Pressure transducer fitting size? 78J

[Jocbay]

Oil or fuel.  I'm ordering a JPI 900 engine monitor and the choices are 7/16" or 3/8".  I can't get hold of my mechanic and a search turned up nada.  Anyone know?

[carusoam]

Sometimes…. The guy with the most JPI answers is @Jeev…

He is out in the Vegas area…

Best regards,

-a-

[Guest]

The EDM 900 for my Comanche just arrived, the pressure transducers threads are 1/8”-27 NPT.

Clarence

[PT20J]

Fuel pressure and oil pressure transducers connect to hoses with 3/16" flare fittings. Not sure if there is room to get a fuel pressure transducer attached directly to the servo; there might be enough room to get the oil pressure transducer directly on the accessory housing. The hose might provide some useful damping due to trapped air. 

Skip

[Ragsf15e]

30 minutes ago, PT20J said:

Fuel pressure and oil pressure transducers connect to hoses with 3/16" flare fittings. Not sure if there is room to get a fuel pressure transducer attached directly to the servo; there might be enough room to get the oil pressure transducer directly on the accessory housing. The hose might provide some useful damping due to trapped air. 

Skip

The jpi install manual recommends not installing them directly to the engine itself.

Both you and Doc are right as the engine connection point is 1/8” npt.  That typically connects to mil spec hoses using the 3/16” JIC flare pipe fittings.  The transducers jpi used also have a flare fitting.  
 

I know this because the snubbers that jpi recommend have the npt threads (no flare) and you either have to install them directly into the engine npt fitting or have appropriate adapters.  I recently bought a bunch of female/male npt / jic adapters and put snubbers on both oil and manifold pressure.  Smoothed everything out real nice.

[Ragsf15e]

13 hours ago, M20Doc said:

The EDM 900 for my Comanche just arrived, the pressure transducers threads are 1/8”-27 NPT.

Clarence

You must have different ones than my edm 930.  I have the magic $400 i2s transducers that use the flare fitting.

Maybe you have the vdo transducers?

Edited July 27, 2021 by Ragsf15e

[Guest]

Oil pressure is a 1/4” hose, fuel pressure is a 3/16” hose.

[Guest]

10 minutes ago, Ragsf15e said:

You must have different ones than my edm 930.  I have the magic $400 i2s transducers that use the flare fitting.

Maybe you have the vdo transducers?

I’m going to build a manifold to install all of the transducers, then run hoses from the engine to the transducer manifold.

Clarence

[PT20J]

12 minutes ago, M20Doc said:

I’m going to build a manifold to install all of the transducers, then run hoses from the engine to the transducer manifold.

Clarence

P is misaligned Just kidding. It’s a thing of beauty and the kind of craftsmanship only an owner would provide. 

[Guest]

1 minute ago, PT20J said:

P is misaligned Just kidding. It’s a thing of beauty and the kind of craftsmanship only an owner would provide. 

It was a prototype built for a Mooney!  I’ve built a few more since then, each one an improvement over the last.

Clarence

[PT20J]

18 minutes ago, M20Doc said:

Oil pressure is a 1/4” hose, fuel pressure is a 3/16” hose.

Hmmmm. When I replaced the hoses on my engine I looked at the tags on the old ones and didn’t check the IPC.

Oil pressure: 124F001-3CR0170

Fuel pressure: 124F001-3CR0290

Both 3/16.

Skip

[PT20J]

1 minute ago, M20Doc said:

It was a prototype built for a Mooney!  I’ve built a few more since then, each one an improvement over the last.

Clarence

Well, then it’s appropriate. Mooneys are cut to size, beat to fit, paint to match, no two the same. 

[Ragsf15e]

1 hour ago, M20Doc said:

I’m going to build a manifold to install all of the transducers, then run hoses from the engine to the transducer manifold.

Clarence

Yes, that’s much better than having them placed randomly around the engine with clamps.

[Ragsf15e]

1 hour ago, PT20J said:

Hmmmm. When I replaced the hoses on my engine I looked at the tags on the old ones and didn’t check the IPC.

Oil pressure: 124F001-3CR0170

Fuel pressure: 124F001-3CR0290

Both 3/16.

Skip

Mine were also the same size.  Interesting.  All the transducers are the same size, so if they start out different coming out of the fuel servo / engine, there must be an adapter to get them to the same size line somewhere.

[PT20J]

1 hour ago, Ragsf15e said:

Yes, that’s much better than having them placed randomly around the engine with clamps.

Mooneys must have 500 lbs of Adel clamps. I hate Adel clamps. Whoever Adel was, he hated maintainers. 

Skip

[Ragsf15e]

36 minutes ago, PT20J said:

Mooneys must have 500 lbs of Adel clamps. I hate Adel clamps. Whoever Adel was, he hated maintainers. 

Skip

Definitely agree.  I’ve seen someone else on here that has it set up like Doc’s.  It’s way better.  Mine was done before I got it, but the MP Transducer is actually inside the firewall just behind the edm930.  The other two are at least in the engine compartment, but not very accessible.  I would really like the brackets and snubbers cleanly arranged and accessible, but it’s probably not worth it until the engine is off for a rebuild someday.  It’s really hard to take something apart that’s been working fine for years.  Almost guaranteed to break it.

[Ragsf15e]

On 7/27/2021 at 3:53 AM, M20Doc said:

The EDM 900 for my Comanche just arrived, the pressure transducers threads are 1/8”-27 NPT.

Clarence

I’m still trying to get my head around this…. Isn’t this page from the installation manual saying the oil pressure transducer had flared fittings?

[PT20J]

Think I figured it out. Here’s a picture of the transducer from the Aircraft Spruce website. The transducer has a pipe thread and comes with a flare adapter. 

Skip

[Jocbay]

Thanks for the replies everyone.  Much Appreciated.

[Ragsf15e]

3 hours ago, PT20J said:

Think I figured it out. Here’s a picture of the transducer from the Aircraft Spruce website. The transducer has a pipe thread and comes with a flare adapter. 

Skip

That makes mounting a snubber easier as they are npt fittings.  You could attach a snubber directly to the transducer and then the supplied fitting.  Not sure why some need to add a snubber and some don’t, but that definitely smoothed out my indications.