Pros and cons with teflon fuel-lines?

[ao.frog]

Hi you engine guru's out there.

I bought the IO-360 Lyc from Vans about two years ago and a couple of days ago, it was time to install the FT-60 FF sensor (the"red cube").
As on my other -7, the plan was to install the sensor on the fuel-line beetween the engine driven fuelpump and the fuel injection servo.

However, the airplane-shop who installed the same type of sensor on my first -7 couldn't do it this time since the fuel-line Vans provided in their FF-kit now is made of teflon.
The fuel-lines on my first -7 where made of the usual rubber-type and they had no problem working with them back in 2007.

I now have a couple of options.

1) Send the fuel-line and the sensor to someone in the US who can work with teflon fuel-hoses.

2) Have the airplane-shop make new fuel-hoses made of rubber and have them install the FF-sensor on that one.

Since option 1 is both time-consuming and expensive, I would rather go for option 2, but then I'd have rubber fuel-lines.

I don't mind having rubber fuel-lines at all, but is the any good reason I should keep the teflon-lines?
Any advantages beside that those will live "forever"?
I don't mind changing the rubber-fuel lines every 10 years...
(I have read somewhere that rubber-lines schould be replaced at that interval)

So: before making any decitions, it'd be interesting to hear what you engine-guru's are saying about teflon vs rubber?
(Mel; are you there?? )

[Mel]

Originally Posted by ao.frog

I don't mind having rubber fuel-lines at all, but is the any good reason I should keep the Teflon-lines?
Any advantages beside that those will live "forever"?
I don't mind changing the rubber-fuel lines every 10 years...
(I have read somewhere that rubber-lines should be replaced at that interval)

So: before making any decisions, it'd be interesting to hear what you engine-guru's are saying about Teflon vs rubber?
(Mel; are you there?? )

Standard fluid lines do typically last for 10 years or more if not disturbed. However, I believe the recommend replacement period is 5 years. And that includes shelf life.
I ran my first standard lines over 10 years, but I don't recommend that. When I removed them they were very stiff. Once they get stiff, they begin to deteriorate.
Personally, I recommend the Teflon lines.

[ao.frog]

Thanks alot for chiming in Mel!

Ok, I'll keep the teflon-lines on my 2nd -7 and on my 2st -7, I'll plan to replace my rubber-lines with teflon as well when they are due for replacement.

I'll also update my maintenace-log to say 5 instead of 10 years for rubber fuel-line replacement.
I didn't think of including shelf-life to those 5 years, so I guess I've some fuel-lines to replace this summer...

[frankh]

Teflon is virtually bulletproof chemically speaking. I have used it almost universally from agressive industrial solvets to 50% hydrochloric acid and everything in between.

I would have no hesitation in using teflon hoses (for 100LL and mogas with or without ethanol) and I bet they have a very long service life (although I don't KNOW what it would be).

Seeing as I have the local hydraulics shop make mine up for next to nothing I could replace them evry year if I wanted to..No point though.

Frank

[Ironflight]

At Oshkosh last year, I asked the two major suppliers of aviation grade Teflon-hose what the lifetime should be (when they would recommend replacement). Both of them said the exact same thing - "That will be determined by the aircraft manufacturer". (Kind of a funny way to respond at an "Experimental" aircraft show, but let's not start that argument...)

The bottom line was that neither would give me any number at all regarding service life, and both suggested that it was not infinite. I'm sure their response was (at least partially) lawyer-driven.

Paul

[RV8RIVETER]

We use either Teflon or stainless lines exclusively at my work. Teflon is used without service life restriction to carry 100% IPA, Acetone, 40% HF acid, 40% hydrogen peroxide, and HCl gas just to name a few. The only degradation I have ever seen is on the furnace gas exhaust lines which carry away process tube acid exhaust from a 1000 deg C furnace. After 5 or more years of that kind of heat they tend to loose flexibility and can crack when moved.

I don't think there is anything to worry about for our applications.

[Kyle Boatright]

I can't think of a single downside to teflon lines.

What have I missed?

[Bavafa]

Is there an easy way to determine which one is Teflon and which is rubber hose? I have used what VANs supplied (less than four years ago). How do I know if it is Teflon vs. rubber since it is covered.

[rocketbob]

Recently I was at the International Motorsports Industry Show here in Indy and I had a look at some of the latest racing hoses and fittings. Goodridge makes a new convoluted teflon hose with black Kevlar jacket that in -6 size it is pressure rated at over 1000psi and has a burst rating of 3900psi. Incredibly light. Google "Goodridge 710".

[TS Flightlines]

sent you a PM.
Tom