leaking injector connection
 

I have the larger injector lines, and when I first installed them I recall issues with 2 injectors. Leaking at the injector coupling. I finally got them sealed - jiggling/wriggling and cranking harder than I would like on them.
They are leaking again since I had to break the union. Is there anything I can do to improve them? They almost seem to be seating on the lip on the seat on the lines.
Wondered about fine valve paste and trying to seat them better - blocking the injector and line bores of course. Same 2 connectors/injectors as previous. No obvious signs of damage/crud. Did lightly clean the faces with fine wet/dry (1200).
Thanks
Alan

The large Euro lines are rather delicate when it comes to sealing at the injector. They must be tightened with no stress, meaning no bends that mis-align the engagement. They also cannot be overtightened. If overtightened the conical "ferule" will deform and not seal. I've changed out several lines over the years due to this, and even kept extra sets of lines for that purpose. Pulling the lines to test injectors on the engine but outside of the injector blocks is something I never do, as you must bend the lines to do this. Wish I had a better answer for you but I'd buy new lines or have a set of braided lines made.

Thanks Brian - thats what I figured. I have spent a bit of time trying to make sure they are perfectly aligned as far as the seating goes. Tweeked both slightly. They both gave me issues when I first installed them. Now that I have had to break the seal, I am back to that point.
Tell me about the braided lines.
Thanks
Alan

Hi Alan,
I had the very same issue with my fuel lines at the injectors (there were 2 leaking). I had slightly bent several lines in taking them on and off when I redid my CIS. After messing with things a lot, they were still leaking. So I did a bunch of research and came up with this solution:

I used very thin copper conical sealing washers. These worked marvelously and all my lines have been leak free for going on 2 years now. I used 4AN Seco7 Copper washers from Pegasus Racing:

3202-04-COPPER SECO 7 Seal - 4AN, Copper

These are paper thin and are used in the aviation industry for similar issues. You just have to be pretty careful and precise when laying them on the fuel injector mating surface. Get everything aligned with the washer (so the bore of the fuel injector is centered in the washer hole) and carefully place the fuel line on and gently tighten the line and then snug it down. You don't want the washer to move and plug the fuel injector inlet hole!

For safety and to satisfy my own paranoia, I bought a dozen of the washers so I had spares. I did several test runs where I placed the washer on the injector and then placed the fuel line on and tightened everything down..... then I unscrewed the fuel line and took it back off to make sure the washer was still in place and not wrinkled up in the fuel injector bore. Everything was still intact and the washers were still aligned perfectly in these test runs.

Again, these "washers" are paper thin and are designed to seal any tiny surface imperfections, distorsions, etc. They have worked great for me.

Hope this helps- Lord know you helped me in tuning my CIS after I got it all back installed!

Keith

Here's a link to the online page:

https://www.pegasusautoracing.com/productselection.asp?Product=3202

Wow - that is awesome.
Thanks so much.
I will track some down and order them - like you - a dozen. I have tweeked my injector lines - could see a 'slight' misaligment from the perfect angle. But these will be great.
Thanks again.
Alan

Ordered.
3 cheers for Pegasus racing.
And thanks for the help. Awesome
Alan

Great- I hope they work well for you like they did me!

Super helpful.
Thanks again. Don't like cranking hard on that stuff. Has to be a better option.
I guess your CIS tuning turned out OK?
Regards
Alan

Nice find!
What size is correct for the euro lines?

Those should work well, here is another brand, DEL aerospace available at aircraft spruce. I was looking for a similar product but metric and can not find one, from what I have seen metric hydraulics use different angle than 37 deg, but that seal should form easy enough. With all the personal helicopters in NZ must have some parts/service around, they would likely have these fittings in a pinch.

4AN is the correct size for the euro lines. ��

Thats a relief - but I would have just ordered another size if wrong.
908/930 - yes - now I know where to look - that may work. But whether the right size, Al or Cu etc, prob just as easy to order from Pegasus. Yes the freight is more than the item - but I would probably have the same issue at this end anyway.
I have a mate who is a chopper tech - so will ask around.
Thanks
Alan

wcarson is a DIY Porsche God! this worked perfect!

I’m glad it worked well for you!

The 4an copper seals work they are paper thin buy extra. i used a little bit of grease to hold them in place. while aligning them.