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350 rocker studs loose

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bushwacker, Sep 12, 2000.

  1. bushwacker

    bushwacker Registered Member

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    If it ain't one thing its another! Just finished replacing two press fit rocker arm studs with screw in type, buttoned it up ,adjusted all the valves and ran it for about an hour, real smooth.Then kapow! Another pulled loose. Anyone had a similar experience? Engine only has approx. 40k since last major o'haul.I'm worried that this might continue on a random basis.
     
  2. turbo

    turbo 1/2 ton status

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    Been there done that.

    After I pulled the heads I found the underlying prob.

    Burnt exhaust seats (not designed for unleaded fuel) letting exhaust valve pull up into head and wedge there.
    Then when cam pushes push rod and rocker gets a shove valve won't budge down so the stud pulls up.
    Hey somthing gotta give.

    The real kicker is since the exhaust valve is stuck closed the compression checks out OK.

    You need to rebiuld or replace the heads with ones with hardened seats designed to live with no lead gas.

    It sucks don't it.

    Mine was a M code 86000 GVW 350 from an 82 designed to run with no cat on leaded gas.
     
  3. bushwacker

    bushwacker Registered Member

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    Turbo, thnx for the info, I had hardened seats installed on the last rebuild. If it makes any difference, all three that loosened were intake valve rocker studs, and all were on the right bank. Was hoping to not have to pull the heads.But, I'm gonna stay after it until it's right.
     
  4. Smitty

    Smitty 1/2 ton status

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    Did you install stronger valve springs when you had the valve work done? I've had to install threaded studs on smallblocks because of the higher spring rates of some of the aftermarket kits.
     
  5. Emmettology 101

    Emmettology 101 3/4 ton status

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    Are all your pushrods correct length? Maybe some got screwed up and you got a few longer ones.

    Just a thought.

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; http://emmett.coloradok5.com
     

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