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Lycoming leaky cylinder oil return lines

whodja

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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.
 

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Price

Looked at site couldn’t find. What was cost for a set for your engine.

Thanks
 
Hi All---we havent updated the website to include these drain hoses YET----Steve has been alittle overwhelmed the past several weeks getting ready for Osh.
Those that may be interested, email me and I'll quote you. Yes, does come with the case fittings.
Tom
 
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.
 
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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.
 
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.
 
Clamp size?

What size clamp do you need for the return lines? It looks like the 17mm clamps would work for the specified hose.
 
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TS Flightlines

I'm saying goodbye to the chronic leakers as I just ordered my new lines from Tom. I've never been sorry for purchasing the BEST.

Ron B.
 
solving return line leaks

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.
 
For those wanting to stay with the rubber connections, try these instead of worm clamps. Spreads the sealing over a wider area than a spring clamp.
Might have to make a "custom" set of pliers to install them.

Tom
 

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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.

I use 3/8" Fuel injection hose from the auto store with constant tension clamps. 7 years and 800 hours on the 6 and still look brand new. The FI hose is designed to be impermeable to fuel vapor. Oil is pretty much the same, but thicker (all comes from the same crude stock). Regular fuel hose is permeable and can let oil leach through over time.

Larry
 
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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.

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'! :)
 
Joe---they kinda are. Check the OE aluminum tubes, they are flat as they connect to the rubber hoses.

Tom
 
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.
 
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.

Lycoming SSP-1776 has the torque spec that Lycoming recommends.
Screen Shot 2022-08-08 at 5.53.51 PM.png

When I have not been able to find the Lycoming value quickly, I would just use AC43.13-1B values till I can find the Lycoming value. (They just so happen to be the same in this case.)
Screen Shot 2022-08-08 at 5.49.22 PM.png
 
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!
 

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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.

20140626_172913.jpg
 
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

What diameter clamp did you use?
 
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'! :)

I'm glad someone else mentioned this. The oil return lines are gravity-fed and should run continuously downhill to the sump connection.

Its funny, I've worked on houses where people installed sewer lines with a sag/low point too. Doesn't work very well.
 
What diameter clamp did you use?

17mm. @WJB used 3/4", or 19mm.

The main thing to remember is clamp size is based on the outside diameter of the hose. The Gates Power Steering Return hose that I keep recommending needs 17mm or 21/32 clamps from McMaster. If you use a different hose like @WJB used, would be best to measure the OD first.

I just happened to be doing an oil change today and shot the same pic I had attached earlier, except now the hose has been in use for 15 years and 981 hours. Still looks like new.

20220915_152422.jpg
 
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
 
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

Yeah, that's a good point. While Tom's hoses are beautiful and high quality, there's a high potential to install them with a built-in "P-trap" as the OP's photo showed. And how would you support the hoses to keep a constant downward slope? There's not much down there to use as a hose support. I suppose you could zip-tie them to the baffle tie wires? Of course you'd have to use silicone self-fusing tape to keep the zip ties from sawing through the hoses.

All that said, when I overhauled my 2000-hr-since-new engine, I inspected and cleaned the original aluminum tubes, and there was very little residue in the bottoms of the tubes. So the original tubes being flat isn't so bad.

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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.

With the MIL6000-6, a full 3/4" OD, 17mm clamps were too small and I couldn't get them open enough to wiggle over the hose. The 3/4" I used were expanded 50-60% of their full range when "let go". The MIL6000-6 hose, too, is quite a bit stiffer than the stuff Lyc put on originally, so deformation is less (not sure what hose hgerhardt used)

It was quite tight when I bench tested it prior to install .. we'll see how it works! Pretty easy to fix if not. Surely better than the sieve that Lyc put on originally.
 
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