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Flathead Ford oil pressure

Discussion in 'The Hokey Ass Message Board' started by JAFA, Oct 3, 2009.

  1. JAFA
    Joined: Mar 26, 2008
    Posts: 5

    JAFA
    Member

    I have a 51 ford with a 51 Merc flathead in it with 61,000 miles running straight 40 weight oil. The oil pressure after warming up is 2lbs at idle and 12 running. I have been told that this isn't uncommon. It just seems low to me.

    What kinda of oil pressure are most flatheads run?

    Also if this is uncommon what do you recommend to fix this problems? I was looking at the Melling M-15 high pressure pump. But I have read that it doesn't increase the pressure in a stock.

    Thanks for any help
     
  2. RDAH
    Joined: Mar 23, 2007
    Posts: 465

    RDAH
    Member
    from NL, WI

    I run 20w50 oil in both of mine and at start up I have 50 lbs. after warm up 30 and at idle 10. Put a can of STP in your flathead and you should gain 8 to 10 lbs of presure.
     
  3. j ripper
    Joined: Aug 2, 2006
    Posts: 710

    j ripper
    Member
    from napa ca.

    just take care of it and drive it..
     
  4. BLUDICE
    Joined: Jun 23, 2006
    Posts: 980

    BLUDICE
    Member

    My '50 starts at +40# at idle, cruise @ 60#, idles warm @ 30# thats on the dash gauge - my friends say thats great. One friend has a '49 Merc and it runs at -30# and he says flat heads are that way - keep oil in them and just drive it!
     
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  5. havi
    Joined: Dec 30, 2008
    Posts: 1,869

    havi
    ALLIANCE MEMBER

    they are pretty forgiving, unlike new tight clearance engines.
     
  6. Before getting TOO alarmed, try hooking up a REAL gauge to the pressure tap on the back of the engine.
     
  7. srosa707
    Joined: Jun 5, 2005
    Posts: 1,551

    srosa707
    Member
    from Sacramento

    Mine starts at 65, 20-25 when warm, 10 at idle, and 0 after about 15 minutes on the highway. I look like the old video game where you can shoot an oil slick out the back of your car.
     
  8. j ripper
    Joined: Aug 2, 2006
    Posts: 710

    j ripper
    Member
    from napa ca.

    Would that be Spy Hunter?
     
  9. srosa707
    Joined: Jun 5, 2005
    Posts: 1,551

    srosa707
    Member
    from Sacramento

    I was trying to think of that damn game! Thanks J RIPPER
     
  10. Diavolo
    Joined: Apr 1, 2009
    Posts: 758

    Diavolo
    Member

    I agree with getting a gauge and tap the fitting on the oil filter canister. The readings I get on my 52 are just about 30 warmed up, running 40wt. It is not uncommon for very low oil pressures, though.
     
  11. 51 MERC-CT
    Joined: Apr 5, 2005
    Posts: 1,579

    51 MERC-CT
    Member

    As stated previosly, install a mechanical gage ( if you are using the original electric) to give a more accurate idea of what oil pressure really is. Read somewhere once that 5lb. oil pressure for every 1000 RPM is adequate.:)
     
  12. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,301

    Flat Ernie
    Tech Editor

    Agree with all posted so far (confirm with good mech gauge, not uncommon). You can try running some 50wt or 20/50, but it probably won't make much difference.
     
  13. R Pope
    Joined: Jan 23, 2006
    Posts: 2,985

    R Pope
    Member

    I've seen flatties run for years that wouldn't even wiggle the gauge when they got warmed up. Any flow at all seems to be enough as long as you don't really get on it a lot. Most of the engines I'm talking about were in grain trucks, though, and they don't get treated gently.
     
  14. jetmek
    Joined: Jan 12, 2006
    Posts: 1,844

    jetmek
    Member

    your engine should run 50-60 lbs at speed. sounds like bottom end is worn out. if its not knockin just treat it gently and it should last a while....
     
  15. 296 V8
    Joined: Sep 17, 2003
    Posts: 4,682

    296 V8
    BANNED
    from Nor~Cal

    Like most have said that’s about normal and not uncommon.
    On a 40 convertible I had to keep running it had low presure like that plus it would burn a qt. every 300 or so miles.
    I barrowed some 70wt from the boss’s top fuel trailer before a trip to billet proof (200 + mil) and only burned a pint.
    If your real worried, clean the pickup and put in a fresh pump.
     
  16. JAFA
    Joined: Mar 26, 2008
    Posts: 5

    JAFA
    Member

    Thanks for the help. I'm just going to leave it alone and drive it.
     
  17. gaspumpchas
    Joined: Apr 5, 2007
    Posts: 176

    gaspumpchas
    Member

    Try using 15w40 Diesel grade oil, this stuff's like liquid ball bearings!! Do you have any thumping at idle??? Good luck

    gaspumpchas

    "Ah, s*it, it's Holstein..............."
     
  18. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,301

    Flat Ernie
    Tech Editor

    I also noticed a slight increase in my hot idle oil pressure when I switched to Diesel too. I think it's the additive packages they use.
     
  19. T Weed
    Joined: Dec 5, 2004
    Posts: 97

    T Weed

    I gotta 59ab in my T roadster and it has about 3 lbs when warm idling. When i first got it running I asked my buddy who has been around since 1940 and built every kinda motor imaginable if i should be worried. He asked me how much pressure I had when warm, and I told him about 3lbs, he says "thats enough". Well, thats 3 years ago and shes still going strong. I run 20w50 and a can of STP...hope that helps, Weed
     

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