Oil Pressure on 16-2

[rleonard]

I am working on my origional CS 16-2.  There is a plug at the top of the oil pump where the old Lister books show a pressure gauge installed but do not indicate the range.  I'd like to re-install a gauge.  Those of you that have done so, what pressure are you seeing? 

Bob

[EVguru]

You should have a tap fitted between the pressure take-off and the pressure gauge and only open it long enough to check there is oil pressure (the pulses would eventually dammage the gauge).

No pressure range is indicated in the manual, although RocketBoy says on his site that he normally saw 35 psi (10 psi with a broken pump spring).

[rleonard]

I have the plug there but no gauge (yet).  I think a nice brass gauge would look nice as well as give important information.  At Steve's Old Engine Shed, He has one installed on his.

http://www.oldengineshed.com/graphics/listgen13.jpg

Either a valve or utilizing a glycerine filled gauge would address the pulsation problem.  Good point EV.  I have several gauges a home.  Will experiment when I get back up and running.  Everything is apart now working on the base and generator mounting.

Bob

[Tom]

Seems like a small orifice opening to the gauge would resolve the pulsing issue and make it easier to read the pressure too.

[Halfnuts]

Hi Tom,

Seems so, but that won't work unless there's something compressible in the line.  The principle that's involved is called Pascal's Principle (the man was a true genius) and is the basis for how hydraulics works.  When you place an incompressible fluid like oil in a closed container and exert some pressure on the fluid, the pressure is distributed evenlly throughout the fluid, even to the end of a long, thin tube.  So the pulses from the oil pump would be telegraphed through the oil line hammering the gauge to pieces.

However, place a large enough bubble of air on top (say a 2" length of 1/4" steel pipe) of the oil and the air will compress like a spring, evening out the pulses somewhat.  Restrict the air by placing a small orifice, such as a barely cracked open valve, beneath the gauge and you should be home. 

Plumbers often install an upturned section of pipe in homes to minimize "water hammer."  The trapped air in the upturned pipe absorbs the pressure pulses caused by turning valves on and off.

Be sure to use steel fittings and pipe throughout because brass will fatigue and eventually snap off from the vibration.

Halfnuts

[GuyFawkes]

There is a comment that needs to me made here.

Pumps have two characteristics, pressure and flow.

I don't know how many pumps I have seen producing pressure which was indicated correctly on a gauge, and yet the motor wasn't oiling right because the flow wasn't sufficient, or in some cases wasn't uniform throughout the engine.

re putting an accumulator (for that is what they are called) in the line to even out the pressure for the benefit of the gauge, it will ALTER the pump characteristics, esp if the gas volume in the accumulator section is an appreciable proportion of the pump stroke displacement, and this can dramatically alter how the pump delivers lube, both actual volume flow and pressure through the bearings.

if you have to fit a gauge, use an ball valve, and test it for a second or two, that is if you have to fit a gauge.....

[MikeyT]

I posted a (crappy) photo of a 12/2 w/ a guage to Coppermine, looks to to be 0-10 PSI.

[dkwflight]

Here is a pic of my Power Solutions oil pump.
http://s29.photobucket.com/albums/c294/dkwflight/?action=view&current=100_0136.jpg
Dennis

[rleonard]

DKW,
When you open the valve with the engine running, what pressure does it indicate?

Bob

[dkwflight]

Hi the needle is a blur , about 15 psi peak. The gage is not too good
Dennis

[rleonard]

Thank you Dennis.

Bob