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Technical Thermostat/radiator question

Discussion in 'Traditional Hot Rods' started by Dan Fraser, Jul 29, 2017.

  1. Dan Fraser
    Joined: Jul 20, 2017
    Posts: 21

    Dan Fraser

    I have a 31 ford coupe with a 402 big block chevy and a traditional style radiator (year is completely unknown and I didn't think enough to take pics. The car isn't at my house at this time). Inlet is in the center, with the fill tube on the passenger side. The overflow tube is in the middle on top, and runs to the driver side, then down the side of the radiator. When I got the car (sat 24 years), there was no thermostat. I have one at 180 and it spewed about 2-4 qts out the overflow at 220 degrees (180 degree thermostat). My dad thinks it might suppose to be running with no thermostat at all, but I've read you need a thermostat so the water stays in the radiator long enough to get a chance to cool down.

    Eventually I'll probably change the radiator to something that'll cool much better, but for now I'd like to make this one work (tight budget), and I'd just plain like to learn more about it. Any insight would be awesome


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  2. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,752

    dirty old man
    ALLIANCE MEMBER

    I hesitate to ask, but are you sure you put that thermostat in right side up? That is the coil goes down towards the engine. There's all sorts of stuff could cause this. What sort of fan setup and distance from fan to surface of radiator? Shroud?
     
  3. Babar40
    Joined: Dec 4, 2009
    Posts: 313

    Babar40
    Member
    from Florida

    Welcome to the HAMB Dan! I'm sure one of the many qualified folks will get you straightened out.
     
  4. squirrel
    Joined: Sep 23, 2004
    Posts: 47,124

    squirrel
    Member

    Might not have had all the air out of the system. I would add more coolant, fill it to just above the tubes in the top tank (down a few inches below the filler neck), and bring it up to temperature again and see how it does. Maybe open a plug or heater hose (if it has a heater hose) in the intake manifold, that connects to the cooling passage, to help you get the air out of the engine as you fill it.
     

  5. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 25,505

    Jalopy Joker
    Member

    squirrel likes this.
  6. Dan Fraser
    Joined: Jul 20, 2017
    Posts: 21

    Dan Fraser

    Have no good pics right now, but I'll get some soon as I can. Thermostat is installed correctly (funny you mentioned it cuz I had a brain fart and had to look it up cuz I couldn't remember for some reason lol). Right now there's no fan or shroud (yes I know, that needs addressed soon. Looking at either a flex fan or electric, but still undecided right now). Can look down the neck, as it comes out the back side and curves up instead of being right on top like I'm used to. When I ran started it up, it took forever to get warm with the cap off (fluid cool to the touch). Put the cap on and within 10 the thermostat opened, and within 5 min of that it was coming out the overflow


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  7. You have NO fan?????????
     
    lothiandon1940 likes this.
  8. Here's a pic of the radiator that Dan posted in his other thread. Appears that it might be a '55-'57 Chevy Harrison model with filler neck modified so a radiator shell could be used. Dan, you need to figure that fan arrangement out or put a house fan in front of the car while you do more testing of the thermostat situation. Others may correct me on the origin of the radiator. f0dd8f7c1ce3b1fd4ff2b60c48f8c007.jpg
     
    lothianwilly71 and Dan Fraser like this.
  9. Dan Fraser
    Joined: Jul 20, 2017
    Posts: 21

    Dan Fraser

    Not yet. It's not street legal, so it don't even leave the driveway. Only runs a few minutes at a time


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  10. Dan Fraser
    Joined: Jul 20, 2017
    Posts: 21

    Dan Fraser

    Hell I never even thought of that one! Just needs something to push air thru it, so that would prolly work just fine. Thanks for the tip!


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  11. Dan Fraser
    Joined: Jul 20, 2017
    Posts: 21

    Dan Fraser

    Had my buddy sent a couple pics he took before we got it mounted. [​IMG][​IMG][​IMG][​IMG][​IMG]


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  12. Did you do a flow check n the radiator?
    Did you try to flush radiator before installation?
    I always do the following before trying to install a used radiator.
    Remove the radiator. put cap on and place radiator up-side down on a 5 gallon bucket. place garden hose on the outlet side and turn on. This will reverse the flow from installed coolant flow. With the water running does the water come out the inlet which is now down at bucket. What does the water look like? are you seeing a lot of debris, dirt, sand in the bucket? Finding dirt and debris, that is no bueno. Is the water going through radiator or coming out the outlet port, now up high where the hose is installed? Also, no beuno.

    If radiator is bad check out Griffin, RatRod series radiators

    http://www.griffinrad.com/RatRods/index.php?tid=14
     
  13. Looks like about half of your air passages are closed off from the photos.
     
    Nailhead Jason likes this.
  14. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,752

    dirty old man
    ALLIANCE MEMBER

    That radiator appears to me to be likely a Mopar, as I notice it doesn't have tubes and fins like an old Ford. Can't recall the technical name for that type radiator construction and it's a method I don't think is used anymore.
    I agree a strong house fan placed so that it will blow thru the radiator will help. I usually use one in addition to fan on engine for the initial startup on an engine when I build and first start, helps keep things cooler while you're setting timing and otherwise getting the tune correct.
    Strongly suggest not using a flex fan, as they quite often don't do the job. Use the biggest diameter steel blade fan you can fit with as many blades as you can find. A shroud will help, especially if the fan blades are more than 3/4" from radiator core.
    Electric fans come in all sizes, shapes, prices and efficiency and effectiveness, and as far as aftermarket goes, you get about what you pay for. By far the most effective electric OEM is the '93 thru '98 Lincoln Mark VIII. All the Fox body Mustang purpose built drag racers run them if they are savvy. But on a hot rod? I'll be honest, IMO if you aren't running a hood, you need to 'cause they look like shit:eek:
     
  15. Dan Fraser
    Joined: Jul 20, 2017
    Posts: 21

    Dan Fraser

    I flushed both the engine and radiator before instal, then attached the bottom hose and filled the radiator til water came out the intake. Everything appears to flow nicely. However I just thought of this one, I can't guarantee the water pump is pumping properly, as that is not a new one.

    I have opened a lot of those fins back up. Looks like a fan got into it at one point lol.

    As for the hood, it don't fit. From the firewall out, it ends at the front of the engine block. Hoods are always a personal preference anyway. For me, it all depends on the rest of the car and the look of the engine. I may have a new one made, but not fully decided yet.


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  16. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,995

    Blues4U
    Member
    from So Cal

    So, water boils at 212F at sea level. Add a pressure cap and that raises the boiling point ~3* per psi. With 4# cap installed it would not boil at 220*. Antifreeze also raises the boiling point, a 50/50 antifreeze/water mix raises the boiling point to ~226* with no pressure cap. Combine the 2 (pressure cap and antifreeze) and the boiling point increases even more. Here's a nice little chart that shows the boiling point depending on pressure cap and antifreeze ratio: https://durathermfluids.com/pdf/techpapers/pressure-boiling-point.pdf

    Old wive's tale. A stubborn one, keeps coming back around, but a myth nonetheless. Coolant moving faster will actually increase the rate of heat transfer. Still, there's no need to run without a thermostat, best practice is to use one, ~ 180 - 195 is good (I like 180).

    Big block Chevy's tend to run hot, they like lot's of air movement over the radiator, and they like lot's of coolant circulation thru the system. Get a decent fan and shroud installed, and still expect it to run warm at low idle, it's going to want to be moving down the road, not sitting and idling for long periods.
     
    Dan Fraser likes this.
  17. Dan Fraser
    Joined: Jul 20, 2017
    Posts: 21

    Dan Fraser

    Holy technical answer batman! Love it! Much better than the old "you should do it this way cuz that's what I do" type of answer. Definitely gonna be taking care of the fan issue soon


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  18. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,752

    dirty old man
    ALLIANCE MEMBER

    I don't think you understood what I meant when I said to put a hood on ito_O I was referring to putting an electric fan on a hot rod, and that being so ugly it needed to be covered up with a hood:):p:rolleyes:
     
  19. Dan Fraser
    Joined: Jul 20, 2017
    Posts: 21

    Dan Fraser

    AHHH. Gotcha lol


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