[85fsbill]

Hi gang.
I'm going to switch from the electrical oil pressure gauge and sending unit to a mechanical set up.
I work in a Mack, Volvo garage and have access to a free dual air gauge, air line and any fittings that I need.
I going the dual air gauge route because I have an onboard air system on my bronco, so one gauge needle will be for air and the other for oil pressure.
My question is What is the pipe thread size for the original elect. pressure sending unit? 1/4, 3/8 or 1/2"?
I need to know so I can have the fitting ready to go in when I pull the other out.
Just in case some of you are wondering, yes, an air gauge can be used for oil pressure. PSI is PSI weather it is oil, air or any other liquid for that matter. I've seen the setup that I'm going with in several semi trucks.
Thanks
Bill

 

[RickyB]

The new one for my '87 5.0 on my desk right now is a 3/8ths NPT----measures 5/8ths across the threads...........

 

[85fsbill]

Thanks RickyB, The size should be the same on 6 cyl. as an 8 cyl.
Bill

 

[Steve83]

I'm going to switch from the electrical oil pressure gauge and sending unit to a mechanical set up.

I advise against it. If your stock oil gauge doesn't work right, it's easy to fix.

PSI is PSI weather it is oil, air or any other liquid for that matter.

True, but a pressure diaphragm or transducer isn't a pressure diaphragm or transducer. A mechanism that works perfectly for air won't NECESSARILY be reliable or even functional with oil, ATF, or another fluid.

 

[RickyB]

I advise against it. If your stock oil gauge doesn't work right, it's easy to fix.True, but a pressure diaphragm or transducer isn't a pressure diaphragm or transducer. A mechanism that works perfectly for air won't NECESSARILY be reliable or even functional with oil, ATF, or another fluid.

Is this the old 'air compresses, liquids don't' analogy? Cuz I was questioning this myself this morning with regards to 85f's idea..........

 

[Steve83]

No, I meant something more like the old 'hot engine oil permeates & softens a rubber diaphragm that would be fine for air'. Of course, some air gauges use a flat copper reed diaphragm which would be fine for oil as long as it's rated for the pressure. But the point is: NOT ALL can be used for both oil & air, and personally; I don't want 50 psi of 210°F 20W50 shooting toward my face while I'm merging into Memphis traffic. So I'll stick with a stock gauge.

 

[SigEpBlue]

I don't want 50 psi of 210°F 20W50 shooting toward my face while I'm merging into Memphis traffic. So I'll stick with a stock gauge.

Pffft. Fat lotta fun YOU are! :goodfinge


[on a related note]
I dunno if you remember, but a while ago, I wanted to try and use an electric oil pressure gauge and sending unit on the fuel rail, so I could monitor pressure at WOT and higher engine speed. I decided against it due to the fact that if the sending unit leaks, it'd be spraying or leaking gasoline all over a hot engine. It's even worse now since my EGR valve is almost right next to the fitting. :toothless
[/on a related note]

 

[Steve83]

:topic
Steve
Are you receiving my e-mails? I re-sent the one about the air filter box bracket. E-mail me about it one way or the other.

 

[SigEpBlue]

Payment sent. Also, sorry it took me so long.

 

[85fsbill]

Steve83, point well taken. But I have seen at least 2 older Macks that had the setup I was going to use. The older Macks had 60 to 90 psi oil pressure.
You have put second thoughts in my head, maybe I'll just buy a mechanical oil pressure gauge.
Knowing how many people you have helped with your knolage and wisdom, one would be a fool to dought you. I'm not saying that sarcasticly, you are the man with the answers. You've solved a few of my problems.
Bill