Flexible Oil Pressure Line

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Flexible Oil Pressure Line

Postby C170U2 » Fri Feb 20, 2015 2:55 pm

Has anyone changed their copper oil pressure line out for a flexible line? I'm thinking stratoflex 311-2N hose. I did a search but couldn't find a write up on someone doing this. I found some info on the 120/140 site but not much here. I've never made a hose before, but with Skyranch out of business I am going to give it a try. I hear one of the problems is that they don't make a mandrel for the -2 hose. Can someone post a picture of their homemade mandrel?

Thanks!
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Re: Flexible Oil Pressure Line

Postby daedaluscan » Fri Feb 20, 2015 3:58 pm

I have a flexible rubber hose from the engine to the firewall, but I am afraid that I do not have a photo.
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Re: Flexible Oil Pressure Line

Postby DaveF » Fri Feb 20, 2015 4:20 pm

I fabricated a fuel pressure sense hose with Aeroquip 193-2 and can attest to the fact that a mandrel is at least a good idea. I had no mandrel and got a small flap of rubber at each end, just like they warn you about. The worst part was that the flaps weren't obvious, but they acted like check valves in the hose and caused bad fuel pressure indications.

Here's a thread on small hoses.
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Re: Flexible Oil Pressure Line

Postby bagarre » Fri Feb 20, 2015 4:51 pm

I made mine up two years ago.
I couldn't find a -2 mandrel so I made one up with a -2 fitting and a 1/8th or 1/16th drill bit (back side). Cant remember the exact size drill bit.

http://www.cessna120-140.org/forum/viewtopic.php?t=2112

A good time to verify you have a small orifice fitting on the engine block as well.
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Re: Flexible Oil Pressure Line

Postby GAHorn » Fri Feb 20, 2015 5:37 pm

There are alternatives.

The Official Cessna Part Number for the C-150 hose: 359-2D0150 This hose is 15" long, and may be a bit short for many 170's (the 150 at the end of the pn-sequence indicates 15" length, a 359-2D0190 would likely be much better at 19") , the one on my airplane was acquired from Del and is the same as that for a Bonanza, about 17" long. He will likely recommend one 19" long. Last I checked, Cessna gets about $60 for it.

In 2008 (so prices may have changed), In an email exchange from Del Lehmann, Mountain Airframe Services, Mena, AR (who supplied my rubber oil pressure hose):

"I wouldn't recommend getting it from Beech$$$$$.

The generic PN# for the hose is 193000-2D-0160. For your info the 193000 denotes material, 2 inside diameter (in 16ths), D aluminum fittings, 0160 length (16"), -0236 would be 23.6" long. An "F" inserted after the 193 (193F000) gets firesleeve.

My cost ranges from $41-$49. I don't know if any of the above sources will extend any discount (list ranges from $75-90) to a private owner. For $60 check in the mail, I can order and drop ship to members who are interested."

Ordering one from him might be a real simple answer to the situation because you'd have a hose with an approval basis/datatag (and could even get it firesleeved if desired.)
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Re: Flexible Oil Pressure Line

Postby shortfielder » Fri Feb 20, 2015 11:46 pm

A side note here to a similar situation. I have the 180hp conversion, so I have an electric fuel pump and fuel pressure gauge in the panel. I have a copper line from the firewall to my fuel pressre gauge. I think it would be a good idea to replace that with a flex line also.
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Re: Flexible Oil Pressure Line

Postby Bruce Fenstermacher » Sat Feb 21, 2015 12:14 am

What! :o 8O

You haven't polished that copper line yet. What are you waiting for. 8O

How could you think of removing something that could be brought to a brilliant shine like the rest of your plane. :wink:
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Re: Flexible Oil Pressure Line

Postby shortfielder » Sat Feb 21, 2015 12:27 am

:>))) Shine, on my plane???
Nice rubber flex line with some tin foil on it, shiny side out :wink:
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Re: Flexible Oil Pressure Line

Postby flyboy122 » Sat Feb 21, 2015 2:37 pm

My plane has the Avcon Lycoming conversion, and has flex lines for both oil and fuel pressure. Works fine.

ALWAYS check for a rubber flap after building a line, even if you use a mandrel. A hemostat (sp?), commonly used by fishermen to remove hooks, works great for going in and snagging that flap out on bigger lines. I always twist the line and check as well. I've had obstructions that laid flat when the line was straight, but popped up when you put a bit of twist or bend in the line. Learned that one the hard way. :('

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Re: Flexible Oil Pressure Line

Postby bagarre » Sat Feb 21, 2015 4:04 pm

Since this hose is under pressure, is it required to have a fire sleeve by modern standards?
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Re: Flexible Oil Pressure Line

Postby GAHorn » Sat Feb 21, 2015 6:44 pm

I don't think it's mandated by rule for our planes, but any flammable line fwd of the firewall is a good idea.
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Re: Flexible Oil Pressure Line

Postby DaveF » Sun Feb 22, 2015 3:42 am

gahorn wrote:I don't think it's mandated by rule for our planes, but any flammable line fwd of the firewall is a good idea.

Agree. For oil- or fuel-carrying hose I use Teflon hose with integral molded firesleeve, like Aeroquip AE466 or Stratoflex 101.

Regular Stratoflex firesleeve works fine, too, but I like the clean molded firesleeve, the tighter allowable bend radius, and the ability to specify color -- blue for fuel and brown for oil.
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Re: Flexible Oil Pressure Line

Postby lowNslow » Sun Feb 22, 2015 2:26 pm

DaveF wrote:
gahorn wrote:I don't think it's mandated by rule for our planes, but any flammable line fwd of the firewall is a good idea.

Agree. For oil- or fuel-carrying hose I use Teflon hose with integral molded firesleeve, like Aeroquip AE466 or Stratoflex 101.

Regular Stratoflex firesleeve works fine, too, but I like the clean molded firesleeve, the tighter allowable bend radius, and the ability to specify color -- blue for fuel and brown for oil.

What size did you use for the oil pressure line, I notice the Aeroquip only goes down to a -4 and the Stratoflex to a -3?
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Re: Flexible Oil Pressure Line

Postby wingnut » Sun Feb 22, 2015 3:22 pm

Hose options have changed in recent years. I can't remember which, either Aeroquip or Stratofex stopped making #2 hose. Even #3 hose has limited material options. I had a #2 mandrel up until a few years ago, now I can't find one. A few years ago I tried to get enough interest among members to get a quantity discount, but only got 3 or 4 orders.
If you want/need a flex hose, check out Precision Hose Technologies, Tulsa OK.
They have a good website that explains the materials, what the numbers and letters in the part number denote, and how to measure for proper fitment and choosing fitting styles ( straight, 45*,90*, swivel,etc).
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Re: Flexible Oil Pressure Line

Postby DaveF » Mon Feb 23, 2015 3:25 am

Sorry, Karl, I wasn't clear about that. For the fuel pressure sense hose I used plain old Stratoflex 193-2. I firesleeved it with some slip-on silicone coated fiberglass sleeve from Spruce. I've never seen -2 size integral firesleeve hose.

Precision Hose Technology says this about 193-2:
NOTE: Beech, Cessna and Piper used this hose for fuel, oil and hydraulic drains. Also, in some aircraft, 193 hose assemblies were used for engine fuel pressure and oil pressure.

When I bought a hose from PHT I made the mistake of asking about an Aeroquip hose. "We're a Stratoflex shop!" was the irritated reply. I guess it's like asking for Mopar parts from the Ford dealer.
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