Hello Fred,
You might want to have a look at the tightening specifications from the manu
facturer of those fittings. It is interesting that they advise against torqu
e and use number of flats instead. See pages 21 and 22 of https://www.parker
.com/literature/Tube%20Fittings%20Division/Assembly_Installation.pdf
Be safe
A266
Michael Grass
Sent from my iPad
> On Mar 15, 2019, at 3:10 PM, Fred Klein <freddythek10@gmail.com> wrote:
>
> I=99m reminded of the value of this list after contacting Ron Pagori
s who had not posted for a long timeand I want to thank him for bri
nging to my attention the subject of the use of aluminum fuel line fittings i
n the engine compartment.
>
> Further research on the subject generated this response from Bud which he w
illingly shares with our list:
>
>> Fred,
>> I do not have problems with aluminum AN fittings. I do have problems wit
h FWF techniques:
>>
>> AN fittings or even steel flare fittings need some sort of fastening to p
revent loosening, which is common. I see some of the fittings you use have a
safety wire hole. Use it. They do loosen, especially on fuel injection li
nes. Hence the automotive and marine industry is going to special fittings.
Oil fittings get safety wiring also.
>>
>> I also have problems with any hard line going to an engine, from a firewa
ll. That is a broken fitting waiting to happen. The engine to fuselage fit
ting should always be a flexible line of course. If the line is steel brade
d or firm rubber, its flare fitting will tend to loosen with age without som
e sort of fastener fixing them such as safety wire or crimp anti spin connec
tor. Reason, over time the shake of the engine and the firm rubber or brade
d line will shake until the flare fitting begins to loosen. We had this pro
blem on jet engines. Safety wire flare fittings in some way. If the flare f
itting has no safety wire hole, I use a Breeze clamp bent to fit on a fittin
g (like on the oil tank fittings on the Rotax) rather than drilling the nut e
dge. Once I have the Breeze clamp fitted, I safety wire the Breeze clamp sc
rew so it won=99t loosen, then safety wire the clamp to a fixed point t
o assure the fitting stays tight.
>>
>> That said, I tend to use push on or barb fittings screwed into an NPT fit
ting for oil and fuel with specified clamps so the fitting won=99t loo
sen. However, Aluminum NPT fittings can crack if not supported properly, ma
ybe that is why your inspector prefers brass, which bends, or steel which is
much stronger. He may have been concerned about the 90 degree fitting comi
ng off the fuel line manifold for bending. I can=99t say. What I can
see in the photo looks like a safe fitting if it is suitable for the fuel o
r oil temp and pressure requirements of the engine manufactuer.
>>
>> Best Regards,
>> Bud Yerly
>
>
> <DSCN8253.jpeg>
>
> While I will continue with my aluminum fittings, I will most certainly ens
ure that they are properly safety-wired! Thanks Ron & Bud!
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