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Rain cap for fuel

Badmoonraising

By Badmoonraising
in General Mooney Talk

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Badmoonraising Enthusiast

Badmoonraising

Posted
Posted

Just wanted to share this with others whom must park their Mooney's outside. The previous owner warned me that water can migrate into fuel tanks so I made this magnetic rain cap. To be honest I copied the idea from an AME on the same field as me. In his case he used a tupperware lid. I couldn't find the same lid so I made my own. 

I vacuum formed thin polypro over a ceramic magnet purchased at Home Depot. Then I stacked the remaining magnets on the vacuumed magnet. The seal is glued to the plastic. It seems to hold well. I plan to wrap some black tape around the exposed magnets so they are not knocked off when I throw the rain cap in the back of the plane. 

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  • Like 3
jlunseth Grand Master

jlunseth

Posted
Posted

That's a great idea.  I once sumped about a pint and a half of water/gunk out of a rental Mooney that had suffered that exact failure.  Goo lesson in why we always sump.

RobertGary1 Grand Master

RobertGary1

Posted
Posted

 I've been outside for two decades. I change the two seals at annual and never found a drop of water in the tanks. Some drops will slip by when you remove the cap but the fuel suspends a certain amount of water anyway (otherwise you'd always have water from internal condensation)  

-Robert

Mooneymite Grand Master

Mooneymite

Posted
Posted
11 minutes ago, LANCECASPER said:

On Beechtalk there's a guy that sells the high quality blue Fluorosilicone orings at a good price. Well worth it!

https://www.beechtalk.com/forums/viewtopic.php?f=44&t=130666

Are these the right ones?

https://www.amazon.com/gp/product/B0055E1RLM?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01

Andy95W Grand Master

Andy95W

Posted
Posted
44 minutes ago, LANCECASPER said:

On Beechtalk there's a guy that sells the high quality blue Fluorosilicone orings at a good price. Well worth it!

https://www.beechtalk.com/forums/viewtopic.php?f=44&t=130666

I'm still a little skeptical about the ability of the material to handle the specific compounds present in 100LL fuel.  

Also, for that price, I think I'll just keep replacing the o-rings regularly with the standard MilSpec fuel resistant parts.

LANCECASPER Grand Master

LANCECASPER

Posted
Posted
12 minutes ago, Andy95W said:

I'm still a little skeptical about the ability of the material to handle the specific compounds present in 100LL fuel.  

Also, for that price, I think I'll just keep replacing the o-rings regularly with the standard MilSpec fuel resistant parts.

Quite the opposite - the fluorosilicone handles fuel much better than the standard o-rings.

http://www.csobeech.com/fuel-caps.html

LANCECASPER Grand Master

LANCECASPER

Posted
Posted
49 minutes ago, Mooneymite said:

Are these the right ones?

https://www.amazon.com/gp/product/B0055E1RLM?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01

They are the ring one for the outside ring but they are also more expensive than getting the kit from the guy on Beechtalk. His kit includes both o-rings and the cotter pin. Make sure you replace the small o-ring inside since water sits in the recess of the center of the cap and can get past a bad o-ring easily.

http://www.csobeech.com/fuel-caps.html

  • Like 1
Marauder Grand Master

Marauder

Posted
Posted
They are the ring one for the outside ring but they are also more expensive than getting the kit from the guy on Beechtalk. His kit includes both o-rings and the cotter pin. Make sure you replace the small o-ring inside since water sits in the recess of the center of the cap and can get past a bad o-ring easily.
http://www.csobeech.com/fuel-caps.html


I think I asked before. Are these for the non-bladder caps?


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Marauder Grand Master

Marauder

Posted
Posted
How many years does it need to last though? Changing annually I've not had fuel get into the tank in 20 years of being outside just using the standard rings.
-Robert


You must be getting great fuel economy if you never needed to add fuel in 20 years.

The gaskets on my bladders are fluorosilicon and have been on the plane for a long time. They don't leak and my mechanic told me that they are still fine. Then again, they were $50 each for the big ones and I am sure he made sure they were fine.


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  • Like 1
Bob_Belville Grand Master

Bob_Belville

Posted
Posted
6 hours ago, Marauder said:

 


You must be getting great fuel economy if you never needed to add fuel in 20 years. emoji3.png

The gaskets on my bladders are fluorosilicon and have been on the plane for a long time. They don't leak and my mechanic told me that they are still fine. Then again, they were $50 each for the big ones and I am sure he made sure they were fine.


Sent from my iPad using Tapatalk Pro

 

Do they get lubed at annual? DC4?

 

1964-M20E Grand Master

1964-M20E

Posted
Posted
10 hours ago, Marauder said:

 


I think I asked before. Are these for the non-bladder caps?


Sent from my iPad using Tapatalk Pro

I beleive they are the ones for the non bladder tanks.  Those of us with bladders have an odd o-ring.

  • Like 1
M20F-1968 Veteran

M20F-1968

Posted
Posted

After reading this thread, I still am not convinced I have good data leading me to replace the MIL spec O-rings.

1) I believe that the fluorosilicone O-rings last longer than the factory originals, but I do not know how much longer than the 1 year recommended change interval is to be expected. 

Has Mooney chimed in on this making a recommendation?

2) If they could be obtained a 2X the cost, rather than 5-10X the cost, perhaps it would make sense to use them and change annually, thinking that they will be a better product.

3) I have not yet seen any data on what the true replacement part number and dimensions of the new part.  It may not be just measuring them as the density/compressibility of the Fluorosilicone must also be considered.

4) Can someone who has used them post the dimensions, part number and source of the Fluorosilicone parts and I'll give them a try?

John Breda

mooniac15u Veteran

mooniac15u

Posted
Posted
1 minute ago, M20F-1968 said:

After reading this thread, I still am not convinced I have good data leading me to replace the MIL spec O-rings.

1) I believe that the fluorosilicone O-rings last longer than the factory originals, but I do not know how much longer than the 1 year recommended change interval is to be expected. 

Has Mooney chimed in on this making a recommendation?

2) If they could be obtained a 2X the cost, rather than 5-10X the cost, perhaps it would make sense to use them and change annually, thinking that they will be a better product.

3) I have not yet seen any data on what the true replacement part number and dimensions of the new part.  It may not be just measuring them as the density/compressibility of the Fluorosilicone must also be considered.

4) Can someone who has used them post the dimensions, part number and source of the Fluorosilicone parts and I'll give them a try?

John Breda

Mooney specifies MS29513-010 and MS29513-338 per Service Bulletin 229A http://www.mooney.com/en/sb/M20-229A.pdf

AD 85-24-03 requires compliance with Mooney SB 229A.  I don't see how the fluorosilicone o-rings are a legal replacement.

  • Like 1
LANCECASPER Grand Master

LANCECASPER

Posted
Posted
9 hours ago, M20F-1968 said:

After reading this thread, I still am not convinced I have good data leading me to replace the MIL spec O-rings.

1) I believe that the fluorosilicone O-rings last longer than the factory originals, but I do not know how much longer than the 1 year recommended change interval is to be expected. 

Has Mooney chimed in on this making a recommendation?

2) If they could be obtained a 2X the cost, rather than 5-10X the cost, perhaps it would make sense to use them and change annually, thinking that they will be a better product.

3) I have not yet seen any data on what the true replacement part number and dimensions of the new part.  It may not be just measuring them as the density/compressibility of the Fluorosilicone must also be considered.

4) Can someone who has used them post the dimensions, part number and source of the Fluorosilicone parts and I'll give them a try?

John Breda

https://www.beechtalk.com/forums/viewtopic.php?f=44&t=130666

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