Oil pressure

Discussion in 'Race 400/430/455' started by slimfromnz, May 23, 2015.

  1. slimfromnz

    slimfromnz Kiwi Abroad

    Ok guys,
    I always start my engine with oil pressure. I can disable the ignition with the flick of a switch and that's how I prime the engine for oil pressure when it's cold.
    Problem is, it takes a good 20sec of cranking to gauge any pressure. If I try and start it with the ignition on, oil pressure builds pretty quick.
    Am I too conservative?
    Cheers
     
  2. DaWildcat

    DaWildcat Platinum Level Contributor

    Interesting question, looking forward to seeing the feedback. For what it's worth, at 160 cranking rpm and 20 seconds with ignition disabled, you're looking at about 53 revolutions with zero cylinder pressure before the gauge comes up. Assuming immediate startup with ignition enabled and the engine at 1300 rpm for two seconds before gauge pressure, you're looking at about 43 revolutions (plus whatever cranking required before ignition), but there's some cylinder pressure (thus a little more bearing pressures) involved before you're seeing gauge pressure in that scenario.

    Devon
     
  3. slimfromnz

    slimfromnz Kiwi Abroad

    I understand what you are saying Devon.
    Can't comment on the time it takes to gain oil pressure when cold with ignition on. Maybe there is something in the weight of oil I run, 20W50.
    Remembering this is an alloy TA block and pressure transducer is at the rear oil manifold.
    Cheers
     
  4. buicksstage1

    buicksstage1 Well-Known Member

    Try bleeding of any air that might be trapped in the line. Crack it open at the back of the gauge and let it drip into a can until you are sure it is free of air and see if that changes things.
     
  5. TORQUED455

    TORQUED455 Well-Known Member

    Accusump! :TU:
     
  6. Jim Rodgers

    Jim Rodgers Well-Known Member

    Yes you are. The quicker you get it cranked and running the better.
     
  7. gsx678

    gsx678 Well-Known Member

    I crank mine for about 5 to 10 seconds before I pump the gas and my oil pressure come right up.
    If I don not do the"pre-start" crank it takes about 5 seconds to get pressure on the gauge.
    I have not tried to bleed the gauge line.
     
  8. TheSilverBuick

    TheSilverBuick In the Middle of No Where

    x2. Soonest it's running the better. If concerned the oil is too thick, change the oil.

    And if I'm reading it right, there is no oil line to the gauge, it sounds like it's an electric gauge. I did note about a 3 second difference in time lag between the electric gauge reading and the mechanical one when I had both plumbed into a tee on my Firebird's engine.
     
  9. slimfromnz

    slimfromnz Kiwi Abroad

    Sorry guys, it is an electric sender and gauge.
    Sounds like I am reading too much into it. I should just fire it up straight away.
    Taking a friend out this morning for a bit of a cobweb blowout :3gears::shock:
    Cheers
     
  10. hugger

    hugger Well-Known Member

    This is on my list as well
     
  11. TheSilverBuick

    TheSilverBuick In the Middle of No Where

    I think it's Moroso(sp?) that makes a remote oil filter adapter that has a built in oil pump with an external hex drive that you can use a drill with a socket on it to spin the pump to pressure up the system if it has sat for a while. A friend of mine has it on his car that doesn't get started up very regularly (and also makes a smidge over 1,000HP N/A!)
     
  12. DaWildcat

    DaWildcat Platinum Level Contributor

    Royden,

    You mentioned this as a "cold" procedure. Out of curiosity, after a warm run and shutdown, have you ever repeated your same "cold" procedure and had the same apparent delay in gauging oil pressure? If not, I'd be interested in knowing what what you see if you try the same within a minute or two after shutdown, versus 15 minutes. In both cases, the oil will still be plenty warm.

    You can see where I'm going with this; if you're losing prime, 15 mins should be plenty of time for it to happen, but in both cases I'd think you'd see pressure more quickly because of lower viscosity due to higher oil temperature.

    And forgive me, I don't remember the details about your oiling system.

    Devon
     
  13. Steve Reynolds

    Steve Reynolds SRE Inc

    Not sure if Moroso makes one , but I know Peterson Fluid Systems does.

    And by the way, I always pre-lube using my MasterLube. Best investment for a Buick 455 race engine! It also maintains oil pressure through the taps while hard on the brakes. (I know because when I forget to turn it on the oil pressure will drop and fluctuate slightly. When the engine starts turning over I'm at 50-60 PSI on the gauge. Cant beat that! I also plug in my oil heater for about an hour before firing up for the first time of the day.

    Steve
     
  14. Thumper (aka greatscat)

    Thumper (aka greatscat) Well-Known Member

    Agreed.
     
  15. BQUICK

    BQUICK Gold Level Contributor

    The only way cranking to build oil pressure would make any sense would be if you pulled the plugs and had no load on the bearings. Otherwise all you are doing is hindering the pump from priming quickly and causing wear.
     
  16. slimfromnz

    slimfromnz Kiwi Abroad

    Its something we always did with the race car, just dont remember it taking so long. It was 20yrs ago though
    Cheers
     
  17. Bluzilla

    Bluzilla a.k.a. "THE DOCTOR"

    Accusump & Oil Heater here also.:Brow:
     
  18. stagetwo65

    stagetwo65 Wheelie King

    I second everything Steve said, from the oil heater on down. I use my MasterLube as a pre-luber prior to starting and also it eliminates that loss of oil pressure down in the shut down area. Mine was bouncing off of zero prior to installing the MasterLube, now it never drops below 20 psi. :TU:
     
  19. buicfrank

    buicfrank Well-Known Member

    Does the Masterlube come with all the attachments and connections? Frank
     
  20. stagetwo65

    stagetwo65 Wheelie King

    yes, it comes complete with everything you need!
     

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