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Now it really sucks....

Discussion in '40- & 55-Series Tech' started by Brian in Oregon, Aug 27, 2006.

  1. Brian in Oregon

    Brian in Oregon

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    The 350 V-8 in my FJ40 had a Flex-a-lite #1316 16" Flex Fan installed with a 1" spacer. (Radiator is stock.)

    The cooling was OK, but the temp would go up when in heavy traffic or wheeling.

    I replaced it with a #1318 18" fan (actually 18-1/4"), and a 2" spacer.

    Now you can actually feel air being pulled through the front of the mesh grill at idle. Couldn't feel that before. And when driving you can hear the fan noise quick clearly as the fan sucks the air in. There's a noticable increase in airflow in the engine compartment at all RPMs, and you can feel a lot more air coming out of the hood vents.

    The 18" fan now covers the core area from top to bottom, and side to side. It only missed the corners. The 19" fan, #1319, which is actually 19-5/16", would almost completely cover the corners as well. I was really tempted to install this fan, and there is enough clearance for it. It does come close, though, to the stock radiator fill cap neck, about 1" away, while the 18" fan is 1" away and 1" down. I'm not sure if severe body flex could cause the 19" fan to ever hit the filler neck, so I finally weenied out and went with the 18" fan.

    Ran the FJ40 around today. It was slightly hotter out today than yesterday. The cruising temp was slightly better. But the idling and slow speed temp was much better. About a good 10 to 15 degrees better, because the temp would just climb.

    I'm not sure if the fan size was that significant. It's possible a 16" might have been adequate, but I don't like to do the job twice, so I swapped it out. I think the main culprit was that the fan was simply too far away from the radiator, and was pulling some air in from the sides. In other words, it was partially recirculating hot engine compartment air.
     
  2. my64fj40

    my64fj40

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    Did you have a shroud with the flex fan?
     
  3. Brian in Oregon

    Brian in Oregon

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  4. Degnol

    Degnol

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    Unless it is a pusher, you really need a shroud. Shroud gets the "corners":)
     
  5. CRUZR66

    CRUZR66

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    Overheating Problems?

    A seven blade Cadilac fan out of a newer Caddy, works the Best I've found out, i ran Rubiton with out mine this year, OOps bad thing running Hot, Changed back to seven blade Works great, 5 blade in the Winter, 7 blade in the winter, i have a 66 fj40, 350 chevy, sm465,np205, with Dana axles with 39.5 iROK's work great now.
    CRUZR66
     
  6. my64fj40

    my64fj40

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    There was most of your problem
     
  7. Brian in Oregon

    Brian in Oregon

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    I'm planning on adding sheetmetal "wings" to the sides, and will eventually build up top and bottom pieces as well. Goal is to eventually shroud it in. Wondering how much clearance I need to give the fan for frame, body and engine flex, though.

    Didn't realize any late model cars were still being made with engine driven fans. Thought those all went the way of the Dodo.
     
  8. honk

    honk

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    I know it's hard to take seriously but I used to know a guy who ran a 350 V8 in his FJ40 using a cutdown-to-fit Rubbermaid garbage can for a fan shroud. He really did such a good job that I didn't realize that it wasn't steel until I leaned on it.

    Fans use horsepower, and the higher effect you notice with the bigger fan means it uses more than your old one did. A good fitting shroud around your smaller fan, or one even smaller could give you good cooling with less HP loss.
    I know we're not doing racecars, but horsepower equals fuel in any engine.
     
  9. projektdotnet

    projektdotnet

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    Friend has a ford F250 with a shroud...no problem. Said shroud is damaged while trompin around friend's property and has to be removed...Truck starts overheating as soon as he fires it back up.

    Moral: RUN SHROUD
    (true story)
     
  10. bandy rooster

    bandy rooster

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    theres more reasons for a system not to cool properly then just the shroud...
     
  11. corsair23

    corsair23 SILVER Star

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    Hmmm...I call them "power sucking fans"...My Dodge is that way (yeah, I know, a Dodge?) and it inevitably kicks in and starts its power sucking right when you need all available power the most :mad:

    Oh, and they are some of the noisiest damn things out there...Sounds like you are preparing for takeoff!

    I've SERIOUSLY considered replacing it with an electric fan...
     
  12. Colorado Boy-74-FJ40

    Colorado Boy-74-FJ40 I may grow older but I refuse to grow up!

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    Flexalite dual 14" electric fans thermostatically controlled, Freed up about 20 horsepower in my truck.
     
  13. corsair23

    corsair23 SILVER Star

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    What vehicle and what was it on the banana scale to replace? I'm a 1 :banana: person, maybe a 2 :banana: :frown:
     
  14. rsc71

    rsc71

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    losing 20hp seems like a small price to pay for keeping your motor cool.I would run a manual fan if i could get it to fit.
     
  15. Brian in Oregon

    Brian in Oregon

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    I'm not particularly enamored with electric fans. Have two huge pusher fans on my 3/4 ton Chevy pickup, and they definitely will not cool the 454. Had to add a flex fan to the engine. Left the electrics in as auxilliary fans. They only come on when idling on very hot days.

    And, it still takes power to run the fans. Some of these fans draw a helluva lot of amperage. Your alternator still has to make up for that.

    The biggest advantage to electric fans is that they can shut down when the airflow is sufficient to cool the radiator, like at highway speeds, or during cooler or cold weather. And the fan(s) can be set up to keep running after the engine is turned off, to help cool down the engine compartment and prevent hot start issues. Also, electric fans are the ultimate version of "clutch fans", because the engine can rev much more freely with an electric fan.

    But to say that a clutch fan frees up X amount of horsepower, well, you really need to look at the load on the alternator. TANSTAFL - There Ain't No Such Thing As A Free Lunch.
     
  16. FJ40_owner

    FJ40_owner

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    No Efan!

    I have a 350 in my 40. I was running 220+ crawling and 210+ on the freeways. I felt an efan was my salvation. I spent nearly 300 dollars on a Summit 3500 CFM fan. Prior to the install I had the copper 4 row rad rodded out.

    Out of maybe 40 tubes ten were plugged. I was happy, maybe now my problem was solved. Silly me. I went ahead and installed the efan. I calibrated the controller to come on at 180, just as I calibrated my 180 stat. I figured the 40 would ride the stat @ 180, NOT!

    On an 80 degree day the efan would cool the 350 at idle. After that it was all downhill. I simulated crawling up a 45 degree hill at 5 MPH. Had to shut down, was approaching 230. Same on a 45-50 MPH run on a level rural road, near 230. WTF!!

    The efan seemed like it would "pull squirrels out of the trees." Lots of CFM. NOT!
    My Efan was installed snug up to the rad, WTF.

    Hell it was easy to rip that thing out and re-install the 6 blade mech fan. My mech fan sits about 2/3 of the way out of the shroud. I ran the same roads at higher OSA and never got above 200. I went wheeling this weekend, never got above 200.

    I still do not understand my perception that the efan was pulling gobs more air than the mech fan. There must be some physics going on that I do not understand.


    (All my gages are calibrated analog gages)

    Good luck

    JB

     
  17. Brian in Oregon

    Brian in Oregon

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    I won't go so far as to say ALL electric fans are bad. I defiinitely will not say ALL electric fans are good.

    I suspect that SOME electric fan makers are rating their fans for CFM flow with no load, meaning pure open air. You put their fan behind or in front of a radiator, depending on the model, and suddenly the advertised air flow drops like a stone.

    This is probably why SOME electric fans have a good following, and others don't. Some makers probably overrate their CFM flow.

    A classic example is the junkyard Ford Taurus fan assembly. It's spoken highly of here for conversions. We know from testimony that it works. Yet who knows what CFM it is really rated at?

    The dual fans on my 71 pickup were supposed to be the cat's meow according to the previous owner. Impressive CFM rating, blah blah blah ad nauseum. They simply weren't up to the job by themselves. They're adequate as auxilliary fans.
     
  18. Colorado Boy-74-FJ40

    Colorado Boy-74-FJ40 I may grow older but I refuse to grow up!

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    1 1/2 bannanna. I used the stock fan shroud and made a couple of brackets to attach the fan to. I attached to the cross member I don't agree with mounting directly to the radiator.
    fans.jpg fans1.jpg engine.jpg
     
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