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Fan And Clutch

Discussion in 'Intermediate CJ-5/6/7/8' started by quimbypond, Apr 29, 2013.

  1. Apr 29, 2013
    quimbypond

    quimbypond Member

    Maine
    Joined:
    Aug 23, 2012
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    117
    I'm finishing off a few small things like a fan shroud(WTB in classified), and noticed that my fan has no clutch and might not be original. What size is original in a 304?? Is there a clutch and fan combo that will give a little more punch?? Maybe a stock clutch with a larger fan?? Opinions................
     
  2. Apr 30, 2013
    DREDnot

    DREDnot Not new to JEEPS

    AZ
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    Feb 7, 2010
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    646
    You got a pic of your current fan?

    I want to say that the heavy duty cooling option gave you a fan shroud and fan clutch.
    I'd stay with a stock diameter fan and new fan clutch and with the shroud, you'd have the HD cooling option.
     
  3. Apr 30, 2013
    quimbypond

    quimbypond Member

    Maine
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    Aug 23, 2012
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    Thanks DRED, sounds reasonable. The problem I have, is that I don't think my fan is stock. What size is a HD stock fan for the 304?? If I have to replace the fan, should I go with a lighter "flex" style fan??
    Also, I have a few clutches that were pulled from a 258......Will they work??
    Thanks
     
  4. Apr 30, 2013
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
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    Jan 15, 2011
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    Find yourself a ford contour fan, it's a dual électric fan that is simply the same dimension as the 304 radiator.

    I'm running with one since two year and i paid 30$ from a junkyard.
     
  5. Apr 30, 2013
    2manytoys

    2manytoys Member

    minnesota
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    Mar 28, 2007
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    282
    Flex fans are junk. They make a lot more noise and don't seem to move more air. I have a 360 with a stock fan and clutch from a wagoneer. No shroud and no overheating.
     
  6. Apr 30, 2013
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
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    If by flex fan you mean the contour one i talk about, you may be right about the sound but the suck lot's of air. With oem fan and clutch engine was always overheating, with the contour whatever i do, engine stay below 190 F.
     
  7. Apr 30, 2013
    quimbypond

    quimbypond Member

    Maine
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    Aug 23, 2012
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    Good info. do you know if a stock clutch from a 258 is the same as a 304?? some aftermarket retailers list them as the same.
     
  8. Apr 30, 2013
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Aug 10, 2003
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    Avoid the flex fans. The blades will cut you, and they sound like a hurricane. Stick with the factory fan and a thermal clutch, or go electric. Electric has the advantage that you can turn it off for water crossings.

    According to my book, sixes never got the fan clutch prior to 1981. It was only supplied for the V8 with HD cooling. All others had fixed fans (noisy).

    My CJ-6 has the seven-blade fan and a fan clutch, but I suspect it is not factory. It interferes with an aftermarket fan shroud, and it had an aftermarket-looking brand sticker on it (Flex-A-Lite? Something).
     
    Last edited: Apr 30, 2013
  9. Apr 30, 2013
    2manytoys

    2manytoys Member

    minnesota
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    Mar 28, 2007
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    no, the flex fan is a gimmicky fan sold at auto parts stores that is solid without a clutch. Real loud and doesn't move much air.
     
  10. Apr 30, 2013
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
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    I can say with electric, the day you're water pump bearing worm out, the fan won't destroy you're radiator...

    happened to me two year ago, that's the main reason why i went with contour fan...
     
  11. Apr 30, 2013
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Electric seems like a good upgrade - but wear your best build-for-reliability hat when you install it. If it quits, you'll be stranded, because the engine will overheat at idle.
     
  12. Apr 30, 2013
    quimbypond

    quimbypond Member

    Maine
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    Aug 23, 2012
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    OK, no flex fan. if I stay with a wagoneer fan and clutch, what should the space be between the radiator and fan?? I'm sure this matters in order to actuate the clutch properly.
     
  13. Apr 30, 2013
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
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    Oem fan, when the water pump bearing worm out, say goodbye to the radiator
     
  14. Apr 30, 2013
    quimbypond

    quimbypond Member

    Maine
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    Johneyboy,
    Screwed if I do, screwed if I don't!!!! If the electric fan quits, I'm stranded.....If the pump bearing quits, I'm stranded and dumping antifreeze. Any idea on fan/radiater spacing???
     
  15. Apr 30, 2013
    DREDnot

    DREDnot Not new to JEEPS

    AZ
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    First thing you want to make sure you have a new water pump. That way you don't have to worry about any of that.

    Second, mount the shroud.

    Now, with a new fan clutch (for the 304), you can use any good condition fan that fits the clutch and has about a 1/2" clearance between the fan tips and the shroud. The ideal spacing of the fan relative to the radiator will have the fan tips centered inside the shroud opening. That draws maximum flow through the radiator without any backflow (any air flowing back around the tips and into the front of the fan again).
    Here's an example on my 88 MJ
    [​IMG]

    Be advised that new motor mounts may be needed as they position the fan properly in the shroud opening and limit the motor from torqueing enough to have the fan strike the shroud.

    A new, correct fan clutch, and shroud, are the best way to go for reliability, cooling capacity, and HP (when less than locked up) That's why the factory uses them.
    The only drawbacks are parasitic HP draw when locked up when hot and slow, and the inability to turn off for deep water crossings.
    The electric only option draws the least HP, and can be turned off, but tends to be a little less reliable in non OEM / aftermarket installations and usually doesn't flow quite as much air.

    My 74 CJ 258 has the old fashioned fixed X fan without a shroud and does just fine. I'd put in a shroud with a clutch fan just to cut down on noise but there is not enough clearance for the clutch as there is only 2 1/2" from the water pump to the rad.

    My 99 Cherokee had, and my 2012 Cherokee has both a mechanical clutch fan and an electric fan. That suits me just fine as cooling and reliability trump deep water crossing here in AZ.
     
    Last edited: Apr 30, 2013
  16. Sep 18, 2017
    boxer

    boxer New Member

    Western Washington
    Joined:
    Sep 17, 2004
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    47
    Here is what happened to my Stainless Steel Flex Fan about 2 months ago. Broken blade. 21082895_10212093755591547_7292967464070678270_o.jpg
     
  17. Sep 18, 2017
    Desert Runner

    Desert Runner Member 2024 Sponsor 2022 Sponsor

    Hickory, Pa
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    Interesting ..... I had considered a flex fan. Went with twin 12" electric fans. Had them for about 15yrs, put the original fan and fan clutch back in two yrs ago. Meh

    Jay
     
  18. Sep 18, 2017
    boxer

    boxer New Member

    Western Washington
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    Sep 17, 2004
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    47
    Yes after the broken blade I installed a Flex A Lite 575. It seems to work good so far.
     
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