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BIG ALT @ LOW $$$ - *UPDATED* 102A @800RPM!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by KRAZIE87K5, Jul 24, 2002.

  1. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    I found out that ALL my recent problems are related to a weak ALT that cannot keep proper voltage at idle with my FERD FANS running. /forums/images/icons/blush.gif While that might be pretty COOL *if you will pardon my pun*, it sucks that it kills my electrical system. Its so bad that at times, the truck doesn't have enuf power to fire the ignition! /forums/images/icons/blush.gif /forums/images/icons/shocked.gif

    SO I need to know what ALT to buy. I've already got a 1050cca battery, so I don't think that is it. I don't have huge $$$ to spend... but I need as much power as I can get. What is my best choice? Thanks all! /forums/images/icons/laugh.gif

    -Dan
     
  2. bklynlifted

    bklynlifted 1/2 ton status

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    Re: Need a BIG ALT @ LOW $$$ :)

    check this site out should answer all your questions. web page /forums/images/icons/wink.gif
     
  3. chillywilly

    chillywilly Registered Member

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    Re: Need a BIG ALT @ LOW $$$ :)

    I was in the same boat last summer.I snagged a 105 amp alternator from a mid 80s buick lesabre. Cheap and it puts out 60 amps at idle with everything on !!! lol /forums/images/icons/cool.gif
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: Need a BIG ALT @ LOW $$$ :)

    Did it bolt in the stock brackets? How much will it put out total?
     
  5. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    Re: Need a BIG ALT @ LOW $$$ :)

    post #1... Hmmm... anywho... Does it fit in the factory location? You gotta let us know...

    -Dan
     
  6. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: Need a BIG ALT @ LOW $$$ :)

    I take it that reply was not for me, but the post above.
     
  7. HarryH3

    HarryH3 1 ton status Author

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    Re: Need a BIG ALT @ LOW $$$ :)

    Summit carries the Powermaster line. The 140 amp unit is pretty stout and as I recall runs around $200. Any more current than that typically gets you into the $380+ range. /forums/images/icons/shocked.gif
     
  8. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    Re: Need a BIG ALT @ LOW $$$ :)

    Check your local Motor rewinding shops.. I found a place local the buys new alt. and rewinds them. Stock puts out 40 at low and 60 to 65 amps at high end.. I bought a new rewound 140 amp alt for $140.00 it puts out 65 at low end and 140 amps at top end.. And it is the newer one.. One wire setup.. I am running 3 fans and 6 lights with a stereo and amp and it doesn't even fade out...Dan
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: Need a BIG ALT @ LOW $$$ :)

    Try bumping idle up a hundred or so RPM's and see if the problem is solved. I'll be able to tell you a difference (in volts only) of that smaller alt pulley (about 2 3/8" apparently, and $12 to my door) as soon as I get it. Whats your alt pulley diameter now? I measured all the ones I have, including the one I'm running (approx 2.5") and I happen to have an 87 amp unit that has a *3"* alt pulley on it.

    That 3" pulley will *seriously* cut down on idle output, and if you have a pulley that big, you'd be able to turn idle back to "normal" and still have the alt turning fast enough to make a difference if you went with a smaller stock pulley.

    Turning the idle up will take what, 2 minutes? All you have to do is go for a short drive and see if the problem is solved. Either that or put it in neutral and bring the RPM's up a hair with your foot. (or, if it isn't a problem at cruise, that should be indicative that idle output is the sole problem)

    I see a *noticeable* drop (about 1-1.5V) with only a 100RPM difference. After that, the volts are rock steady right around 14.5. (about 550 vs 650-700RPM)

    Haven't read/heard a whole lot of bad things about the "better" aftermarket alternators, but I do recall a couple of problems (to be expected) with some bad units. Didn't check the previously listed link for alternators or whatever, but beware, some aftermarket units list *max* amp output only (which is what GM does) but of course, that isn't what you'll see at idle.

    Check your alternator, you may already have a fairly large amp one. Unless its been rebuilt, it should be stamped on the alternator case along with some other numbers and letters. Not sure if this is normally visible with the alt in the truck though or not. (seen 37 and 44 amp units though, so you best check lol)

    FWIW, with a little bit of work, the newer Camaro alternators (120Amps I think?) will fit, and might be cheaper than the aftermarket units..at least they should be more commonly available. I can find that info if you are interested, but I'd go the cheap route first.
     
  10. Parf

    Parf Registered Member

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    Re: Need a BIG ALT @ LOW $$$ :)

    4WPW. Powermaster 140amp alt. $140.00
    They are allways running a free shipping deal...
    I run one in my Jimmy, and one in my 67 Landcruiser with quad electric fan setup and it draws about 45 amps alone at idle. Worth every penny.
     
  11. BobK

    BobK 1/2 ton status

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    Re: Need a BIG ALT @ LOW $$$ :)

    I got the Summit brand 140amp,1 wire alt.Got it for $169.99.I ran into the same problems when I installed by dual 14" electric fans.My old 100 amp wasn't cutting it at idle.
    Just to mention PowerMaster wants like $250.00 plus for thier 140amp alt. and they actually make the $169 dollar Summit brand.When I filled out the warrenty card for my Summit Alt. A couple months later I got a recall notification from PowerMaster telling me there was a prob. with the alt.
    Anyway they test the alt's before they send them out and this is what mine tested at.
    No problems yet /forums/images/icons/grin.gif
    [​IMG]
     
  12. BorregoK5

    BorregoK5 1/2 ton status

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  13. Parf

    Parf Registered Member

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    Re: Need a BIG ALT @ LOW $$$ :)

    Chevy Late Model Small Case 140 Amp
    [​IMG]

    This is the most popular late style Delco alternator. Shown below are a sampling of some of the mounting configurations we offer. In the near future, we hope to have an application guide online. In the mean time, to determine the correct part number for your specific application, please contact us for assistance. Thank you!
    Features:
    Excellent Output at Idle
    Gold Battery Post
    Proof of Performance Tag
    Upon ordering we will ensure you receive the correct Alternator. Note: Pulley not included, you must reuse your pulley. <font color="red"> (Both the powermasters I bought came with pulleys) </font color>
    Part Number Description SRP Your Price Add to Cart
    POW47294 140/80 Amps $198.95 $157.95 Add to Cart
     
  14. ken

    ken 1/2 ton status

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    Re: Need a BIG ALT @ LOW $$$ :)

    I got a new Powermaster 100 AMPer (about $100) and at the 100 day mark it quit working...wouldn't ya know it, just outside of the 90 day warranty!!
     
  15. chillywilly

    chillywilly Registered Member

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    Re: Need a BIG ALT @ LOW $$$ :)

    Sorry about the late reply...been swamped here.Yepits a direct bolt on..might have to tweak upper alt bracket a little lol.With my dual ferd fans on and lights and heater output is 60 amps at idle.Will put out 90 amps at 2500 rpm.Keeps batt voltage upto 13v even up here in frozen maine.lol /forums/images/icons/wink.gif
     
  16. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: Need a BIG ALT @ LOW $$$ :)

    My Buddy is running an alternator off a Semi. Thing is HUGE! It's rated about 220 amps. He got it for around $200 I think and had to do some pully work. It runs a V belt that is twice the size of what our trucks run. It's on a FJ40. He bought it at a truck repair place.
     
  17. m j

    m j 1/2 ton status

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    Re: Need a BIG ALT @ LOW $$$ :)

    I have been looking at those.
    can you get any more info
     
  18. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: Need a BIG ALT @ LOW $$$ :)

    I'll be seeing him Next Saturday. Might talk to him before then and try to find out some info. It's a Honker though! Not sure there is enough distance between the head to get it lined up with the existing pully location. Might have to relocated it a little outboard like they mount the pancake A/C compressors on the in the mid 80's. use a tennsion arm light the mid 60's GM cars used.
     
  19. m j

    m j 1/2 ton status

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    Re: Need a BIG ALT @ LOW $$$ :)

    anything you can come up with would be sweet, thanks.
    more as to what model he liked or electrical changes, the mounting looks like a pretty straightforward huge amount of work
     
  20. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    Re: Need a BIG ALT @ LOW $$$ :)

    WELL... I get back from vacation last night TOO excited to drive the rig to work today! /forums/images/icons/smile.gif Started right up, and hummed along happily in the driveway, after I disconnected ONE of the TWO Ferd fans (to reduce amperage draw to only 30A). Drove to the local McD's for some quick chow before work, and as I pulled into the drivethru, the dang thing sputters and dies - just like in the Jewel parking lot a day before I left for Florida! /forums/images/icons/frown.gif /forums/images/icons/mad.gif I'm guessing its the coil this time - hopefully since its only a $30 part! /forums/images/icons/wink.gif

    Now I'm in a crunch, and need to find a PowerMaster somewhere local. The McD's MGMT gave me till end of business to remove it from their lot! Bastards... /forums/images/icons/tongue.gif /forums/images/icons/laugh.gif ANYWHO...

    Guess I should start calling around!

    -Dan
     

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