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Valve guides

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Adub, Sep 18, 2002.

  1. Adub

    Adub 1/2 ton status

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    My 89 TBI 350 has been using some oil. The engine only has 124k on it. It blow a quick puff at start up when it has sat for a few hours. It blows smoke at high rpm shifts or when you are turning and on the gas. My guess is valve guides. How difficult are they to replace?
    Thanks
    AW
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    If I recall correctly (and from looking at my Vortecs) there is nothing to repair on valve "guides". Not sur eif all stock heads are this way or not, but the Vortecs apparently don't have any sort of bushing, its valve on cast iron head. Shops either knurl the existing metal (bad) or ream out the head and press in actual bronze or whatever guides.

    A lot of your problem might be from the actual valve seals, as they are notorious for leaking, but high RPM smoke is typically from a worn out engine. (read, excessive tolerances in the cylinder bore)
     
  3. Shaggy

    Shaggy 3/4 ton status

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    <font color="green"> The valve seals are pretty dang easy. Any shop manual should be able to lay out the process, but it's basically a matter of removing the rockers and valve springs and pulling the selas off of the vavle stems, then putting on new ones. It's a time consuming the first time, but not hard. You will need an adaptor to pressurize the cylinders (1 at a time, the one you're working on) so the valves don't drop into them when you pull the springs, or you can do the poor-man's version, get some clean nylon rope and stuff it into the cylinder through the spark plug hole. I used the rope method when I replaced my valve springs and it worked fine.

    That being said, it sounds like your problem may be the rings, and that's a whole other can of worms...</font color>
     
  4. Adub

    Adub 1/2 ton status

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    So is it a valve seal problem? I doubt the engine is worn out, it still makes great power and runs just fine, it just smokes every now and then. I am contemplating swapping over to Vortec heads and TPI, but we'll see
    AW
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Mine makes great power too, but burns oil over 3000RPM, smokes on startup, and rattles because the timing chain and/or gears are hitting the cover. Its nice and loose, get great mileage on it, but its soon to be replaced. I hope. (damn shop)

    Working on the Vortec/TPI swap myself, so we might be in the same boat shortly /forums/images/icons/smile.gif
     

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