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GrassStripFlyBoy

Oil return line clamps

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Noticed a couple of the oil return lines exiting at bottom of cylinders, the 90 degree elbows, are leaking a tiny bit of oil at the hose to elbow joint.  I pushed the hoses a tick further on elbow, then slightly moved the spring clamps on the hose, to perhaps develop a bit more compression.  These spring clamps don't seem real tight, not concerned they are defective just wonder if they weaken over time?  Any foreseeable issues if I swapped these out for a conventional hose clamp?  Could a hose change prior to my ownership have used a slightly different ID / OD that would possibly change the compression force these develop?  Probably safe to swap to a conventional clamp, but always like to cross check these things with those having more experience than me. 

Thanks, Darrell

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Yeah, good point.  Cleary I did not notice that, the slight leakage appeared dirty brown color when I looked at the blue shop towel it was on and I guess my brain saw that as oil.  I'll have to look around further, probably it was coolant then.  

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The aluminum elbow has a flared end. You can feel it under the hose. Make sure the spring clamp is up right by that. Not on top of it. By placing the clamp up next to it it will seal the hose much better and if you have a leak it should go away. Most mechanics just put the spring clamp anywhere on the hose. Sometimes it works and sometimes it doesn't. Moving the clamp up by the flare under the hose will seal it far better.

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I had a small coolant leak.  I did what Roger suggested.... and I switched clamps to the screw worm gear type.  It worked.  I carry an extra clamp in my bag in the plane now.

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That clamp position is exactly as Roger suspected, I had felt the flare and clamp was offset.  I knew it did not belong on top of the flare, but it certainly had room to move over just up to it.  And will consider a conventional hose clamp too.  It's not like there is a "leak", in 10 months and 100 hours my coolant has never had to be filled, and what tiny bit reservoir is down is proportional to the loss I saw over winter cold season when the leaks really develop.  I did an oil change recently and I think pulling the mag plug had some spillage get down into the rad fins which blew traces back into engine area making some oil messes also, so in cleaning that up I was seeing "more oil" when I hit this down tube...  I've been so impressed how tidy this Rotax is compared to my old O-200 that I watch every little for change.  As always, appreciate the inputs.

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59 minutes ago, GrassStripFlyBoy said:

And will consider a conventional hose clamp

FYI Darrell, FD - USA provided the worm style clamp, I did not make the clamp style decision on my own. 

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The spring clamps usually don't have problems when positioned properly, but sometimes during a rubber hose change they can get a little weakened if someone is hard on them during removal. If that happens then you could just buy a new spring clamp or use a Wurth Zebra wormdrive clamp. Do not use the old traditional style that have the slots cut in it like a standard garden hose clamp. The Zebra clamp has raised ribs on it. It won't cut into the hose, it seals better and far less likely to over cam and loosen. 

The Wurth clamp is what FD uses and you already have some of these on your engine hoses.

 

Wurth.jpg

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2 hours ago, Roger Lee said:

The spring clamps usually don't have problems when positioned properly, but sometimes during a rubber hose change they can get a little weakened if someone is hard on them during removal. If that happens then you could just buy a new spring clamp or use a Wurth Zebra wormdrive clamp. Do not use the old traditional style that have the slots cut in it like a standard garden hose clamp. The Zebra clamp has raised ribs on it. It won't cut into the hose, it seals better and far less likely to over cam and loosen. 

The Wurth clamp is what FD uses and you already have some of these on your engine hoses.

 

Wurth.jpg

Thanks Roger.

Right off hand, do you remember the proper size of those for water hoses. I need to order a few.

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I don't know Bill. I'm in the middle of a hose change right now. I'll take a look. I think it is 20mm - 32mm or 25-40?  I'll look.

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5 hours ago, Roger Lee said:

I don't know Bill. I'm in the middle of a hose change right now. I'll take a look. I think it is 20mm - 32mm or 25-40?  I'll look.

Okay, thanks Roger.

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On 7/27/2020 at 6:25 PM, Roger Lee said:

I don't know Bill. I'm in the middle of a hose change right now. I'll take a look. I think it is 20mm - 32mm or 25-40?  I'll look.

These were right. The 25-40mm is for 1" coolant hose and the 20-32 is for 17mm coolant when needed.

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Every Lycoming and Continental engine, factory new, uses worm style clamps however they don't come from Ace Hardware or any other non aviation supplier.  In 47 years I have never stripped one. Some of the clamps are even designed to provide even pressure 360 degrees. Cheap, soft metal, Chinese clamps should never be use on a critical hose, ever.      I am aware Roger doesn't recommend them because some will buy them from Ace Hardware anyway.

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1 hour ago, Madhatter said:

Every Lycoming and Continental engine, factory new, uses worm style clamps however they don't come from Ace Hardware or any other non aviation supplier.  In 47 years I have never stripped one. Some of the clamps are even designed to provide even pressure 360 degrees. Cheap, soft metal, Chinese clamps should never be use on a critical hose, ever.      I am aware Roger doesn't recommend them because some will buy them from Ace Hardware anyway.

The standard OLD TRADITIONAL serrated worm drive clamp used by the old guys (LOL  :) Just teasing ) does cut into hoses more easily and after some of the things I've seen from these guys tightening these style clamps they can strip. That said if applied properly they shouldn't strip.

The Wurth Zebra clamps have no openings so they can't cut into the hose.

" Some of the clamps are even designed to provide even pressure 360 degrees."

I would bet that darn few ever look for the better clamps. To many people a clamp is a clamp.

I still thinks it's better to be on a more progressive side from old school. It's just me. Use whatever clamps you want. :) 

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Most pilots are always looking for "a better mouse trap."

I am included with that crowd. Big fan of anything which makes it more reliable and easier to operate.

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Breeze liner clamps will not cut and have 360 degree even pressure. There are also other clamp options available. There are also some more exotic variations in clamps that have narrow size ranges in mm but  with a very high integrity fastener .  All are aerospace quality. A lot of what I see in light sport is sub standard for certified and that's not to say it's a bad thing however for some items there can be better options if you want them. Most of these clamps are not expensive, just better.

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7 hours ago, FlyingMonkey said:

I know that's just what they cost, but over $20 a foot for rubber hose is highway robbery.

And only one company makes it for Rotax. Conti-Continental. There is NO US equivalent for 17MM. It's either too small or too large an I.D. 

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3 hours ago, Roger Lee said:

And only one company makes it for Rotax. Conti-Continental. There is NO US equivalent for 17MM. It's either too small or too large an I.D. 

That's almost as bad as Garmin.

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