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Technical 427 Chevy tall deck problem?

Discussion in 'The Hokey Ass Message Board' started by Chevy Gasser, Mar 13, 2017.

  1. Chevy Gasser
    Joined: Jan 23, 2007
    Posts: 701

    Chevy Gasser
    Member

    I was getting ready to pull the engine out of a 65 series Chevy truck for a hot rod project. I drove the truck home a couple of miles. It didn't overheat and oil pressure was over 50 psi. It had a miss in it but since it hadn't been in service for years I pulled the plugs for a compression test. I found the #5 cylinder exhaust valve pushed all the way open and stuck there. I pulled the rocker arm off and tapped on the valve thinking it was just stuck open, the spring did not look broken. It did not try to return open at all, it just went down to coil bind, I was able to pry it up only a little but not back where it should be. The pushrod was not bent but was high and it did not tap down easy either. The lifter was pushed up and it would not go down or even try to follow the cam. I've never seen or heard of this. Anybody have any ideas what I can expect when I pull it apart?
     
  2. Jerrybigbird
    Joined: Oct 10, 2015
    Posts: 178

    Jerrybigbird
    Member
    from Montana

    Flat cam lobe and/or rust in the lifter bore is my guess
     
  3. VTjunk
    Joined: Jul 5, 2013
    Posts: 286

    VTjunk
    Member

    Yep. Seen one before, it was a tall deck too. Had a skip, after checking things out, pulled a valve cover, first thing I saw was a valve in the open position that shouldn't have been. Thought it was a guide issue at first.
     
  4. Jerrybigbird
    Joined: Oct 10, 2015
    Posts: 178

    Jerrybigbird
    Member
    from Montana

    Ive had em flatten out going down the road so ive never really siezed a lifter
     

  5. Sounds like the valve stuck open and the piston clinched it over like a nail. :eek: Might have broken the valve guide and possibly cracked the head. :eek: I hate to think what happened to the piston. o_O Might have even scrubbed the cam & lifter flat too. :( Check everything.

    Outside of that, you should be good to go. :rolleyes: Sorry. :(
     
  6. VTjunk
    Joined: Jul 5, 2013
    Posts: 286

    VTjunk
    Member

    Those low rpm engines don't have enough valve lift to hit anything
     
    Jerrybigbird likes this.
  7. Likely old stale gas or something caused the valve to sieze in the guide. and without the valve spring pressure to keep it riding on the cam the lifter bounced up above its normal travel and the varnish on the lifter near its base caused to stick also. Tap that lifter back down. Get a propane torch and heat on the valve guide and stem while squirting it with penetrating oil and it might come loose. Of course you will take the tension out of the valve spring. However its possible to change the spring without pulling the head.
     

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