Roger Lee

Why we should replace engine isolators

37 posts in this topic

I'll check a fitting or two with a microscope when I get a chance to find out what you are talking about, but I suspect the "barbs" you are referring to are actually the machining burrs that aren't being cleaned off (they should!).

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Dick, I'm just finishing up a hose change on a CTSW. I will try and measure exact lengths when I'm finished. I do use the 1/4" Gates hose, but I'm not really a fan of the Barricade hose. For the other hose I've been using this, https://www.amazon.com/BMW-Genuine-Fuel-Hose-13/dp/B00DD9JH4K  I bought the first of this from Wurth USA, but they switched suppliers and the new hose is not worth using. I called these people and ordered, but you should be able to get it from any BMW dealer. It is the proper DIN spec hose, and fits nicely, though some fittings are still a tight fit.

 

Oil hose is 12mm. Lockwood used to sell some 1/2" hose, but now sells something that looks like the Rotax oil hose.

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Rotax does not sell oil hose. Oil hose comes from the service centers or the aircraft MFG and they get to choose. Lockwood was using Aeroquip at one time. I don't buy from them so I don't keep up on their changes.

 

ED,

 

If you damage the inside liner of the rubber fuel hose with a clamp you have over tightened it. It takes very little clamp pressure on a barbed fitting under our pressures to hold the hose in place and keep it from leaking. Using fuel injected hose is not a good choice because it has no give.

 

I don't condone this force, but think of your comment on forcing the hose over the barb. That means the hose itself is applying more than enough force to probably hold it in place and yes you could damage the hose. I was there once with my first two hose changes because that's what FD had on the planes.. I immediately saw this was an extremely poor practice.

 

I'm with Corey. The rubber hose should not need to be forced over a barbed fitting. It should slide on without force and the proper clamp tension which would only be a little be applied. I do not need to force any oil, fuel or coolant hoses on. Some do slide easier than others, but none are applied with force that may damage the liner.

 

I mean do disrespect here, but I sense you may be a little jaded on some of your engine issues and these may have come from your maint. people not keeping up on what is called "BEST" maint. practices. These change with time and all people including so called experts need to keep up and change with them.  Each LSA aircraft can be different. We all have had a learning curve here since 2006 and the first forum. Things have changed, ideas have changed, manit. procedures have changed and if someone who works on these aircraft fail to read, research and learn the changes the history of less than acceptable maint. practices persist.

 

 

WE ARE ALL TEACHERS AND WE ARE ALL STUDENTS!

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Tom, I appreciate your help.  My comments about "bleeding fingers" pertained to the super stiff fuel injector hose that we were told to use 5 or 6 years ago.  This was absolutely the wrong hose due to it's stiffness and inablility to expand over the fittings. During my time as a fuel tank and fuel hose designer, the auto industry never allowed the assembly plants to use soap in any manner for lubrication for installing fuel hoses.  Thwe soap remains and can allow fuel hoses to slip off of fittings during crashes.  A "murple" solution of alcohol and water was used.  This provided lubricity only during the fitting of hoses and would evaporate soon afterwards.

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Laugh if you must, but I find a tiny bit of Pledge squirted in the hose end helps lubricate it going on, to no ill effect that I can discern.

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Roger,

 

I get it that you make barbed fittings work but what does work mean?  It means it doesn't leak.  Gates is clear on the fact that rubber fuel line and barbed fittings are not compatible.  If you look at the barbs under a low power lens you we see man sharp barbs (hooks) that can only penetrate into the inner lining and allow fuel to access the other linings.  If you don't cause punctures your other choice is leaks.

 

Best practice is to use compatible hose and fittings even if no one does it.

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I guess whatever works for our hoses and will defer to those of you with experience working on aircraft - a little soap, slobber or pledge, etc.  The only thing I seem to hear is to not use silicone based lubricants on the fuel system.  Eddie had his horror story about the silicone sealer.  I really hate the barbed fittings.  Nipples with annular beads would be best on the fuel system. such as is done with the coolant and oil tubes on our CT's.

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"Gates is clear on the fact that rubber fuel line and barbed fittings are not compatible."

 

The average use installation and big liability. They say don't and they are covered if you do.

 

 

​No doubt the smooth bore flared end fittings would be better, but unfortunately we weren't ask during any engines development or MFG.

 

So you're right. We make it work and it has been working like this since the early Ultralight days.

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I guess whatever works for our hoses and will defer to those of you with experience working on aircraft - a little soap, slobber or pledge, etc. The only thing I seem to hear is to not use silicone based lubricants on the fuel system. Eddie had his horror story about the silicone sealer. I really hate the barbed fittings. Nipples with annular beads would be best on the fuel system. such as is done with the coolant and oil tubes on our CT's.

The idea is not to use any kind of lubricant or sealant that can't break up on it's own. Since that doesn't actually exist, we do the next best thing: use the lightest oil that we can to do the job.

 

Anyways, if people don't like the idea of mild soap and water, you can use a drop of engine oil where there is no coolant or hydraulic fluid. Coolant and hydraulics lubricate too, so you can put those on their own lines.

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Can i confirm this please.;   CTSW 2006   Each of the 4 engine mounts has 4 rubber isolators ?   2 front and 2 back.?    So, 4 rubber isolators per mount ... 4 mounts = 16    On each mount we can only see 1 of the outer rubber isolators as the inner rubber isolator is inside the metal tube?     Am about to change the rubber isolators and wanted to confirm this please - Thanks

Rubber Isolator

Rubber isolator needing a change

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