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    Electric fan conversion

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    78i6belair
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    Electric fan conversion

    Post  78i6belair on Thu Jan 18, 2018 4:50 pm

    Hi there.

    I'm looking to replace my fixed 4 blade mechanical fan on my 1978 Bel Air that has the 4.1 (250 cid) straight 6
    engine.

    Has anyone converted their 1977-90 B body to electric fans before? I'm sure the whale cars (91-96) had them
    from the factory.

    Any info or help would be great.

    Thanks
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    Kit1078
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    Re: Electric fan conversion

    Post  Kit1078 on Fri Jan 19, 2018 11:07 pm

    I did a fan swap using a set of fans from a 1999 cadillac deville (I bought the whole assembly from the junkyard for about $40) I had to trim the cowling to fit the radiator and make a couple of mounting brackets. I've seen a couple places where the electric fan assembly from a 97 V6 cougar works, it's a two speed single fan assembly. I think Hot Rod Garage used it on a project once.

    I'm using a Hayden fan controller

    https://www.summitracing.com/oh/parts/hda-3653

    This uses a probe that you strap to the radiator. Since I have two fans, I wired it to a relay, tho it is rated to run a single fan without a relay. The only issue I've had is the draw on the alternator tends to make my car want to stall. I'm working on that last part.
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    78i6belair
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    Re: Electric fan conversion

    Post  78i6belair on Sat Jan 20, 2018 7:39 am

    Hey there and thanks.

    Seems to be a few GM and Ford vehicles to use the electric fans from. The Lincoln MarkVIII is a popular swap candidate and 3rd Gen F body V6 fans seem to have the right sized fan shroud to cover the rad core area.

    I am somewhat concerned at the amount of current that a dual electric fan set up will pull at full speed, however I have upgraded my charging system with a relocated voltage regulator sensing wire, 12 gauge main charge wire (original was 14Ga) and a GM 12SI 78 amp alternator from a 1984 Chevrolet Camaro. I also fitted a smaller diameter pulley to spin the alternator slightly faster then stock.

    With the electrical system at max load, I'm measuring with an amp clamp about 38-40 amps of current draw with the car in D @ 600 rpm.

    If a dual electric fan set up draws around 30ish or so Amps I should be okay.

    I'll look into a fan controller, do you think this can be done without one?

    What type or series alternator are you running on your B body car? What do you have BTW?

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    Kit1078
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    Re: Electric fan conversion

    Post  Kit1078 on Sat Jan 20, 2018 10:55 am

    I'm running a CS144 alternator from a late 90's chevy suburban with a 30% overdrive pulley to offset the 30% underdrive crankshaft pulley I'm using. (basically, it's running at stock speed, since the two cancel each other out). These alternators were used on conversion vans and tahoes or suburbans that had extra fancy packages, with lots of extra electronic stuff to draw on the alternator.

    You don't have to run a fan controller, but I'd strongly recommend it unless you want to have the fan running all the time. On my Impala, the fans only ever kick on if i'm sitting at a stop for more than a minute. I'm also running a stock replacement aluminum radiator (courtesy of Autozone) on a 350 with aluminum heads. surprisingly enough, those cheap plastic tank aluminum radiators seem to do the job ok.
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    78i6belair
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    Re: Electric fan conversion

    Post  78i6belair on Sun Jan 21, 2018 5:09 am

    Oh wow you've gone a step even further with the CS series alternator. I'm on a 2nd Gen Camaro forum and a lot of guys use those.

    It never really occurred to me how important alternator pulley size is to maintain correct charging system voltage, especially at idle.

    I'm most defiantly going to use a fan controller of some sort, I just don't want to have a big control box laying around the interior of my car.

    The one you showed me on Summit racing looks like a nice clean set up. I'd hate to have the fans run all the time once the engine got up to temp, would defeat the purpose.

    I snagged a electric rad fan assembly from a 1997 Camaro V6 from the auto wreckers yesterday, I'll post pics. looks like it will cover the rad core perfectly. It's a dual fan set up.

      Current date/time is Mon Oct 15, 2018 3:45 pm