jdeas

jdeas

Well Known Member
Guys,
What is the proper way to seal AN fittings on the engine? On my gas lines I have been using anti-seize on the threads as I make my connections but what about fittings on the engine itself?
I.E. I have two loose AN fittings (oil returns) on the cylinder heads. Given the heat should I use 'EZ Turn Lube' on the side that screws into the head?
Instead of teflon tape, can I use the same stuff for all the oil plugs (1/2" pipe fittings)?

* IO-360 Engine
 
If its a tapered NPT pipe end, use a pipe thread sealent like easy turn or Loctite PST. I would not use teflon tape on ANYTHING on an aircraft...or boat or car. The 37 degree AN fittings should be assembled dry. I have the PST 678 at the shop if you need it.

Mike
 
G-force said:
If its a tapered NPT pipe end, use a pipe thread sealent like easy turn or Loctite PST. I would not use teflon tape on ANYTHING on an aircraft...or boat or car. The 37 degree AN fittings should be assembled dry. I have the PST 678 at the shop if you need it.

Mike
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I would disagree with the "no teflon tape". A year ago I decided to put rector seal, teflon paste, teflon tape, and RTV on a tray and let them soak for 2 days in 100LL. After 2 days all became runny except for the tape. The tape actually held up.:eek:
 
The PROBLEM with tape is........

that it is all too easy to get a small bit of the tape in the system, whether it's oil, fuel, or hydraulic. Then you stand the chance of plugging up a small orifice with the teflon tape. Most people will NOT use teflon tape on threads in aircraft fluid systems, for that reason.
 
Sticky1 said:
I would disagree with the "no teflon tape". A year ago I decided to put rector seal, teflon paste, teflon tape, and RTV on a tray and let them soak for 2 days in 100LL. After 2 days all became runny except for the tape. The tape actually held up.:eek:
Click to expand...

The problem with using tape is the chance of getting a small "tail" of tape inside the engine. If this happens, (and believe me, IT DOES HAPPEN!) it can create havoc.
I have been using Permatex form-a-gasket #2 on pipe thread fittings on engines for over 50 years with no problems.
 
Teflon tape - NOT

Sticky1 said:
I would disagree with the "no Teflon tape". A year ago I decided to put rector seal, Teflon paste, Teflon tape, and RTV on a tray and let them soak for 2 days in 100LL. After 2 days all became runny except for the tape. The tape actually held up.:eek:
Click to expand...

Sticky,
Teflon tape has been known to have caused forced landings due to small pieces working their way between the carburetor needle and seat, or into a fuel injection servo.
Better to use a sealant like those mentioned above. I also like Permatex Thread Sealant with Teflon (it's a paste, no tape in it)
You are correct that gasoline will dissolve RTV. NEVER coat any gasket in the fuel system with RTV.
Charlie Kuss
 
Let's be clear

When I went to A&P school 20 years ago (ugh) I learned that the pipe thread portion could be sealed with approved pipe sealant (like form-a- gasket), but the flange part should be assembled dry. If the flange part is prone to leaking, then a "voshan" could be used on the flange. A "voshan" is a aluminum or copper piece of sheet metal (like a washer) that is shaped to fit over the flange and goes between the flange and the tubing. I was told to never use teflon tape of sealant on the flange part of the fitting.
 
No Tape

Glad to hear it. I had a tail get into a brake system years ago and clog the restrictor . Swore I would never use it again.
EZ Lube it is.

Thanks everyone.
 
THREAD SEALENT does more to lube the threads so they can be properly tightened. That is why teflon has been popular. The teflon does not really seal anything. But it does allow the threads to make the seal.

The same threads that you use for your 5 psi fuel lines (40? for fi) are the same threads used on 2000 psi HYD and GAS fittings.

Take a piece of threaded 3/4" pipe and thread a coupling (dry) on the pipe. Use your pipe wrench and get it as tite as you can. Place a mark on the pipe and the coupling and then remove the coupling. Now do it again but this time, use you TEFLON pipe dope and see how far past the mark that you go. That extra amount is what will keep the fitting from leaking.

Our 1/8 and 1/4" fittings that we use will require far less force than what is used in the above example................
 
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