Fuel line fittings

jlfernan · Post by **jlfernan** » Wed Aug 16, 2006 11:32 pm

What are or where can I find the torque values for the fuel line fittings?

Post by **Spike** » Thu Aug 17, 2006 8:41 am

Did you try AC43.13?

captain_john · Post by **captain_john** » Thu Aug 17, 2006 6:03 pm

Not fer nuttin but, they say Mmmmmpfh tight is right.

I haven't gotten to that stage yet, but that is what I hear.

WS, have you researched this yet?

CJ

JohnR · Post by **JohnR** » Thu Aug 17, 2006 9:17 pm

to Rivetbangers Jorge!

Great question, I've heard everything from tighten it one flat after contact to REAL tight. Not very scientific. Hope someone has a good asnswer for you on this.

I'll be watching

jim_geo · Post by **jim_geo** » Fri Aug 18, 2006 12:40 am

Seems to me it's not actually a torque value. Since I'm in the early stage of running fuel lines myself I'm thinking I'd better find out also. I'll let you know in a day or two when I get a round toit.

Wicked Stick · Post by **Wicked Stick** » Sat Aug 19, 2006 2:31 pm

CJ,

I've not researched it yet.. But most probably will just tighten them using my well calibrated arm/wrist/hand method.

jim_geo · Post by **jim_geo** » Sat Aug 19, 2006 2:35 pm

Well as with most projects there is an area covered that's closer to an art than science and it looks like fuel line fittings is it on this one. I went over to the airport and talked with my favorite A&P yesterday and he copied a sheet with lots of info about fittings Aluminum and Steel for us. Once my camera and I share the same space I'll get a jpeg of it and post a link to the picture of the sheet for all to download. For right now I will put the info for 3/8" fitting Aluminum (probably the one needed). Torque limits in INCH POUNDS Min.-110 Max.-130. Pretty light torque. When I asked him about this this he said you do a lot of fuel lines and you just get a feel for it. Indicating to me there's an art to it.

Cherokee Driver · Post by **Cherokee Driver** » Sat Aug 19, 2006 4:16 pm

Hope this helps

CD

captain_john · Post by **captain_john** » Sun Aug 20, 2006 10:05 am

Cool, CD!

You musta scanned it from 43.13 yourself?

Tell me, do you plan on doing the calculations for the crowsfoot wrench and all that stuff?

I am thinking that once a "feel" for torque is found, that may be enough?

Whacha gonna do?

CJ

Cherokee Driver · Post by **Cherokee Driver** » Sun Aug 20, 2006 3:14 pm

Actually, I am sort of a reference hound. I have been collecting books and reference stuff for a couple of years. My mechanic instilled in me a curiosity in doing things by the book so I picked up a lot of books, and I refer to them often. When I see a post that is looking for something I may have on file, I feel a need to do the research and share it. As for the Crows foot calculations

I'll let you guys do the math.

CD

Dan A · Post by **Dan A** » Sun Aug 20, 2006 6:07 pm

The clcosest "feel" is one flat past snug.
Dan A

jim_geo · Post by **jim_geo** » Mon Aug 21, 2006 1:40 am

That's a nice bunch of numbers to crunch. It doesn't have to be that cumbersome though. The picture below is the actual combo I used to tighten the nuts at the bottom of the spar carry through.

So the way you arrive at the ratio is this. D1 plus D2 divided by D1 gives you your ratio. Pick a number on your torque scale and multiply it by your ratio. If it falls into the torque range you like use it. If not keep looking for a number that does. For instance with the set up shown it took a setting of 33 inch pounds to give me just a smidge less than a 70 inch pound torque. Or divide the desired torque by the ratio and the result is is the torque to set the wrench to.

jlfernan · Post by **jlfernan** » Mon Aug 21, 2006 5:59 am

Thanks for all the help guys. When it comes to calculating torque with an extension, go to our friend Checkoway's site and use this handy dandy calculator: http://www.rvproject.com/mechanic.html. Higher math gives me a headache.