Over the past few months having trouble with my fuel system leaking. The threads are weak at the end of my secondary fuel rail causing the gas to leak out. Is it possible to use a tap to clean them up a bit with it being npt. How should I fix this? Whats the best product i can buy that will sill threads? If this thread needs to be move do so. I always had better response in the section of the forum so i decided to post here.

 

If it's NPT, a tap should be easy to find. You might have good luck with hylomar as a thread sealant. There are many here who've used hylomar in one way or another, or at least have heard of it.

 

Also, teflon tape is impervious to fuel. I use it on my fuel system.

 

Teflon's a pain in the ***. Loctite thread locker works great.

 

I only had luck with teflon once. All the other times it would hold for a few days and then slowly start leaking.
But can the threads be fixed with a tap?

 

The threads are tapered so if the fitting's not allready down to it's last thread when its tightened down you can run the tap further down and yes, it will help to cut new threads. Just don't go too far or you won't be able to tighten down your fitting. Oh, and make sure the thread-end of your fitting isn't blocking the injector feed hole in the rail.

 

I am not visualising weak threads

why does a japanese fuel line have american pipe threads ?

using a pipe tap will MOVE the taper further down the pipe, does this pipe have the ability to move to accomodate the shortening of the pipe ?

how are the threads in what the pipe threads into ?

it sounds like you might have a vibration problem, are the componants secured or are they able to move ?

 

because NPT is a common standard for tapered threads the world over

 

Use a crush washer.

-billy

 

Do you even know what a pipe thread is??

I work with threads all day long 5 days a week. Remove the fitting, run a tap in there to clean the crap out that may be in there then get your hands on some loctite 545. You don't need to put much on there, make a bead that fills one thread all the way around. Don't need to tighten it a lot either, just snug. This has worked for me on god knows how many parts.

 

ok, what i mean when I say the threads are weak is, some of the threads have been pulled out. I can screw the ntp adapter all the way down by hand. I dont think I can fix this. I have spent more time and money trying to fix it than what the damn thing is worth. Some threads are pulled out the center, some at the end. Even if I cut some of the rail off I dont think it will mater. It uses a 3/8 inch pipe thread, i dont think a 1/2 will work due to the size of it. Its a rail for 1600's. Does anybody know what a fuel rial is made of ? By the looks of it, it looks cheap. Damn not worth $200.
If i dont think of something reasonable by tonight, Im ordering one tommorow. I just hate to see ll the time and success.

 

I use 2 kinds of threads sealants, on threads in good conditiom, I use Masters metallic, on threads that are worn I use a product called "expando" which mixes up with water, to form an expanding cement like seal, I have never had an "expando" joint leak, even on ammonia systems at 200 psi. One of the problems with NPT and why the factory stuff is typically a flat thread with a crush washer, is that when tightened, the npt taper will crack a fuel rail made out of aluminium, so you can't go to town tightening it, and being alumiminim, it grows with heat quite a bit, so when the fuel rail gets warm it the fitting loosens off, hence the need for a crush washer and flat thread sealing rather than the taper, but if you warm the fuel rail up, when you screw in the NPT, you will have better results..Max

 

One thing I like about the loctite 545 is it expands when there is a lack of oxygen. Sooo when you turn in the fitting by hand and give it a little snug the air will be gone then it expands taking up space that the threads dont fill.