Compression Fitting on 3/8 Nicopp Hardline Question

[nuhale]

I tried to get a solid answer in searching the forum but could not find a definitive answer regarding compression fittings with nicopp hard fuel line. I currently have a gen2 coyote setup using the GM filter/regulator so operating 58psi (see it fluctuate up to 80 when running). I ran a 3/8 nicopp hard line up the 4" PS frame rail up into the bay where I used a aluminum Fragola flair fitting to 6AN. The inverted tube nut is stainless to the aluminum fragola fitting. I can't get the flair to re-seat after I recently changed the line to fuel rail and has a trace fuel leak. It's in a very tight space and will have to remove the nicopp line to re-flare which I really don't want to do. My quick fix was hitting the threads and underside of the flare with blue monster PTFE paste which is holding fine. Cutting and using a compression fitting would be ideal.

Q: Will an aluminum compression fitting like this one in link work with 3/8 nicopp line? Anyone use something similar with result on a 50-70psi EFI setup?

Thanks in advance.

https://www.amazon.com/dp/B09VL2CWDY?ref=ppx_yo2ov_dt_b_product_details&th=1

[Pmieras]

I took a look at the fitting your thinking of using. I would assume that it should work since it seems to be rated for up to 1000psi and your fuel system should be putting out around 58psi. I've never used that type of fitting before. I would possibly try it since if it doesn't work you may end up pulling off the line anyways. I know a lot of the flare fitting are sensitive to proper torque, cleanliness during make up and tightening, condition of the flare / seat, etc. Might be worth checking those things too.

The only type of "compression" style fitting I've used in the past with great success is Swagelok. I used Swagelok fittings when I installed a line lock on a brake system which see's much higher line pressures than the fuel system. They could be a little pricey.

For the fluctuation in the fuel pressure I would also assume that could be regulator problem, fuel rail size, if it's a problem at all.

[nuhale]

I took a look at the fitting your thinking of using. I would assume that it should work since it seems to be rated for up to 1000psi and your fuel system should be putting out around 58psi. I've never used that type of fitting before. I would possibly try it since if it doesn't work you may end up pulling off the line anyways. I know a lot of the flare fitting are sensitive to proper torque, cleanliness during make up and tightening, condition of the flare / seat, etc. Might be worth checking those things too.

The only type of "compression" style fitting I've used in the past with great success is Swagelok. I used Swagelok fittings when I installed a line lock on a brake system which see's much higher line pressures than the fuel system. They could be a little pricey.

For the fluctuation in the fuel pressure I would also assume that could be regulator problem, fuel rail size, if it's a problem at all.

Yea, I see the pressure rating for the part but where my concern is the interaction between nicopp and the fitting. Many of the literature or information I can find details use with stainless/steel lines.

[Papa]

Compression fittings work fine with NiCop tubing. I'm using these fittings from Breeze:

https://breezeautomotive.com/shop/fitting-3-8-od-tube-to-06an-male-316-stainless-steel/

They are a little more expensive, but came highly recommend

[Hoooper]

I used tube nuts on my nicopp lines. For testing I ran the pressure to 100 PSI and did not have any leaks. My pressure is static 60 PSI and no leaking at 3k miles so far

[mikeinatlanta]

Do you have any pics of the leaking fitting, specifically the flare on the tube? Cheap flare tools or issues during installation can put a scratch across the sealing surface. This surface can be burnished and repaired if the damage isn't too bad.

[JohnK]

+1 on using the Let-Lok compression fittings from Breeze. I use them on all of my 3/8” hard line to braided flex transitions and they work flawlessly.