Oil line for gauge

[rob love]

Absolutely, but since the supply of oil will be more than required for the line and to do the little amount of work required within the gauge, it will compress the trapped air to an equal pressure, which will be read by the gauge. . There may be a slight to negligible delay in the reading of the gauge as the air compresses or decompresses, but it will be too slight to notice.

[rob love]

Here is a link to the same discussion over on the HAMB: https://www.jalopyjournal.com/forum/...e-gauge.31196/


One fellow mentions something that I was thinking about re air in the line: It can act as a shock absorber if there is pulsing of the supply. Now that is not really a big problem on the engine oil pressure system, but I do run into it on well pumps and in some hydraulic and fuel systems. There are dampers/accumulators that can be installed to counter this.

[Richard Farrant]

Originally Posted by rob love

Absolutely, but since the supply of oil will be more than required for the line and to do the little amount of work required within the gauge, it will compress the trapped air to an equal pressure, which will be read by the gauge. . There may be a slight to negligible delay in the reading of the gauge as the air compresses or decompresses, but it will be too slight to notice.

Rob,
I have to disagree on your last sentence, referring to one particular vehicle, (Daimler Dingo). If you have been working on it and go to start up and nothing showing on the gauge, alarm bells ring. I can tell you that it is much more of a delay than you describe, possibly due to the length of pipe. There is a difference between theory and practice. Having had 52 years on engines you don't take chances!

[rob love]

Richard


In the case of the Dingo, or any other similar transmission of a signal over a long length of tube, I'll agree. But in the case of the usual 2 foot length of tubing as used on normal vehicles, It is not a great consideration.



I had an interesting experience with the plastic tubing for an oil gauge which I would like to relate. It was on a M38 Jeep that had been converted to 12 volt. I was driving it when suddenly I had a bunch of smoke and the oil gauge reading zero. I immediately shut off the vehicle and opened the hood. The oil line had somehow contacted with the exhaust manifold and melted open. It then melted shut. I was able to continue on my way. I'll never use the plastic stuff again.

[Richard Farrant]

Originally Posted by rob love

Richard


In the case of the Dingo, or any other similar transmission of a signal over a long length of tube, I'll agree. But in the case of the usual 2 foot length of tubing as used on normal vehicles, It is not a great consideration.



I had an interesting experience with the plastic tubing for an oil gauge which I would like to relate. It was on a M38 Jeep that had been converted to 12 volt. I was driving it when suddenly I had a bunch of smoke and the oil gauge reading zero. I immediately shut off the vehicle and opened the hood. The oil line had somehow contacted with the exhaust manifold and melted open. It then melted shut. I was able to continue on my way. I'll never use the plastic stuff again.

You were lucky with the M38 incident!
Most of the armoured vehicles of days gone by, had engines in the rear with several Yards of pipe ( Metres to you guys ). Nowadays it is all done by electrickery sensors.

[Lynn Eades]

I'm with you Rob. Many gauges come with a very fine capilliary tube. Some are long. There is no way to bleed the air out of them. The gauge is usually mounted higher than the other end and is not designed to be bled of air. Thick cold oil in the tube would have friction and be slow to move. However air would be instantaneous.

[Richard Farrant]

Originally Posted by Lynn Eades

I'm with you Rob. Many gauges come with a very fine capilliary tube. Some are long. There is no way to bleed the air out of them. The gauge is usually mounted higher than the other end and is not designed to be bled of air. Thick cold oil in the tube would have friction and be slow to move. However air would be instantaneous.

Lynn,
We are not talking sealed capilliary gauges, the ones I were referring to have a pipe nut connection at the gauge, you slacken the nut off and run the engine until oil appears, nip up the nut and it is all sorted.

[Lynn Eades]

Richard, My point is:
If you don't have to bleed the ones with a fixed capillary tube, and they work ok with a head of air trapped in them, then why would you need to bleed the others?

[Jordan Baker]

Great discussion and all but any pictures showing the route of this line?

[Lynn Eades]

Sorry Jordan.

[Bruce Parker (RIP)]

Originally Posted by Jordan Baker

Great discussion and all but any pictures showing the route of this line?

Sorry Jordan.


Two options: take lots of pics as you dis-assemble or buy another wreck that is crappy but original as a reference (and maybe a future restoration).

Or run it where it make sense and replace it when you get better information (and pat yourself on the back if you got it right). The Chev manual unlike Ford is particularly unhelpful.