Sanity check on fuel filter fittings

[Bill Elliott]

I posted this in my build thread, need to getting thumbs up from people.

I installed Aeromotive 3/8 npt to AN-6 fitting into filter with permatex high temp thread sealant. The fitting only went about 3 or 4 threads in and that was it . Just wanna make sure this all looks/is normal and good to go.

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[CraigS]

I would be a little nervous about the minimal thread engagement. But I would hopefully fix my nervousness but being super careful about building the AN hose and tying it down 3-5" away w/ an Adel clamp.
https://www.aircraftspruce.com/catalog/pnpages/MS21919-DG35.php?msclkid=80d49746f63618fa13a6f3a4784b031a&utm_source=bing&utm_medium=cpc&utm_campaign=TNT%20-%20Shopping%20-%20NB%20-%20Desktop&utm_term=4580977758708817&utm_content=All%20Products
You know how AN hose always has a built-in curve to it? Try your best to use that curve to your advantage. Also use an AN hose end that will swivel once installed on the hose. IE, when you tighten the hose end on to the adapter, the hose should still be able to swivel. This helps to relieve any stress applied to your adapter.

[Bill Elliott]

I would be a little nervous about the minimal thread engagement. But I would hopefully fix my nervousness but being super careful about building the AN hose and tying it down 3-5" away w/ an Adel clamp.
https://www.aircraftspruce.com/catalog/pnpages/MS21919-DG35.php?msclkid=80d49746f63618fa13a6f3a4784b031a&utm_source=bing&utm_medium=cpc&utm_campaign=TNT%20-%20Shopping%20-%20NB%20-%20Desktop&utm_term=4580977758708817&utm_content=All%20Products
You know how AN hose always has a built-in curve to it? Try your best to use that curve to your advantage. Also use an AN hose end that will swivel once installed on the hose. IE, when you tighten the hose end on to the adapter, the hose should still be able to swivel. This helps to relieve any stress applied to your adapter.

So this doesn't make me feel comfortable at all, maybe I should submit to Aeromotive?

[rich grsc]

Those fittings do not look like NPT. The fitting installed in the filter is different then the one in the picture

[Railroad]

For what it is worth, the description in the posted part pic, states NPT. Cannot tell about the filter pic.
You might remove the fitting and look inside the filter housing, making sure there is not an inverted flare flange.

[Bill Elliott]

I'll look in the filter housing to see if it is inverted flare. But the parts I received are as stated on the Aeromotive site. Fitting is part number 15615 and the filter is 12317. Ill take the fitting out and get a better picture of just the fitting.

[Bill Elliott]

For what it is worth, the description in the posted part pic, states NPT. Cannot tell about the filter pic.
You might remove the fitting and look inside the filter housing, making sure there is not an inverted flare flange.

So this is what I have, I have also emailed Aero with pictures to find out what they say. But I value your guy's input.

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Also, if we find out everything is as it should be, can I still reapply thread sealant and reinstall

[Railroad]

You are getting enough thread engagement. I would put some thread sealant on the filter side, also, but not so much it goes inside the housing.
Make sure your filter location is clear your tire/wheels and easy to access. It looks to be on the outside of the frame, which should be OK.

[CraigS]

Wow the expected taper on those 'NPT' threads sure isn't obvious is it? Can you go to the hardware store and grap any fitting that is 3/8NPT to use as a test?

[rich grsc]

Craig has a good idea. The fitting you have could be NPT, just machined differently than the description photo, hard to be sure from the picture.

[edwardb]

Quick Google search shows a 3/8" NPT should go in anywhere from 3-6 turns (depending on who you believe...) without resistance, and then another two turns to tighten and seal. Yours looks light to me. Aeromotive clearly shows that filter and those fittings as 3/8" NPT. Not a bad idea to check with another 3/8" NPT fitting. Super common at your local hardware store if you don't have any. Would be good to hear back from Aeromotive before deciding. Worst case is chase the filter threads with a 3/8" NPT tap. I've done that before on other applications and it's easy to cut the threads for a few turns to allow more turns before tightening. But maybe you don't want to disturb the Aeromotive filter. Which I understand.

[Bill Elliott]

I talked to Travis(Fman) and he said he had the same issue but no problems with it. For now I will wait for response from Aeromotive . I find it hard to believe that those threads are cut wrong on the filter. Wouldn’t they be cutting those in mass quantity with the same jig , cutter or whatever they thread those with? Don’t know why they would design something that would make everyone question if the product is correct item, and make it look like there is an install problem.

[Bill Elliott]

Got my response from Aeromotive

"You should be fine. The NPT is a tapered thread, so it will get tighter the more you engage the thread and deform the thread, Which is how NPT thread seals in addition to the thread sealant."

So gonna let it ride.

[BrewCityCobra]

For reference, I have the same fuel filter and my joint looks like the following:

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Only difference is I used Loctite 545 as my sealant instead of permatex.

[Bill Elliott]

For reference, I have the same fuel filter and my joint looks like the following:

189192

Only difference is I used Loctite 545 as my sealant instead of permatex.

Wow, looks like yours is fully seated. But since Aeromotive themselves didn't see an issue with mine, and Travis had same type of result , I will leave it as is and watch it closely during first start.(can't wait for that)