Oil pressure sender | FerrariChat

Oil pressure sender

Discussion in '206/246' started by CliffDonnon, Aug 16, 2006.

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  1. CliffDonnon

    CliffDonnon Karting

    Jan 28, 2006
    71
    My 1973 246 Dino has always had low oil pressure even with an expensive engine rebuild, had the gauge checked & is ok. I was quoted $300 & a three week wait for a new sender. Has anyone used another brand with good results?
    What should the oil pressure be hot at idle & cruising?

    Thank you.
    Cliff Donnon,
    South Australia
     
  2. John Corbani

    John Corbani Formula 3
    Honorary Owner

    May 5, 2005
    1,153
    Santa Barbara, CA
    Full Name:
    John Corbani
    Have had a Nissan sender in my Dino for about 10 years. Need an adapter to match thread sizes and have to add a resistor in series with sender. There are steps between pressure points but plenty accurate when calibrated. I picked a resistor to get a reading of 85 at 85 psi.

    I run about 90 when cold, 85 when hot at 3000. About half that at 1000 rpm idle. Pressure is up at 2000. There is a pressure regulator so things can be changed.

    Don't remember what year Nissan but early 90's. I found it in a Car Quest cross reference that had all sensors, their resistance and whether resistance went up or down. $15 sensor available right now as opposed to a $50 sensor when available. Never did order the Ferrari sensor.

    Measure the resistance of your sensor at various pressures, find the closest match and add resistor to get midrange right on.

    See what you can find. I could probably pull sensor and measure what I have but it is a hassle.

    Good luck,
    John
     
  3. dm_n_stuff

    dm_n_stuff Four Time F1 World Champ
    Lifetime Rossa Owner

    Dec 10, 2003
    43,710
    26.806311,-81.755805
    Full Name:
    Dave M.
  4. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
    4,629
    Full Name:
    Dave Helms
    Talk to Margaret at MOMA in New Mexico. She has found solutions for the AMP gauge melting and the correct sender to fix the low reading oil gauges. I worked with her on these a few years back, it was a quest of hers for sme time. Every 246 should have the AMP gauge fix of hers done before it goes into melt down. Margaret has found a 60 amp shunt that fits perfectly in place of the 40 amp that melts. Easy and cheap if she recieves a virgin gauge.

    Dave
     
  5. synchro

    synchro F1 Veteran

    Feb 14, 2005
    9,294
    CHNDLR
    Full Name:
    Scott

    This seems very interesting so I'm starting a new thread.
     
  6. synchro

    synchro F1 Veteran

    Feb 14, 2005
    9,294
    CHNDLR
    Full Name:
    Scott
  7. synchro

    synchro F1 Veteran

    Feb 14, 2005
    9,294
    CHNDLR
    Full Name:
    Scott

    Where is the Oil Pressure Sender located?
    Near the Oil filter?
     
  8. John Corbani

    John Corbani Formula 3
    Honorary Owner

    May 5, 2005
    1,153
    Santa Barbara, CA
    Full Name:
    John Corbani
    Oil pressure sender is almost under the 3-6 carburator. Stands vertically and threads into head. Easy to get at once the air box is removed. Oil temp is front center of the oil pan. Threads into front of pan. Also easy to get at once the car is on a hoist.

    John
     
  9. jselevan

    jselevan Formula 3

    Nov 2, 2003
    1,873
    I have spoken with Margaret in the past concerning the oil pressure issue. She believes that the factory installed an incorrect oil pressure sending unit in all Dinos. This sending unit, according to Margaret, does not "match" the pressure gauge. She went on to say that the Daytona sending unit is correct for the Dino.

    While this is her line of business, proper evaluation would require a hydraulic manifold and calibrated pressure gauge. I assume that she has done this. It would be a simple matter to measure pressure in the manifold with a reference (read accurate) gauge and compare against several Dino sending units and matching gauges. The sending unit is nothing more than a variable resistor, and the pressure gauge is nothing but a voltmeter calibrated for pressure.

    I should know this, but at this writing I cannot recall whether zero pressure corresponds to zero resistance or infinite resistance of the transducer (sending unit). It is easy to measure, and I shall do so tomorrow.

    In the case that zero pressure represents infinite resistance, and we all measure pressures that are inappropriately low, then adding a resistor in series will tend to accentuate the problem. One will have to add a parallel resistor in the gauge to improve the reading.

    Jim S.
     
  10. sulzeruk

    sulzeruk Karting

    Aug 8, 2006
    59
    Bonnybridge, U.K.
    Full Name:
    Alasdair Cowan
    One of the Dinos I am working on had a non functioning gauge. To see if it was the gauge or sender that was the problem, earth the connection that the sender wire plugs into and see if the gauge goes to full deflection when the ignition is on. If it does, the gauge is OK, the sender is kaput, good way of checking the wiring to it as well!
    Al Cowan
     
  11. jselevan

    jselevan Formula 3

    Nov 2, 2003
    1,873
    Al - your are correct. I checked my sending unit today and found approximately 5,000 Ohms with the engine not running. After starting, the resistance to ground decreased with increasing oil pressure. Hence, a short to ground, as you suggest, would represent infinite oil pressure (peg the gauge to the right).

    Jim S.
     
  12. synchro

    synchro F1 Veteran

    Feb 14, 2005
    9,294
    CHNDLR
    Full Name:
    Scott
    Carlo Durante changed the sender on my USA version Dino years ago, and it works great.

    Do you mean oil pressure or oil temperature?

    I believe the Oil temperature sender is mounted near the Oil filter, correct?
     
  13. John Corbani

    John Corbani Formula 3
    Honorary Owner

    May 5, 2005
    1,153
    Santa Barbara, CA
    Full Name:
    John Corbani
    Oil Pressure sensor is on top of block
    Oil Temp sensor is in front of oil pan
    Oil Pressure Idiot Light switch is by oil filter

    John
     

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