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Technical How To Improve Cooling

Discussion in 'Traditional Hot Rods' started by Ehlien, Sep 28, 2016.

  1. David Gersic
    Joined: Feb 15, 2015
    Posts: 1,796

    David Gersic
    Member
    from DeKalb, IL

    I have one like this:

    [​IMG]

    http://www.speedwaymotors.com/Tech/Transmission-Coolers

    mounted under the radiator on my 37 Chevy. Seems to work ok, trans doesn't seem to overheat, though it's a 700R4 and there isn't currently a lockup for the torque converter, which is costing me some efficiency and creating some heat, so that's on my list of things that need fixing.



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  2. David Gersic
    Joined: Feb 15, 2015
    Posts: 1,796

    David Gersic
    Member
    from DeKalb, IL

    210 should be fine. 220 even. As long as it's not boiling over, you're fine. The boiling point is determined by the mix you're running and the pressure you're running it at.

    180 or 190 would be ok, for water in an unpressurized system. That applies to some cars here, but not what you're building.

    I have this gauge in my 37 Chevy ('74 350 SBC):

    [​IMG]

    From cold startup it warms up to what looks like about 240, then drops to 210 and stays there. The (electric) fan is on a thermostat in the side of the block, kicks in at 190. The sensor for the gauge is in the intake manifold. I don't know what thermostat is in the water neck.


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  3. Kerrynzl
    Joined: Jun 20, 2010
    Posts: 2,284

    Kerrynzl
    Member

    Unbolt the hood and take it for a drive and see if it runs cooler!
    The heat needs to be transfered somewhere and if there is no airflow it will slowly cook.
     
  4. Ehlien
    Joined: Mar 18, 2015
    Posts: 100

    Ehlien

    I see that's a single pass ..I was looking at the same but an 18" double pass mounted in a similar area.
     
  5. Clik
    Joined: Jul 1, 2009
    Posts: 1,748

    Clik
    Member

    Correct me if I'm wrong: Water boils at 212 degrees at sea level. It boils at a lower temp in Denver Colorado. But that's in an open pot. If you pressurize the pot. the water temp can be raised higher without it boiling. Anti-freeze/coolant boils at an even higher temperature than water, although it doesn't transfer heat as well. When water boils in a block there are bubbles and wherever there's a bubble no water is touching the metal. That ain't good. Antifreeze makes a slippery and flammable (yes it burns) mess at race tracks so antifreeze may be a big No-no there and 180 degrees seems to be the optimal temp for drag cars on water. But adding coolant raises the boiling point and allows engines to run hotter without creating those problematic bubbles. This is also good for reducing emissions, as is running lean, which also increases heat. So, comparing a drag car running water to your soccer mom van on coolant isn't a good comp. The higher pressure the cap, the higher temp your car can run without the damaging bubbles. But just because your gauge reads 210 that doesn't mean there aren't hot spots in the engine where a bubble has formed. That's why 180 seems optimal on water in a drag car. Also a simple trip down physics lane will debunk the myth of water flowing "too fast" through a radiator. If your personal experiences have been otherwise I would suggest you look at other variables that would account for it because the molecules don't care.
     
    LostBoy and gimpyshotrods like this.
  6. Clik
    Joined: Jul 1, 2009
    Posts: 1,748

    Clik
    Member

    PS. No room for more radiator or fan? What about a remote oil cooler and larger capacity filter. As mentioned previously get the tranny cooled somewhere besides the rad. Plate type cooler with fan?
     
  7. Clik
    Joined: Jul 1, 2009
    Posts: 1,748

    Clik
    Member

    PS #2: How did you escape the wrath of the HAMB Gods posting about a late model Euro car? They must be sleeping this Sunday. ;)
     
  8. hotrod--willys
    Joined: Dec 15, 2009
    Posts: 512

    hotrod--willys
    Member

    Ehlien. A simple test. Go to a higher octane fuel. My Willys needs a little higher octane to run cooler. I run 92 octane without ethanol. My fuel tank is 15 gal. I cut in 1/3 with 105 octane race fuel. My engine then runs with no detonation problems. I cut temperature 20 deg. Doing just this.
     
  9. ghornbostel
    Joined: Jan 3, 2012
    Posts: 131

    ghornbostel
    Member

    A Buick V6 in a TR3 Triumph is a tight fit. I bought a bigger stock radiator to solve a heating problem. What worked was a aluminum cross flow. A fan that pulls is much better than a pusher. The problem that I had was after shut down is heat in the engine would percolate the fuel in the Weber carbs and cause a flooding condition even after louvering the hood. I had a 12" electric fan that I mounted on the frame so that it would draw air from under the front of the car and blow the hot air coming through the radiator out. It solved the flooding problem too because the fan runs after shut down till the controller says the temp is at 180 degrees



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  10. 1946caddy
    Joined: Dec 18, 2013
    Posts: 1,341

    1946caddy
    Member
    from washington

    From the picture, your blocking over 50% of the air entering your radiator. I would take the radiator to someone that can lower the top tank down about a inch or whatever you need to move the radiator forward and install an electric fan and shroud setup in the rear. Your not going to get a mechanical fan on your water pump the way you have your belt setup to the alternator.
     
  11. Quoting Ehlien : "The engine is lower than the rad so I have a filler block on top of the intake above the thermostat to make this the primary fill point and the high point in the system."
    If the engine is LOWER than the radiator, then the radiator is HIGHER, so why the need for a filler block at the thermostat ?
    The radiator would be the HIGH point.
     
  12. 19Eddy30
    Joined: Mar 27, 2011
    Posts: 877

    19Eddy30
    Member
    from VA

    X2. & if lean temp's go up,
    If Ethanol blind fuel or @ the pump gas is used ,( gas station )
    Looking @ plugs will give a False reading ,
    A wide band live O2 is required
     
  13. MIKE STEWART
    Joined: Aug 23, 2016
    Posts: 216

    MIKE STEWART

    I am running the same water pumps on both cars - Ford Motorsports short v belt pump. Stewart pumps in the past made them - for Ford - not sure if that is still the case. I need the clearance.
     
  14. Ehlien
    Joined: Mar 18, 2015
    Posts: 100

    Ehlien

    wow ..very interesting
     
  15. Ehlien
    Joined: Mar 18, 2015
    Posts: 100

    Ehlien

    thats thinking out of the box!
     
  16. Ehlien
    Joined: Mar 18, 2015
    Posts: 100

    Ehlien

    The top of the intake is 1 /4 lower but when you put thermostat housing on it the housing and the top rad hose is higher and thus a possible place for air to get trapped hence why I went to a filler block to make it higher and the fill point.
     
  17. Ehlien
    Joined: Mar 18, 2015
    Posts: 100

    Ehlien

    Well the Britts have gear heads too!!
     
  18. Is that a myth? I don't know, can the coolant flow too fast in radiator so that the heat cannot sink into the metal of the radiator and be carried off in the air? would you explain?
     
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  19. Ehlien
    Joined: Mar 18, 2015
    Posts: 100

    Ehlien

    The picture may not be the best representation.With the hood down I think the front entry of air is pretty good and the rad is unobstructed however some improved ducting could probably help. If the pusher doesn't get the job done I will be looking to try and modify somehow for a puller. No way I can ever modify the car to get the motor and rad line up to use a mechanical fan.
     
  20. Ehlien
    Joined: Mar 18, 2015
    Posts: 100

    Ehlien

    Don't know ..I'd like to know for sure also.
     
  21. Ehlien
    Joined: Mar 18, 2015
    Posts: 100

    Ehlien

    I got a suggestion from another site I thought was good to add a bypass hose from the top of the water pump to the intake which allows flow until the thermostat opens a bit.
     
  22. G-son
    Joined: Dec 19, 2012
    Posts: 504

    G-son
    Member
    from Sweden

    46international likes this.
  23. dicer2000
    Joined: May 25, 2016
    Posts: 69

    dicer2000
    Member

    I have quite a bit of experience with large cooling systems in the Navy. It's true that time is a component in the Heat Transfer Conduction formula. So, it seems that even from a fluid theory standpoint, this should be true.

    However, in closed loops (such as this), speeding up coolant in one place, speeds it up everywhere. So, per pass, water moving faster through the radiator decreases heat transfer in the radiator, but it also decreases it in the block per pass. Overall, the whole system would transfer just about the same amount of energy (both heat in and out) in a given amount of time.

    In fact, after fully stabilizing out, the overall system temperature will be the same as if it was running slowly. The only caveat here is that a larger pump [for increased water flow] will put quite a bit of heat energy in the water (including the energy of the engine working harder to run the pump.) Think about this: pumps are good if they are 50% efficient! And their inefficiency goes 100% to heat -- yipe!

    The only things you can do are:

    a) Increase rate of secondary conductive fluid (better air flow)
    b) Larger conducting area (larger radiator, more passes, better fins)
    c) Reduce corrosion layers (with a good cleaning)
    -and-
    d) Never, ever, let it boil! (Then you are dealing with a really crappy conductor)

    Thanks for the interesting thread, HAMB.

    PS. I have much more experience in 40,000 HP submarine power plants than "small" 600HP V8's. So, please don't flame me. :)
     
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  24. 28dreyer
    Joined: Jan 23, 2008
    Posts: 1,085

    28dreyer
    Member
    from Minnesota

    All correct. Nothing transfers heat better than pure water and flowing too fast is not a factor. Also brass radiators transfer heat better than aluminum and will hold a 18# cap. Aluminum is stronger and will hold a 28# cap.

    Air flow through the radiator is paramount and the framework of pusher and puller electric fans is a detriment to air flow as is too many fins per inch in the radiator which might be a good reason to stay away from serpentine fins versus straight fins, then all this air has to get out from underneath the hood or you are impeding air flow through the radiator. Make sure all air entering the grille opening has no where else to go but through the radiator.
     
    Last edited: Oct 4, 2016
  25. F&J
    Joined: Apr 5, 2007
    Posts: 13,132

    F&J
    ALLIANCE MEMBER

    Thanks for adding to the mix here... I dissected your long post and selected a few sentences...

    If we go by those alone, can we say that in certain specific systems, we "can" see a difference by slowing the water flow, like Chrysler "apparently" did with the special A/C-only pump in the 1970s?

    .
     
  26. blowby
    Joined: Dec 27, 2012
    Posts: 5,726

    blowby
    Member
    from Nicasio Ca

    Interesting stuff, and it's got me thinking I may have to get out the sawsall..:eek:

    My heap runs hot. I can take the whole front end sheet metal off and drive around which helps a lot. I have slots on the hood sides, a hole in the hood where the carbs are and no inner fenderwells so plenty of places for air to escape. But the grill, originally passing air to a small radiator and 750cc four banger, now serves a much larger radiator (as wide as the front of the hood and top to bottom) and engine. I wonder if it's inhibiting flow? It's integral with the shell, I would have to cut it out and replace it with something less restrictive.

    0227151741.jpg
     
  27. G-son
    Joined: Dec 19, 2012
    Posts: 504

    G-son
    Member
    from Sweden

    Doesn't look too bad, perhaps a bit small, but then again, looks can be deceiving. Perhaps you could "scoop" air in from below the shell, if you need more flow?

    A rule of thumb from a few books on my shelf (aerodynamics and engine tuning books) says that the air inlet to the radiator needs to be approximately 25% of the size of the radiator core, the tubes and fins in the radiator restricts air flow through the radiator so you can't force more air through it by having a bigger air inlet.
    As any other rule of thumb it oversimplifies things, but it's a good size to aim for. At higher speeds you feed more air through a smaller opening so it doesn't have to be as big, at low speeds you may need a bit larger opening to get sufficent air flow (or when it comes to cars used on the street, a fan).
     
  28. blowby
    Joined: Dec 27, 2012
    Posts: 5,726

    blowby
    Member
    from Nicasio Ca

    Thanks for the input. Wow, only 25%, I would have guessed more but looking at modern cars they don't appear to have any more. The lower scoop is a great idea, I will try that in carboard. My grill bars, instead of being round, are flat fronted and about 1/2" wide, probably not the most efficient, combined with their rearward slant. I could drill 3/8" holes in them.. I could also conceivably make cardboard air dams on the sides between the headlights and grill bars. I also have about an inch of air space between the top of the radiator and the hood, and maybe 1/4" on the sides I could block off for testing.

    Thanks again!
     
  29. travisn706
    Joined: Oct 28, 2013
    Posts: 49

    travisn706
    Member
    from Georgia

    It isn't, a triple pass rad. makes the water pass 3 times through the radiator to allow for the water to stay in the rad longer for cooler temps.
     
  30. 28dreyer
    Joined: Jan 23, 2008
    Posts: 1,085

    28dreyer
    Member
    from Minnesota

    P1060358.JPG P1060360.JPG View attachment 3343108
    I have effectively used pieces of closed cell foam rubber friction fit to close off air by passes.



    The most effective single pass radiator might have multiple rows of tubes but staggered, not tubes immediately behind other tubes. See photo and compare original core I had made with 4 rows of tubes totaling 96 with 15 fin per inch serpentine which created an air flow problem to the 3 row staggered 46 tube core with 8 flat fins per inch that cured the problem letting more air flow. A $325 lesson.
     
    Last edited: Oct 4, 2016

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