Quick carb question, 2g fuel inlet thread size

tenxal

Well Known Member
Ozzie is correct....7/8"-20 thread.

None of those you linked are what you need. The easiest solution is to drill & tap the stock inlet nuts to 5/8"-20 and use the commonly available banjo size.
 
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neilswheels

Well Known Member
Little update, realised today that I’ve been barking up the wrong tree. This is what I’ve got, as you can see, tube nuts screwing into an adapter/reducer on the carb. The thread on the tube nut measures 1/2 inch. I’m assuming that this is a pipe set from show cars or similar, so anyone know what the thread is? Thankd
 

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ozzie7

Well Known Member
This is the size for the fitting on the carb.
7/8"-20 x 1/2"-20 = Inlet Fitting
If you unscrew the fitting from the carb, you should find the bronze filter there.

Keep in mind that the 1/2"-20 fitting on the fuel line is a flare fitting.
It's not a pipe thread.... so if you're switching to banjo connectors, be certain what you need.
You may need to change the Inlet fitting depending on how you are setting up the fuel line.

Check out this link to see a lot of the different types/sizes available... Quadrajet Parts
 
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neilswheels

Well Known Member
Thanks. Yep, bronze filter and a spring behind that. I thought I’d cracked it, went to a speed shop with the back carb, and it appeared that banjo fittings for a Strindberg fitted, so I bought them. They arrived today, I excitedly went to screw them in, and it will barely go in the front carb 2 threads, bummed, more head scratching to be done.
 

neilswheels

Well Known Member
Little update, after trying to find a unf thread gauge in Blighty, I thought ide try one of the othe banjo bolts, and it fits!! So, one dodgie thread, the other two are fine. Thanks for your input, much appreciated.
 

La Hot Rods

Well Seasoned Member
Supporting Member 15
Little update, after trying to find a unf thread gauge in Blighty, I thought ide try one of the othe banjo bolts, and it fits!! So, one dodgie thread, the other two are fine. Thanks for your input, much appreciated.

Does this banjo bolt thread into the filter fitting or does it thread into the carburetor?
 

neilswheels

Well Known Member
So here’s a pic of the type of fitting I’m using. 1/2 20. I will have a double banjo back and center carb, single on the front carb. Back banjo bolt is drilled to take a fuel pressure gauge, rubber hose will run from a filter/ pressure regulator on the firewall into the back carb, then on to the middle and terminate at the front. I got these from ‘stromberg97’, as that’s what these are made to fit, but I’m sure you can get them other places as well, just that this company happens to be in the UK. I went with these and not the stock style metal lines with tube nut because I’m squeezing my alternator in between the front carb and the valve cover, and needed the space.
 

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ozzie7

Well Known Member
Are you using the original 7/8" inlet fitting?
If so, keep in mind you are changing the sealing surface from the flare (green arrow) to a gasket (red arrow) in the pic below.
Might be OK if you can get the banjo fitting tight enough.
It looks like there is enough meat for the banjo fitting gasket to make a seal.
I would be checking those banjo fitting seals carefully and often for leaks.

Inlet flare to banjo fitting.jpeg
 

neilswheels

Well Known Member
You’re right Ozzie, it’s very tight in there, I will lightly modifying one or the other to make sure the washers seal. Thanks for pointing it out tho.
 
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