Adapter materials question

[BDofMSP]

Odd question.

I need to adapt an M22 x 1.5 hole in my manifold to hold a 1/4" NPT stainless turbo boost pressure sensor. I have limited clearance and need to adapt to a 90 degree, so I would prefer to use an M22 (male) to 1/4 (female) bushing, and then a 1/4 to 1/4" 90 degree adapter.

Note - this thread adapter is called a bushing but it's not what I usually think of as a bushing. But we're going with it since that's what they called it. It's just a thread adapter.

I can find that bushing, but only in carbon steel. The 90 adapter is brass. Again the sensor is stainless.

I can find the bushing in brass, but only M22 to 1/8". I'd have to adapt up to 1/4 and I don't know how that would impact my pressure readings.

So do I care that the bushing is carbon steel? I'm assuming that manifold is cast iron? Or would I be better off using brass, but having to adapt from 1/8" to 1/4" for the sensor?

For the visual, I'm trying to replicate this piece (which I'd buy but it's 1/8 NPT instead of 1/4).

Thanks
BD

 

[TWedd]

I don't think the 1/8" fittings will affect your pressure readings. If you used a 1/8" elbow, would that allow you to point it in a direction that would give you more room to make the adapter fittings?

 

[BDofMSP]

Yes a 1/8 to 1/4 elbow would work if it doesn't mess with the readings. I was concerned that the pressures would change as they transition from one to the other. Perhaps not. I've never claimed to be a scientist. Or even that smart.
BD

 

[RT Firefly]

Greetings,
Mr. BD. A restriction in the "line" may affect the instantaneous reading and create a lag in the gauge but it also may be so slight as to be unnoticeable. My $.02.

 

[Solly]

Air pressure won't change. Your thinking air flow. There is no flow to, by, or thru a gauge sensor. It just sits there and measures the amount of pressure in the space.

 

[BDofMSP]

Thanks. Once again I'm reminded of how fortunate I am to have knowledgeable resources at my finger er, thumb tips.

This should be easy. Thanks much.
BD

 

[Bacchus]

You can also go M22 x 1.5 to 3/8" NPT bushing and then a 3/8" Male NPT to 1/4" Female NPT elbow - both in brass. That should be neat, simple and minimum projection.

https://www.fittings.space/fittings...ead & Adapters&nR[visibility_catalog][=][0]=1

https://www.amazon.com/Litorange-Me...t=&hvlocphy=1022735&hvtargid=pla-836591380230

 

[Comodave]

I am not an engine mechanic by any means, but don’t you want steel fittings going into the engine so the vibration doesn’t crack them?

 

[BDofMSP]

You can also go M22 x 1.5 to 3/8" NPT bushing and then a 3/8" Male NPT to 1/4" Female NPT elbow - both in brass. That should be neat, simple and minimum projection.

https://www.fittings.space/fittings...ead & Adapters&nR[visibility_catalog][=][0]=1

https://www.amazon.com/Litorange-Me...t=&hvlocphy=1022735&hvtargid=pla-836591380230

I just saw 1/4 to 1/4 or 3/8 to 3/8 there. I can look around though. Thanks
BD

 

[BDofMSP]

I am not an engine mechanic by any means, but don’t you want steel fittings going into the engine so the vibration doesn’t crack them?

Great question. I have no idea. Perhaps someone will chime in.
BD

 

[C lectric]

The pressure reading won't be affected UNLESS there is flow though it. That should not be the case here. Use the 1/8 ftg.

I almost allways use steel hydraulic fittings on the engine for their resistance to cracking under vibration.

 

[RT Firefly]

Greetings,
Mr. S. "Your thinking air flow." In essence, aren't there 2 "areas" connected by the fitting Mr. BD is looking for? One "area" being the turbo and the other the sensor. IF the fitting had an orifice of, say, .001" there would be a lag while the pressure in the two areas equalized THROUGH the fitting wouldn't there?

 

[jleonard]

The pressure reading won't be affected UNLESS there is flow though it. That should not be the case here. Use the 1/8 ftg.

I almost allways use steel hydraulic fittings on the engine for their resistance to cracking under vibration.

Yes steel hydraulic fittings are preferred.

 

[Solly]

Greetings,
Mr. S. "Your thinking air flow." In essence, aren't there 2 "areas" connected by the fitting Mr. BD is looking for? One "area" being the turbo and the other the sensor. IF the fitting had an orifice of, say, .001" there would be a lag while the pressure in the two areas equalized THROUGH the fitting wouldn't there?

Probably...Would it matter in this case ? Probably not...….
1/8 or 1/4 in. fitting, I don't think the gauge would be accurate enough to show the difference.
But I'd say it would be OK for Gov. work.


Am I an expert? Certainly not. No good at splitting hairs either.
When I had them I couldn't see them.

 

[EngNate]

No flow, no pressure change. Check McMaster Carr Supply also for metric/npt adapters

 

[BDofMSP]

McMaster was the first place I checked. The do not have an M22 adapter.

The only parts I could find are brass so they've been expedited. I'll keep looking for steel replacements.

Thanks,
BD

 

[BDofMSP]

I can share that brass did indeed fail, but because of my stupidity. When I installed the brass fittings the sensor wouldn't clear the manifold. But if I just turned it another quarter turn, it had plenty of clearance!

Well it didn't have another quarter turn in it, and snapped off. I spent the rest of the day drilling out the broken fitting, tapping out the residual pieces, and driving into the closest thing to a city around here to find a substitute. Which was just even less skookum brass elbows and nipples. But it got me through the weekend.

Steel fittings will be ordered if they need to be custom made. It was a good learning experience for me though. It works for now and will be even better soon. Thanks for all the input here.
BD

 

[Tom Daly]

machine shop

I have spent lots of time mining the internet, McMaster Carr, et al hunting
a series of adapters with the desired material to get from A to B.
It turns out about $100 to a proper machine shop can get you

1 fitting, of your desired material, desired angles, desired thread types, etc. and be done with it.


-tom

 

[Brent Hodges]

How about take the M22 x 1/8 fitting and drill and tap the 1/8 hole to 1/4”?

 

[twistedtree]

The M22 side is probably straight thread? How does that seal? Is there a crush washer of some sort? I have a similar metric straight thread fitting on my engine and it takes a seal washer like one of these https://www.amazon.com/Swordfish-31...622986318&s=industrial&sr=1-10&ts_id=16410921


It might also seal the same way as an ORB hydraulic fitting where it's a straight thread with an o-ring and nut that cinches down on the o-ring to seal it. The fitting in your first picture kind of looks like such a fitting.


Anyway, sealing the M22 connection is as much a part of the puzzle as matching the threads.

 

[BDofMSP]

I used the brass parts I could find. When I assembled the port side I was about an eighth of a turn short of getting clearance for the sensor. Of course when I tried to force it, I broke the elbow.

Since then I've found an M22 to 1/4 in steel, and a 1/4 street elbow in stainless. They arrive Monday and Tuesday. Thanks for all the tips - much appreciated!