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Alt question for you techies

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by NewK5Guy, Jun 23, 2001.

  1. NewK5Guy

    NewK5Guy 1/2 ton status

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    I don't know much about the exact makeup of the unit itself so I'm gonna need some help here.
    For those of you who don't remember, I'm eating alt v belts on my 84 6.2 diesel. I just can't figure it out. Well, I'm about to go through my 4th in as many months(this has lasted the longest), but I have a question.
    I'm replacing the head gaskets on my other car, so naturally, the alt came off. It's a 1992 Ford alt for serpantine belt. When I grab the pulley, there is no play at all, lateral or otherwise. it is tight and spins freely. When I grab the pulley of my truck alt, I can feel a bit of "free" movement. You can't see it, you can't hear it, but you can just feel it. Could that mean the truck alt is going bad(I have no idea how many miles are on it) or is this just a bad comparison? The truck's insatiable appetite for alt belts has to stop.
     
  2. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color=blue>More than likely the pulleys arent parallel with each other. One is further out then the other, which is causing wear on your belts. Lay a straightedge over the pulleys to see if they are in line.</font color=blue>
     
  3. surg82k5

    surg82k5 1/2 ton status

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    Just a thought on my '82 6.2 I can tighten up the alt belt really good and when i start it up you can see the belt has about 1/4 inch of play( up and down, not sideways: if that explains it). I can't say that my 6.2 eats up belts like yours but mine does seem to have play in it pretty close to what you describe.
    Sergio
     
  4. scrapmetal

    scrapmetal 1/2 ton status

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    While in desert storm we were having a problem with the 6.2's eating belts, not all just the ones that a dumbf$#@ mechanic had worked on, they all kept putting the pulleys out of alignment, I agree with the one fella, they are probably out of alignment, and as for the play, as far as I know, mine has none at all, they are supposed to be pretty damn tight. I have also seen people who tighten ther belts with a 6 foot cheater bar wedged in behind the alternator and tighten them too tight this also will smoke a belt, your manual should have the recommended poundage they are supposed to be set at, the diesels being a little tighter than a gas because of the heavy duty alternator, and electrical system,, anyways food for thought,,

    Never been stuck, just temporarily delayed.
     
  5. jarheadk5

    jarheadk5 1/2 ton status

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    "6 foot cheater bar wedged in behind the alternator..."
    Yeah, that'll kill the belt. It'll also kill the bearings in the alternator and put way more stress than necessary on the other components that belt passes over. I think the general rule of thumb for V-belts is 1/2" of deflection with a medium-effort push (20lbs force is the actual number I think).
    BTW, I also agree with the pulleys-out-of-alignment diagnosis.

    <font color=red>Click those banners and help support CK5!!<font color=black>
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  6. NewK5Guy

    NewK5Guy 1/2 ton status

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    I'll look into that out of alignment thing. A perfectly straight 3' edge is going to be hard to come by, but I'll see if I can get my hands on one.
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Mine likes to throw the belt off once in a while. It hasn't done it in a few weeks though.

    Tim
    '84 Chevy K10, lifted, loud, fast, and 3/4 ton axles
     
  8. HarryH3

    HarryH3 1 ton status Author

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    You can check it without a straight edge. If you stand off to the side of the truck and look straight along the length of the belt, you can see if the pulleys are out of alignment. It'll be pretty obvious if they aren't. The belt will look "bent" instead of perfectly straight.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://www.angelfire.com/super/ThunderTruck>http://www.angelfire.com/super/ThunderTruck</A>
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  9. txbartman

    txbartman 1/2 ton status

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    Do you know what the amperage rating on an alternator from a deisel K5 is? Mine is wimpy and needs to be upgraded. If I can get a deisel one from a junk yard versus buying a new higher amperage one, I'd rather try it. Anybody know?

    85 GMC Jimmy, 305 w/TH700-NP208, 4" lift, 32X11.5 BFG ATs, 15x10 Eagles, Smittybuilt tube nerf bars and bumbers
     

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