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SBC radiator overflow expansion tank

Discussion in 'The Hokey Ass Message Board' started by Pro Stock John, Oct 16, 2011.

  1. I searched around, but if there is a good thread let me know and I'll just read that one....

    350 SBC, supposedly crate, no idea on power
    Big cam
    12 psi rad cap
    E Fan

    Runs great, cools great. I need an overflow can if I want to make some passes at the track. I'd like something that will suck the coolant back into the radiator. If I fill it to just under the cap hole it might puke some out, if I fill and just cover the fins I don't think any comes out.

    Would this do the trick?,7302.html?parentDisplayId=7303


    I don't understand how the vent line would work here, I wouldn't want it to vent from the button..?

    To recap I like the idea of having an extra 6-10 ounces of coolant, then it would be one less thing to check every other time I drive Mercula.

    Right now I just have a dangling rubber hose.

    I know what a coolant catch can is I'm not looking to just run that.
  2. Cerberus
    Joined: May 24, 2010
    Posts: 1,390


    I've run the Speedway SS one on several cars with no issues. They come in different diameters and lengths depending on space restrictions. Never been a fan of the plastic ones, even though I had one on a '55 wgn for 12 years, worked perfectly accept for being ugly.
  3. EnragedHawk
    Joined: Jun 17, 2009
    Posts: 1,113

    from Waco, TX

    I would actually like to know myself. I've been searching the forum as well but couldn't find anything useful. I know overflow tanks have two lines, but where do they both connect to? I know where the puke line runs, but I don't understand how the return line works. Any help here would be awesome.
  4. I took one of the $20.00 plastic tanks, pulled out the fitting and the grommet on the top, stuck a hose (rubber fuel line) on the end of the fitting that goes into the tank and reinstalled the fitting onto the tank. The diameter of the rubber fuel line hose will keep the assembly in the tank.

  5. 39 Ford
    Joined: Jan 22, 2006
    Posts: 1,558

    39 Ford

    The overflows are not HAMB traditional, I have one on my car!
  6. dorf
    Joined: Dec 5, 2008
    Posts: 1,087

    from ohio

    the line comes in the bottem of the catch can,when the fluid expands in the radiator it pushes the fliud out into the overflow when it cools it leaves space in the radiator and the fliud runs out of the overflow bottle and back into the radiator. the second line is for the overflowing of the catch can and is just a drain
  7. squirrel
    Joined: Sep 23, 2004
    Posts: 50,274


    If you want the coolant to get sucked back into the radiator, make sure the radiator cap has the rubber gasket around the outside, to seal the outer part of the radiator neck. Most modern caps do, but some just have a metal surface, not rubber.

    As long as the overflow tube reaches the bottom of the puke can, it will be able to suck the coolant back into the radiator as it cools.
  8. EnragedHawk
    Joined: Jun 17, 2009
    Posts: 1,113

    from Waco, TX

    Awesome. That takes care of what I needed to know. Thanks!
  9. Just like a modern car the hose enters the top and extends to near the bottom of the tank. In the case of these $20.00 plastic tanks the bottom has a petcock for draining.

    Attached Files:

  10. sedanbob
    Joined: Apr 19, 2011
    Posts: 110


    Coolant recovery tanks usually have two lines - one feeds into the bottom of the tank - that's the one you hook your line to from the radiator. The other line extends up into the tank, ending just below the top. That is the overflow for the recovery tank. Any coolant over the top of that tube, will drain out the bottom - most put a short hose on that fitting to direct any overflow closer to the ground so it doesn't dribble over your engine compartment.
    You want a tank that will hold a little more than what currently dribbles out the radiator overflow when your radiator was full to the top. Measure what you have to put back in to top it off, add a couple of ounces, and that capacity should work for you. Hope this helps.
  11. 32Rules
    Joined: Mar 17, 2007
    Posts: 203


    Here is a hamb friendly solution on my 32

    66corvette expansion tank
  12. 57tailgater
    Joined: Nov 22, 2008
    Posts: 745

    from Georgia

    If you notice on newer cars, they usually have a reservoir that has a pressurized cap and is not on the radiator itself. This is where the pressure and coolant expansion is contained within the coolant system as the coolant heats up and expands. On an older system, you will see usually the puke tube is on the outside of the radiator cap sealing surface. The cap opens up as things heat up and pressure builds up past its rating. When there gets too much pressure from too much heat, it opens outward (from the radiator) and allows pressure to be relieved and coolant to dump out. I do not think there will be too much coolant sucked back into the system prior to the cap closing back up. Overflow tanks are just that - for overflow and collects what gets puked out. I believe the drag rules intent are to make sure any coolant doesn't get spilled out onto the track therefore you will need a large enough tank with a manual drain to contain what you may overflow. If you really want a "surge" tank (which we call it in my work world) you will need to have a tank than can be pressurized which means the tube from the radiator needs to be on the inside/pressure side of the cap seal and your pick up tube going to the bottom of the tank. This would allow the coolant to expand over into the tank then get sucked back into the main cooling loop as it contracts. This is normal within the operating parameters of any engine. The cap is the pressure relief/safety valve should anything exceed what it should be and prevent damage to components. The trick is to have a cooling system that keeps things in check. I hope this helps. :cool:
  13. My first issue is to not have any coolant leak to the ground, and a bonus would have a setup that would drain back into the radiator.
  14. I usually end up using a small gas can (like say 1/2 to 1 gallon). just make your hose lay in the bottom of the can so it can pick up when your radiator cools and draws it back in. I never put more coolant in the can than just covers the hose it is not a coolant reservoir it is an overflow.
    Last edited: Oct 17, 2011
  15. MRTS33
    Joined: Aug 17, 2011
    Posts: 207


  16. stubbsrodandcustom
    Joined: Dec 28, 2010
    Posts: 1,545

    from Spring tx

    mine is a lonestar beer bottle with a copper tube wrapping around it and then drops inside the bottle 1/2 inch from the bottom of the bottle... works fine... :D you guys running polished alum tanks etc are lacking creativity...
  17. Thanks guys. I don't like billet stuff whatsover, I could do black plastic too. I want something that can recirculate coolant only because that adds another bit of reliability to the car which has been my primary focus all summer.
  18. Don't forget to replace the radiator cap with a "closed system" radiator cap.

    I forgot to mention it before but I believe someone else did.
  19. Delsiii
    Joined: Apr 22, 2007
    Posts: 7


    Thats called a still ;)

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