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Smoke

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by mud390, Jun 18, 2003.

  1. mud390

    mud390 1/2 ton status

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    Location:
    Little Rock, Arkansas
    Whenever I put my foot in it, there is a slight whitish blue smoke from the exhaust. If I really get into it, I get the whitish blue exhaust, then a little puff of black as it finally idles back down. Isn't the whitish blue a sign of burning oil? I know my truck needs a tune in a bad way. Could that be the cause of any of this? The motor is a 350 supossedly bored 30 over. Thanks.

    Kris
     
  2. BayouBlazer88

    BayouBlazer88 1/2 ton status

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    Yeah, sounds like you're burning oil. I'd say it's one of 3 things: 1) leaking head gasket, 2) leaking piston rings, or 3) leaking valve seals. Mine smokes white on startup but that's it. It's probably from oil seaping into the combustion chamber through my slowly leaking valve seals. Changing head gaskets and valve seals aren't nearly as hard as piston rings being that you have to pull out the engine to change piston rings.
     
  3. the professor

    the professor 1/2 ton status

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    Agree with the answer, but not with the order..
    --
    All cars, small block Chevy in particular.. suffer from "hardended valve seals" with age, and with leaking intake gaskets..
    --
    Small Chevys suffer in this area, because of and extreme amount of lubrication to the rockers and valve stem area..

    Chevys use two seals on the valve stem, an rubber "umbrella" seal on the stem, and a small "O"-ring seal on the stem that seals the valve spring retainer.. (The rubber "umbrella" seal, is not to be confused with the metal umbrella around the valve spring on some engines...)

    When they get hard, they crack and leak... usualy worse at idle, (hi-vacc) and decel...

    You can get ring smoke during decell, but you usualy get ring smoke at hi-rpm too...

    The stem seals and umbrella seals can be replaced on the car... Using air-pressure, or a length of hose to keep the valves closed when removing the springs...

    On some models, if the valve guide is machined for them, you can replace the "umbrella" seals, with Perfect Circle style seals, which are the premimum seals...

    The intake gaskets will act just like bad valve seals... They start to leak at the bottom edge of the port, in the lifter valley area

    What happens, the manifold sits across a 90deg 'V'.. after years of heating and cooling, that cause the manifold to "flex", the gaskets get very hard, and no longer seal...

    Replace with premium Fel-pro (the ones with the little orange silicone tracings around the ports), or factory gaskets ONLY>.. /forums/images/graemlins/cool.gif /forums/images/graemlins/truck.gif
     
  4. blasterD

    blasterD 1/2 ton status

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    Location:
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    In my experience, whitish blue smoke during acceleration can be attributed to bad rings. If you catch it early you can minimize the machine work it will take to get your engine back up to spec.
     

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