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Loose Intake Hose Clamps

Pilotjim77

Well Known Member
I pulled the cowling yesterday while chasing some wires, and I found that three of the eight clamps on the intake hoses were pretty loose. Each intake hose has two different kinds of clamps; the inner clamps closest to the sump have wing type screws that you can turn with your fingers. The outer clamps have hex/slotted screws. Only the inner clamps with the wing screws have become loose.

I am thinking I should replace the wing screw clamps with hex type clamps. Seems like I could tighten them down quite a bit more. Maybe that's why they are coming loose? Any thoughts?

Thanks in advance!

Jim
 
?Wing? style hose clamps take a slotted tool driver bit to tighten beyond finger tight. They will stay tight. With good access, pliers work. Not a normally used clamp. My ?56 182 has some.

R
 
I made a tool to tighten these clamps some tears ago out of a piece of steel tubing. The tubing was heated, one end nearly flattened to fit the clamp, and the other was squared to fit a 3/8" extension.

Cheers, David
RV-6A A&P
 
I replaced all of my clamps with the smooth T-Bolt clamps. I hope they do a better job than the old wing clamps.
 
The problem is that the hoses are always shrinking.... so what ever traditional clamp you installed will keep getting loose because of the hose shrinkage. It is not because the clamps are loosening.
Constant tension spring clamps are the way to go.

If you upgrade to the SDS intake kit
lycflange222.jpg


You get spring clamps with it.
 
Over torquing is to be avoided as it causes "cold flow" of the hose, a permanent deformation of the hose. It also damages the clamp. The table of limits in the Lycoming overhaul manual specifies the torque for worm drive clamps.

Ed Holyoke
 
AND you get the benefit of actual seals at the intake, replacing those ^&*(% paper failures... which is what the kit is about.
 
I pulled the cowling yesterday while chasing some wires, and I found that three of the eight clamps on the intake hoses were pretty loose. Each intake hose has two different kinds of clamps; the inner clamps closest to the sump have wing type screws that you can turn with your fingers. The outer clamps have hex/slotted screws. Only the inner clamps with the wing screws have become loose.

I am thinking I should replace the wing screw clamps with hex type clamps. Seems like I could tighten them down quite a bit more. Maybe that's why they are coming loose? Any thoughts?

Thanks in advance!

Jim
Not sure what you're actually using, but a general purpose stainless steel worm-drive hose clamp does fine. They will likely loosen a little over time. Just check them every 100 hours or so. 1/4 or 1/2 turn of the screw to snug them up. Or, spend a chunk of money and not worry about checking.
 
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Actually, constant tension clamps are a comparable cost to the old school worm clamps, but the CT versions work better.

The value of the SDS kit is at the other end of the tube. NOTHING stops the paper composition gaskets from failing eventually, so the permanent fix is the O ring and retainers Ross sells.
 
Not sure what you're actually using, but a general purpose stainless steel worm-drive hose clamp does fine. They will likely loosen a little over time. Just check them every 100 hours or so. 1/4 or 1/2 turn of the screw to snug them up. Or, spend a chunk of money and not worry about checking.

Actually, constant tension clamps are a comparable cost to the old school worm clamps, but the CT versions work better.

The value of the SDS kit is at the other end of the tube. NOTHING stops the paper composition gaskets from failing eventually, so the permanent fix is the O ring and retainers Ross sells.

^^^^^^^
THIS

I should have expanded a bit more in my previous post. The context I meant to convey with my recommendation, but obviously didn't since I didn't even mention it, is that leaks at the coupling hoses are only one of the potential issues with the Lycoming induction system.
If all someone wanted to so was resolve the issue at the coupler hoses, you could buy just the C.T. clamps.

The benefit of the total kit is to virtually eliminate any chance of a leak at the cyl. ever happening.
That is the reason I installed it on my airplane.

BTW, constant tension clamps on the oil return tube coupler hoses is a good idea as well. Pretty much eliminates the oil leaks that are always occurring there as well.
 
BTW, constant tension clamps on the oil return tube coupler hoses is a good idea as well. Pretty much eliminates the oil leaks that are always occurring there as well.
Just the typical automotive store variety or is there an "aircraft grade" version that we should be looking for? I've always had a bit of oil weep on my return lines so I think this would be a good upgrade.
 
I've used the auto parts store CT clamps on my oil return lines with great success. Just the flat style packaged with canister style fuel filters. Common as dirt.
 
Thanks all for the replies. I will try just snugging these up and see how it works. I did try one with pliers, but it wanted to slip back away from the sump, almost as if the intake hose were cone shaped.

I will also take a look at the constant tension clamps.
 
Thanks all for the replies. I will try just snugging these up and see how it works. I did try one with pliers, but it wanted to slip back away from the sump, almost as if the intake hose were cone shaped.

I will also take a look at the constant tension clamps.

It is not unheard of, that when coupler hoses get installed, the installer doesn't get them positioned correctly so that they are barely on the induction tube or the stub tube on the sump. I have seen this at least a couple of times.
When this happens, tightening the clamp can make the hose try to squirt off of the connection on one end.
 
It is not unheard of, that when coupler hoses get installed, the installer doesn't get them positioned correctly so that they are barely on the induction tube or the stub tube on the sump. I have seen this at least a couple of times.
When this happens, tightening the clamp can make the hose try to squirt off of the connection on one end.

Thank you Scott. I will take a look at that.
 
Intake kit

Just looked around the SDS website and couldn?t find pricing or ordering info. Thinking about doing this at the next annual, anyone have a direct link to this product & pricing info?
 
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