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Universal Fan Shroud Mounting

Discussion in 'Builds and Fabricators Forum' started by FinoCJ, Apr 1, 2020.

  1. Apr 1, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
    Messages:
    5,593
    I bought one of these cheap universal fan shrouds for the wagon to see if it will help with the tendency to start running warm when sitting in traffic (quite common in Denver). something like this:
    JEGS Chrome Fan Shrouds | JEGS

    I think I can get it to fit reasonably well...but have two questions:
    1) The 'universal' mounting system using plastic threaded 'push-thru' pins that go through the radiator fins and are held/tightened using wing nuts with rubber and plastic washers. I am not sure how well this works...anyone used them? I was thinking of trying to fabricate some sort of bracket/metal straps that would allow me to mount the shroud to the mounting rim of the radiator.

    2) ok - this one I am not as concerned about the more I think about it, but...anyone see an issue with it not being 'symmetrical'? That is almost a stupid question as since its designed to be something of a semi-circle - symmetrical doesn't really make sense. In a 'perfect' picture world, the shroud would cover the upper/top half semi-circle (or more - maybe 8 to 4 on a clock face) around the fan, but due to realistic engine compartment with sbc swap etc, the fan is not particularly well centered behind the radiator and is shifted towards the passenger side such that the fan blade extends quite a bit beyond the edge of the radiator on the passenger side. Plus, the relocated battery tray is in front passenger of the engine bay and limits space etc behind the passenger headlight. But I think I can get a pretty good fitment around the fan going from about the 2-3 oclock position on the passenger side, over the top to the 7-8 o-clock position on the driver side. It seems to fit the fan nicely and keeps a good portion of the radiator flowing air etc, and I think it should work pretty well. (I removed the flat/air block section that would usually go along/above the top of the radiator.)

    Here is a little mock up....I need to cut a few inches off the the passenger side where the shroud would terminate at the edge of the radiator fins.
    [​IMG]
     
  2. Apr 1, 2020
    Dphillip

    Dphillip Member

    Omaha NE
    Joined:
    Nov 25, 2008
    Messages:
    322
    My opinion:
    I’m not a fan of the plastic pins through the radiator fins. Your shroud should be pretty light and work fine but I’ve seen shrouds with electric fans attached to radiators with those pins and they’ve distorted the fins.

    Even with your mounting limitations a shroud is always better than no shroud. I’ve read that there is quite a science relating to fans, shrouds and wind characteristics. For optimum performance the fan blades should be halfway into the shroud and halfway out and there should only be one inch of space between the edge of the fan blades and the edge of the shroud. Apparently it the tips of the fan blades that generated all the wind flow.
     
    Last edited: Apr 2, 2020
    FinoCJ likes this.
  3. Apr 1, 2020
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member

    Bozeman, MT
    Joined:
    Jul 18, 2013
    Messages:
    5,593
    Well...I tried the push-pins....and did some cutting on the shroud:
    [​IMG]

    After doing it, here are my thoughts: I don't mind the push-pin part so much, and the light shroud is solidly held in place...but the plastic threads and washers leave a lot to be desired. It doesn't take much to destroy/strip the plastic threads and wonder how long they will hold the shroud in place. Thinking of replacing the plastic push-pin with some small machine screws or like 1/4" bolts and better washers to go with the rubber washers and wing nuts - or maybe just use some nylock nuts in place of the wing nuts. Now that the plastic push pin has safely made the the 'hole' through the fins, it would be simple to replace with something a bit stronger. Of course, new bolts requires a trip to the hardware store....not my favorite activity right now...
    I tried to follow the same guidlines you mentioned in terms of shroud placement...Its not perfect, but I think its pretty good and hopefully it won't take much to keep it cool....With the radiator moved to the proper forward position, the blade sits about right in terms of depth - the edge is right about half the blade:
    [​IMG]

    And I probably have a bit too much gap around the outside circumference - its probably 1.5-2" instead of 1" but still seems pretty good:
    [​IMG]

    I will put up some more pics and details in the build thread...moving the radiator to the proper forward position has some other dominoes that may need attention....
     
    Last edited: Apr 1, 2020
  4. Apr 1, 2020
    Dphillip

    Dphillip Member

    Omaha NE
    Joined:
    Nov 25, 2008
    Messages:
    322
    Looks good!
    I think you’ll, have noticeable improvement!
    That’s an interesting fan with the curved tips like that?

    I ran an electric fan for years and it drove me crazy, I tried multiple sensors and controllers but I could never get the fan to turn on and shut off at my preferred temperatures. Additionally, creeping along on the trail the fan would cycle every few minutes and really annoy me. I switch to a factory clutch fan and made a shroud out of fiberglass and now the motor stays at 190 degrees in all conditions.

    This is the link that I used to make my fiberglass shroud if your interested.
    Making a Custom Fan Shroud - Route 66 Hot Rod High
     
    FinoCJ likes this.
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