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How many lb radiator cap can I run?

Discussion in 'The Hokey Ass Message Board' started by Tindall, May 5, 2010.

  1. Tindall
    Joined: Jun 7, 2007
    Posts: 399

    Tindall

    i have a 409 with a 32 radiator made by us radiator. I have a 13 lb cap on now and when i shut the engine off i shoots out a 1/4 gallon..

    [​IMG]
     
  2. cartcoupe36
    Joined: Mar 16, 2009
    Posts: 39

    cartcoupe36
    Member
    from Acworth GA

    i've got a 22lbs cap on a 36 ford works great, had the same problem with mine too
     
  3. 61TBird
    Joined: Mar 16, 2008
    Posts: 2,640

    61TBird
    Member

    Try a 6 or 7lb cap.
    The 390 in my Tbird loved to puke out it's Coolant until I replaced the 13lb with a 7lb cap.
     
  4. 61TBird
    Joined: Mar 16, 2008
    Posts: 2,640

    61TBird
    Member

    That's called "Spam".
    In the lower left corner (below the username) there is a "report" button.
    Click on that and type "Spam" in the window that opens up.
     

  5. brad chevy
    Joined: Nov 22, 2009
    Posts: 2,627

    brad chevy
    Member

    Damn this dude,or whatever it is has made 7 posts and there all stupid as hell.just go get on the show America don"t have talent.
     
  6. Tindall
    Joined: Jun 7, 2007
    Posts: 399

    Tindall

    so how many lbs can an engine/rad. handle...ive had a 7 on there and it was worse...its been better with the 13
     
  7. Model A Vette
    Joined: Mar 8, 2002
    Posts: 1,075

    Model A Vette
    Member

    Matt-Are you running an overflow catch can? The catch can will catch the overflow and when the engine cools it will suck the fluid back in.

    Another question: Do you have the radiator braced to the top of the engine? That's not a good idea. The engine torque will twist the radiator.
     
  8. Hoptup Jalop
    Joined: Sep 29, 2004
    Posts: 1,118

    Hoptup Jalop
    Member

    latest (June) copy of Street Rodder has a great section on cooling...call us radiator and ask them what they recomend....5-15 should be sufficient though.
     
  9. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    tommy
    Member Emeritus

    You can build a coolant recovery tank out of a lot of things. Run the over flow tube down to near the bottom of the tank so that it remains under the fluid level in the tank. When the engine cools the coolant contracts forming a vacuum sucking the coolant back into the radiator out of the recovery tank just like a modern car. You can get them for streetrods or make one that looks more traditional.
     
  10. No offense but why don't you put a puke can on it with a dip tube then it will work like any other pressurized system. You shut it down it pukes and when it cools off it drinks it all back up.

    I normally run a 13 lb cap on about anything I have. A catch can and the only time I ever really have a problem is when I hit a large bird and it make a hole in the rad or if by some freak of the imagination my T stat sticks.
     
  11. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,257

    Ebbsspeed
    ALLIANCE MEMBER

    This is going the wrong direction, a 7 lb cap will puke before a 13 lb one will.

    Are you refilling the radiator after each puke? If you are, this may be your problem. Back in the days before catch cans/overflow tanks the cooling systems were designed to have a bit of air at the top of the radiator. This air "bubble" would compress as the system heated up, and at operating temperature would keep the coolant level low enough to not blow out the overflow tube. On these systems you would fill to a level an inch of so below the cap, then run the engine through a few heat/cool cycles. It would puke a couple of times, and the system would normalize to a level that worked. And as long as it still cooled you were fine. But Carla Cat Lover and Danny Dog Doer didn't like their pets slurping up the ethylene glycol overflow from the streets and dying a slow, painful death from kidney failure, so another method was adopted. The coolant recovery system, which consists of a different type of radiator cap and an overflow tank. This type of system uses a tank to store the overflow, and basically removes that air bubble from the radiator. A check valve and spring loaded pressure release valve built into the radiator cap control the flow back and forth from the radiator to the overflow tank.
     
    Last edited: May 6, 2010
  12. gas pumper
    Joined: Aug 13, 2007
    Posts: 2,957

    gas pumper
    Member

    The best solution is what Tommy and Porknbeaner have said.

    Without a place for the expansion to go, it's gonna puke.
    But after it pukes that's the level it will be happy at and should not puke more. With a non recovery tank system you need to run the water level low enough that the expansion volume can be contained in the radiator tank. This is one reason why old systems had large header tanks. Another reason for large tanks was a larger amount of water in the engine and radiator=more fluid to expand.

    You could just leave the level down where it likes to be. The only downside I've seen with this is a little less cooling efficiency, the engine will run a little hotter when it's really hot outside. I think due to air bubbles churning in the water.
     
  13. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    tommy
    Member Emeritus

    [​IMG]

    Stolen from the Mitchel Muffler post.

    Notice the WWII canteen on the firewall. It's now a coolant recovery tank. Instead of puking on the ground the fluid rises in the tank and falla back down when it gets sucked back into the radiator. Some amazing details on this ride.
     
  14. Doc.
    Joined: Jul 16, 2005
    Posts: 3,558

    Doc.
    Member Emeritus


    Tommy, what's the scoop on the generator for?

    Doc.
     
  15. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,257

    Ebbsspeed
    ALLIANCE MEMBER

    The scoop is an air intake, and FYI, that's not a generator, it's a small gas turbine to add a little more power to the flatty. :D
     
  16. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    tommy
    Member Emeritus

    It's only a guess but it might be military also. There is no pulley fan to move air and no slots at the rear. It might have been an explosion proof model that had cooling air piped in from outside. The scoop would gather air from the engine fan. It's just a guess but that is what comes to my mind. I've never seen one before.
     
  17. He is smart. You are filling it too full and need a recovery tank.
     

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