait until Dec to get a fitting.  

[jireland2002]

Just run a 1/8npt tap into the hole and you're good.  If you are going to use an aluminum AN fitting you must support the braided hose or it's weight will fatigue the fitting and it will break and probably set the car on fire.  It is actually better to just use a hose barb and rubber fuel hose.

[Healey3000]

And then there's BSW - Whitworth...

[Dudeland]

Crazy... I don't know what other experiences are with running a 1/8 NPT tap, but from what I can find BPT has a different pitch than NPT.  I have an -6 to barb that I will run until I can get the BPT to -6. 

 

NPT is 27, BPT is 28. 

 

 

[Simeon]

Having spent a bit of time googling it the only references to the threads on Weber inlets are M12 for the banjo inlets on side drafts and down drafts such as the IDF and M10. These are all shown as parallel threads with a crush washer. Could it be an M10?