Jump to content

Fuel and Oil Hoses


Recommended Posts

I have started to question anything done on my airplane and since I can't get to my mechanic on a day to day basis - I turn to the mooneyspacers for info.

Today's questions: 

1965 M20C Oil Cooler.  The fittings are facing inboard...is this correct or should they be on the outboard side?

2nd question: The aircraft has a fuel flow transducer installed between the fuel pump and the carb.  The fuel line has  has a 360 degree loop when it looks like the hose could have run directly from the transducer to the carb.  Is it more proper to have the big loop or should I have a hose made that runs directly from the FF transducer?

Lastly - is that an indication of an exhaust leak at the muffler? - (its a minor leak at the junction of the adjacent fitting)

 

Bottom line - None of the hoses have manufacture dates, test dates or other info on them or any data plates so they are going to be replaced before annual because they could be from 1965...or who knows when.

IMG_3589.JPG

FullSizeRender.jpg

Edited by Drumstick
Link to comment
Share on other sites

This is how mine are too. I remember when I replaced my lines (and cooler, don't ask) that I took extra care to get them angled as low as possible to prevent creating an unauthorized smoke system, as cool as that'd be.

When ordering cables take pictures of fittings when you send your order in. They used the wrong fittings on mine so I could use one of the two $200+ hoses and once made they said they cannot change the fitting.

Link to comment
Share on other sites

The loop in the fuel line is probably correct, the fuel transducer is mounted on the firewall and the carb is obviously mounted to the engine, the loop will allow for vibration differences to be dissipated between the two ends.  

 

Ron

Link to comment
Share on other sites

1 hour ago, N6758N said:

That is just rust you are seeing on the muffler, not an indication of an exhaust leak. 

There was a little yellow stain adjacent to the fitting on the opposite pipe.  It wiped off - no biggee...  I'll have A&P look at that fitting at annual.

 

1 hour ago, Marcopolo said:

The loop in the fuel line is probably correct, the fuel transducer is mounted on the firewall and the carb is obviously mounted to the engine, the loop will allow for vibration differences to be dissipated between the two ends.  

 

Ron

Makes sense to me!  Thanks!

Link to comment
Share on other sites

Ugh, regarding the FF transducer with the 90° elbow on The IN end...

You may want to find the instructions for installation for that device.  They can be sensitive to eddy currents caused by sharp turns...  there is probably a minimum distance of straight line required both on IN and OUT...  it may be defined by a 10:1 X ID of the fuel line. They may even tell you a 45° elbow is better that close in...

The sensor is kind of like a Mooney wing.  It likes laminar flow for accuracy.  90° elbows are anti-laminar flow...

Do you see any strange FF numbers at full throttle, or while close to idle?  Any challenges of getting the K factor to work out?  How accurate is your fuel totalizer?

Overall it is a simple device and hard to goof up.  Looks like there is opportunity for improvement.  The install manual will define how to improve it...

PP thoughts only, but have some industrial sensor experience...

Best regards,

-a-

Note: yellow stains on plumbing fittings are often put there intentionally.  They are a sign that the fitting has come loose.  Your mechanic can put them back.  They are similar to something called a torque seal...

Edited by carusoam
Link to comment
Share on other sites

49 minutes ago, carusoam said:

Ugh, regarding the FF transducer with the 90° elbow on The IN end...

You may want to find the instructions for installation for that device.  They can be sensitive to eddy currents caused by sharp turns...  there is probably a minimum distance of straight line required both on IN and OUT...  it may be defined by a 10:1 X ID of the fuel line. They may even tell you a 45° elbow is better that close in...

The sensor is kind of like a Mooney wing.  It likes laminar flow for accuracy.  90° elbows are anti-laminar flow...

Do you see any strange FF numbers at full throttle, or while close to idle?  Any challenges of getting the K factor to work out?  How accurate is your fuel totalizer?

 

Fuel Flows are stable and seem spot on.  If the Shadin says I have burned 16.x gallons I usually see 16.x gallons on the 100LL pump.  I think I will leave it alone other than to replace the hoses.  If its funny after the hoses go on...this will be the first place I start to look.  FF transducer was installed 10 years ago by previous owner.

 

However - this brings up and interesting question.  The Insight G2 has a FF indication and the Shadin also shows FF.  The FFs sometime do not exactly match.  I wonder if there is ANOTHER transducer in this airplane somewhere...might it be on the other side of the firewall?

Edited by Drumstick
  • Like 1
Link to comment
Share on other sites

All that fire sleeve is doing is keeping you from inspecting the hose because it is ripped open and held on with zip ties.. I'm not sure how much direct flame zip ties can withstand but I'm sure it's not the 15 minute standard

  • Like 1
Link to comment
Share on other sites

1 minute ago, jetdriven said:

All that fire sleeve is doing is keeping you from inspecting the hose because it is ripped open and held on with zip ties.. I'm not sure how much direct flame zip ties can withstand but I'm sure it's not the 15 minute standard

Hoses and fire sleeve are being replaced with 124J "brown" Teflon....I had the same question about the firesleeve though...

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.