Oil pressure gage psi range

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gary koehler
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Oil pressure gage psi range

#1 Post by gary koehler » Fri Jun 16, 2017 7:33 pm

I just installed a 904 style gage from PA Speedo in my '62; it has a healthy 912 motor in it. Just noticed that the max pressure is 70 psi!! Senior moment I guess, and I need to change its range. Seeking advice on what the maximum and mid-range pressures should be for a large pump motor. Thanks for all advice,
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David Jones
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Re: Oil pressure gage psi range

#2 Post by David Jones » Fri Jun 16, 2017 8:44 pm

Depends on the oil pressure relief valve spring but cold oil pressures with a heavy oil could easily exceed 60 psi if the engine were revved with cold oil.
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Doug McDonnell
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Re: Oil pressure gage psi range

#3 Post by Doug McDonnell » Fri Jun 16, 2017 8:49 pm

Most PSI gauges are 0-70 and the BAR ones are 0-5 BAR . 5 BAR is 72.5189 PSI You should be fine. viewtopic.php?f=1&t=9432&hilit=maximum+oil+pressure
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Ron LaDow
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Re: Oil pressure gage psi range

#4 Post by Ron LaDow » Fri Jun 16, 2017 9:03 pm

Gary,
The pressure at that point (after the relief valve) is supposed to peak at something like 46PSI. If you need a gauge with a higher reading, someone figured they knew more about oil pressure than the factory.
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Vic Skirmants
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Re: Oil pressure gage psi range

#5 Post by Vic Skirmants » Fri Jun 16, 2017 10:11 pm

46 PSI?Where did that number come from?

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Ron LaDow
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Re: Oil pressure gage psi range

#6 Post by Ron LaDow » Fri Jun 16, 2017 10:30 pm

Vic Skirmants wrote:46 PSI?Where did that number come from?
Spec book, pg 25:
"27. Oil Pressure, warm engine at 2,500RPM, 3.0 bar."
Is there a spec otherwise?
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Al Cole
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Re: Oil pressure gage psi range

#7 Post by Al Cole » Fri Jun 16, 2017 11:22 pm

3.0 Bar equals 43.5 PSI
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Ron LaDow
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Re: Oil pressure gage psi range

#8 Post by Ron LaDow » Sat Jun 17, 2017 12:08 am

Al Cole wrote:3.0 Bar equals 43.5 PSI
Al, when Vic asked, I looked at what was on the desk. I recall the equivalent of "46.8 PSIG" in another shop reference back there in the hall.
Regardless, a 70PSI gauge is gonna be fine.
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Neil M. Fennessey
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Re: Oil pressure gage psi range

#9 Post by Neil M. Fennessey » Sun Jun 18, 2017 6:44 am

Atmospheric pressure at sea level at standard conditions = 14.7 psi = 1 atm = 1 bar

At 5 bar, the sender resistance should be about 180 ohms. At 0 bar = 0 psi, the resistance is 10 ohms.
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neilbardsley
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Re: Oil pressure gage psi range

#10 Post by neilbardsley » Mon Jun 19, 2017 11:29 am

I regularly have about 65/70 psi on my aftermarket gauge when I rev the engine. It idles about 35/40. I believe the gauge was calibrated by the previous owner before installing.

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