Pre He Oil Pressure Sensor


(v12jag cobra) #1

Hi all
I have a pre he 5.3 V12 engine fitted in my Dax cobra kit car and want to check the oil pressure gauge
the oil pressure sensor is new and of the variable resistance type and the gauge is standard Jaguar Smiths. I need to Know the resistance of the oil pressure sensor at pressures between 0 and 80 psi so I can calibrate the gauge utilising a variable resistor and ohm meter.
Does any member have this information
Thank you
Peter


(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #2

You do realize it doesn’t make much difference, right? As long as the guage indicates pressure it will serve its purpose.


(v12jag cobra) #3

Hi Kirbert,

I just want to make sure the gauge is indicating the correct oil pressure accurately. I may be being a bit fussy but my background is instrument engineering. I could take the pressure sensor off and do a system calibration using a calibration pump and digital pressure gauge, but the sensor is rather difficult to access in my car.
Peter


(Aristides Balanos) #4

Are the Pre HE sensors different from the HE ?
And the 6 from the 12 ?
Isn’t your gauge matching ?

I have a 6 cylinder Oil Pressure gauge in my drawer, I could measure it’s Pressure reading vs Resistance and that would essentially give you ths sender’s characteristics.

Aristides


(v12jag cobra) #5

Hi Aristides
Thanks for the reply, Why didn’t I think of that as I have a standard gauge which is matched to the pressure sensor.
Thanks Peter


(PeterCrespin) #6

Check if your Cobra gauge/sensor pIr xesjgbed for 12V or regulated 10V from a small instrument panel bi-metallic voltage regulator. Most ar 12V…


(Mark Eaton) #7

Hi Peter,

Just watch out for a mismatch. Some of the early senders were bimetallic and switched to 10V and ground. The 10V was supplied via another regulator behind the instrument panel. Those matching gauges were interested in the average current. They were actually very elegant and responded smoothly due to the thermal time constants involved.

If you have a variable resistance sensor, mated to the wrong gauge, then may not work at all accurately. According to the MG forum, they expect 110mA for 100PSI and 84mA for 50PSI and 20mA for 0PSI. Logarithmic.

But this has been recorded elsewhere in the Jag archives:


SENDER:- “PTR1001/10ec 700kN/m(squared)”

Pressure(psi), Resistance(Ohms) : 0 290 , 10 264 , 20 226 , 30 188 , 40 154 , 50 122 , 60 95 , 70 76 , 80 55 , 90 37 , 100 20

GAUGE:- ACP2203/00 (100psi)

  • “B” to “T” = 240ohms
  • “T” to “0V” = 326ohms

Don’t know if that helps or confuses !


(Mark Eaton) #8

Also, refer to this previous post:

https://forums.jag-lovers.com/t/e-type-here-is-a-procedure-to-calibrate-your-oil-pressure-gauge/89434