Fuel fittings always tighten at wrong angle?

[Terry Veiga]

Hello, I have tried way too many types of fuel fittings and combinations (brass, aluminum, chromed, adapters, elbows, etc.) and they all tighten down at random angles but never at the desired angle. How are you guys getting your fittings to be perpendicular?

Both these fittings on my fuel regulator tighten past the desired angle and doesn't align with the carb inlet nor the fuel hard line:

photo.JPG

[jzjames]

Thats a good question! How I do it is; when the fitting is at the point of being screwed in tight, I just stop at the angle I want and hope for the best.
If it’s not really tight at that angle then I’ll forget about being neat - and compensate elsewhere. (bend my tubing).

[Terry Veiga]

Thanks a lot jzjames, I also got a good tip on another forum for swivel elbows:

3/8 Male NPT to 3/8 Barb 90-degree Elbow Fuel Fitting
3/8 Male NPT to 5/16 Barb 90-degree Elbow Fuel Fitting

swivel-fuel-fitting.jpg

[Ranchero50]

Use a gas proof liquid sealant, position to the correct position as tight as you can and allow it to set up. Don't use tape as it can get in the carb and cause havoc.

[sparky72]

Depending on the fitting size, there is a range of number of turns past finger-tight that should result in a leak-free connection if you use a good gas-resistant liquid sealant on the threads. Somewhere in that range should put the fitting at the desired angle. See link below:

https://www.engineersedge.com/hardware/ ... _13424.htm

[Terry Veiga]

Ranchero50 and sparky72,

I'm very thankful you guys mentioned using a gasoline-compatible sealant because I had already finished up a couple other fittings using Rectorseal T Plus 2 Pipe Thread Sealant. I mean, I read the instructions and even thought as much, but a simple online search just confirmed it is NOT made for gasoline! Who said ignorance is bliss?? What brand sealant are you guys using?

The problem I'm having is that the fittings are simply not that snug at my desired angle. I have to go another ¼ turn before the threads snug well and if I settled less than that, I feel like I'd be relying on the sealant too much and will also miss out on the added benefit of the tapered threads doing any clamping and sealing.

I had also thought about using a banjo bolt fitting similar to the carburetor inlet, but those threads are shorter than I'd like and are untapered (if that even matters?). Plus, with a banjo already on the carb and adding two more on the regulator, I'd be leery of using too many nylon crush washers throughout my fuel line—they just seem flimsy and like an inevitable weak link. Does that make any sense?

Edelbrock-banjo.jpg

Here's an agricultural fitting I found that uses a lock nut and would be ideal (in theory), but I have not seen/heard anyone using these so I'm hesitant to be the first.

brass nozzle body fitting.jpg

I did find this ultra nice Earl's swivel fitting that is apparently made out of diamond encrusted Platinum at $57 plus shipping!

Earls elbow fitting.jpg

Hopefully the swivel-style fittings I attached in my other post will work out and I really like that they're less than $10 ea. Anyhow, hoping that you all won't see a "My truck went up in flames and burned down my house!" post from me anytime soon.

[Ranchero50]

Tighten it another turn or get the correct NPT tap and add as much thread as you need rotation (well a little less).

[sparky72]

Permatex 56521 would work well for this application. Try to leave the first thread or so free of sealant.

Like Ranchero50 said, another 3/4 turn or so to get the angle where you want it shouldn't hurt anything. You can go up to 3 or so full turns past finger tight with NPT fittings this size.

[jzjames]

You can go up to 3 or so full turns past finger tight with NPT fittings this size.

Why is that? Because tapered threads or brass pc.?

[sparky72]

You can go up to 3 or so full turns past finger tight with NPT fittings this size.

Why is that? Because tapered threads or brass pc.?

It’s because the male threads are designed to crush somewhat and interfere with the female threads as you torque the fitting down; this is what creates the seal.

I would get pretty nervous going beyond 2 turns past finger tight, but in theory you should be able to. My point is that just because it’s finger tight at the wrong angle doesn’t mean you are stuck with that angle. You should be able to bring it around another full turn past finger tight to get it tight, plus some fraction of a turn to get the fitting angled where you want it.

[jzjames]

makes sense.
Didnt realize it could be tightened up that much though.

[Terry Veiga]

Thanks Gents, I'll get some Permatex 59235 High Temperature Thread Sealant since it mentions high heat and fuel fittings in its specs. Plus, I'll swap out the existing chrome fittings and replace with the swivels I ordered.

I did want to mention though, I've stripped my fair share of threads over the years to know there's no way I can tighten more than half a turn past finger tight on this regulator. Maybe the '2-3 turns past finger tight' guideline is more for large galvanized piping or something, however, this regulator is pot metal (or aluminum?) and the tapered threads max out pretty quickly after finger tight—any tighter would be pushing it.

Click the image to see the bold tightening warning shown in the instructions:

dont-overtighten.png

At any rate, I appreciate everyone's input and you can bet I'll be checking and rechecking the lines once I finally get to start/drive this thing again, and I'm already figuring out how big of a fire extinguisher I can fit under the seat or possibly custom mount a large one underneath the bed.

Best regards!

[Ranchero50]

That's why you own a couple pipe taps and just cut the threads to where you need them.

[greyscar]

If you have Taps, you can cut Threads another 3/4 turn...........

[Terry Veiga]

Thanks Ranchero50 and greyscar, the swivel fittings seem to be working perfectly; I'll find out if they're truly leak-proof whenever I get the engine running again.

However, I do want to ask about your suggestion to cut additional threads. I thought the same thing early on, but both the regulator's ports as well as the fittings I had tried are all fully threaded. I'm assuming cutting threads wouldn’t have worked in this situation, correct?

fitting-fully-threaded.JPG