This from an old thread. I just changed my leaky lines to this. Works so far > https://vansairforce.net/community/showpost.php?p=1185599&postcount=3
The key to making the standard lycoming drain lines work and not leak is to stop using screw type hose clamps on the coupler hoses.
If you install brand new hose with constant compression spring clamps they will not leak.
The problem is the expansion and contraction with heating and cooling that the tubes experience makes the hoses get loose on the tubes with the screw clamps. The constant compression clamps expand and contract with the line therefore preventing them from beginning to leak.
Oops. I see Keith already provided the tip.
Is there a part number for the constant tension clamps?
-Marc
The key to making the standard lycoming drain lines work and not leak is to stop using screw type hose clamps on the coupler hoses.
If you install brand new hose with constant compression spring clamps they will not leak.
The problem is the expansion and contraction with heating and cooling that the tubes experience makes the hoses get loose on the tubes with the screw clamps. The constant compression clamps expand and contract with the line therefore preventing them from beginning to leak.
Oops. I see Keith already provided the tip.
I second this. I did this too. Very simple, extremely cheap, no mods and very effective.
1 ft of MIL6000-6 oil hose (3/8” ID), and some 19mm constant tension clamps (8x) solved my leak issues. The MIL6000 hose is thicker walled, and made for oil use. Seems to be holding up better than the thin walled Lycoming or Superior hoses used previously. Also ended up buying a tool to install them….but hey, I can use it for the ones on my cars too.
TSFlightlines makes a kit of perfect fit oil return lines. After tightening the hose clamps regularly I finally eliminated the constant oil leaking from the hose transition. Very well made.
In the process of changing out my screw clamps for new hose and constant tension clamps.
That said, for the blue 6d female aluminum fittings that connect the aluminum return lines to the blue 6d male aluminum fittings on the cylinder, what should I retorque those to when reinstalling? I’ve never been able to find consistent guidance on those aluminum fittings.
Thanks.
My oil return hoses started to seep at about 100 TTSN ... tightening the band clamps never seems to work, they only dug in deeper into the hose and drip drip drip!
I used the following HW:
3/4in constant tension clamps (https://www.mcmaster.com/7329K13/)
MIL6000-6 hose (ACS)
Worked great! I thought it would be a real PITA to get in under the cylinders with the snorkel and other HW in the way, but there was actually lots of room. I kept the clamps open with a small set of needle nose vice grips, slid them in place and carefully released the clamp. Resetting and adjusting the clamps was easy, also.
Thanks for the great tip!
I sincerely hope those clamps work out for you long-term. To me, they look about one size too big for the diameter of the hose. Below are what mine look like. Notice how close my spring ears are to each other compared to your installation. Notice also how your clamps show hardly any indentation on the hose, indicating low clamp force.
View attachment 30872
Those look terrific, but I have one question...shouldn't those lines be "downhill" all the way? The oil return isn't under pressure, so the lowest point could collect oil which might get "sludgy" over time?
Just asking'!
What diameter clamp did you use?
Steve- if you look at Heinrich's and the OE tubes, as they get close to the rubber connections, they are flat and go directly into the rubber, not angled downward. Thats what we based our hoses on, BUT as a hose you 'can' change the routing so it has a slight downward slope to the hose end.
Tom
I sincerely hope those clamps work out for you long-term. To me, they look about one size too big for the diameter of the hose. Below are what mine look like. Notice how close my spring ears are to each other compared to your installation. Notice also how your clamps show hardly any indentation on the hose, indicating low clamp force.