Looking to do the fuel rail mod to get rid of the hard lines on the front of the rail. My issue is I went to tap the front of the pass. rail the pressed fitting started to spin. I am going to have to build it up so I can tap it for an 3/8 NPT fitting. My question for people that have welded these rails, what filler material should I be using?

Mods: not sure if this is the right section as It has to deal with fab'ing and TPI. Move if necessary. Thanks.

 

Why don't you just remove the restricter plug and go 3/4 npt ?

 

3/4 NPT is way too big.
Here is what I did. I cut the fuel line off the front of the rail, made it flush and drilled it to tap for a 3/8 NPT fitting. As I started to tap it, the plug broke and started to spin within the bore of the rail. I am now left with a hole that I can tap for a 1/2 NPT, but the 1/2 NPT is too large and the threads will break through the top and bottom of the rail.
What I am going to do is ream the hole and place a piece of bar stock into it. Then I want to weld the stock to the rail to seal. Next I will drill and tap the stock for a 3/8 NPT fitting.
I want to know what kind of material the rail is made out of so I know what filler rod to use.

 

If you are going to be welding to the stock rails may as well just weld a -AN fitting of your choice direct to the rail

 

Your fuel rail is made from aluminum. It would be better if you tig welded the stock in as it is cleaner than mig.
Otherwise grind it or have a machine shop clean up the ends before you still and tap the lines.
Keeps everything nice and clean.

Cheers

 

What grade of aluminum filler? 4043, 5356? Yes it will be TIG welded. Depending on what grade of aluminum the rail is made out of (6 series or 4 series) will bias my decision on filler.

 

Remove the restricter, it is a press in fit with a o-ring seal. I apply heat with a torch. Sorry you are correct it is 1/2 npt.

 

I measured and it looked like the 1/2 NPT tap is larger than the rail at its thinest points. So it wont work for me.

 

So no one knows what filler rod to use when welding the fuel rail?