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Technical Sbc283 valve lash question

Discussion in 'The Hokey Ass Message Board' started by olds vroom, Jun 26, 2020.

  1. olds vroom
    Joined: Jan 29, 2010
    Posts: 924

    olds vroom
    Member

    I’m working on a 64 sbc 283 in a 64 Malibu . The engine was recently rebuilt to stock buy a local garage less than 1000 miles ago and just broke a rocker stud off . I’ve replaced the stud but noticed all the rockers are really tight, no play at all in any position. Shouldn’t there be at least a little play in them ? I can’t find a spec for gapping for between the rocker and valve springs any help would be appreciated.


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  2. wheeltramp brian
    Joined: Jun 11, 2010
    Posts: 947

    wheeltramp brian
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    There should be no gap if it has a hydraulic cam .if solid then yes there should be a gap.any specs on the motor?
     
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  3. ROADSTER1927
    Joined: Feb 14, 2009
    Posts: 2,740

    ROADSTER1927
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    Hydraulic lifters no gap.
     
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  4. olds vroom
    Joined: Jan 29, 2010
    Posts: 924

    olds vroom
    Member

    It’s a 1964 stock sbc 283 with a 2 Barrel Rochester carb the only upgrade is hardened valve seats.


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  5. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,034

    Ebbsspeed
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    Here's one video out of about 10,000 that shows one way to do it. If it is a stock setup they are zero lash hydraulic lifters, so there shouldn't be any looseness in the rockers.
     
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  6. olds vroom
    Joined: Jan 29, 2010
    Posts: 924

    olds vroom
    Member

    I pretty sure they are hydraulic lifters but what is the gap if they are solid?


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  7. squirrel
    Joined: Sep 23, 2004
    Posts: 46,101

    squirrel
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    We'd have to know what cam it has to tell you the lash if it's a solid lifter cam. 99.8% of 283s have hydraulic lifters in them. If the rest are all at zero lash, it's very very unlikely that it's a solid lifter cam.
     
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  8. If it has a hydraulic cam they won't have any play even on the heel of the cam (where they are adjust initially). I adjust them to no play and half a turn the book will tell you way more preload than that.
     
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  9. olds vroom
    Joined: Jan 29, 2010
    Posts: 924

    olds vroom
    Member

    Thanks you all have been very helpful . I woke up at 4:30 this morning and thought there should be more play in those rockers so this puts me at ease .


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  10. Hydraulic lifters, when working properly and with sufficient oil pressure, should run at zero lash. Even with the engine turned off they should hold zero lash. Except when they don't.

    With the engine shut down and not making oil pressure to keep the lifters pumped up, there's always a few valves being held in the open position. The pressure of the valve springs then attempts to make the lifters "bleed down" and can result in greater-than-zero valve lash. But it may be a matter of hours, days, weeks or even months before this condition occurs, depending on the condition of the lifters, cleanliness of the oil and valve spring pressures. And usually any vale lash noise will go away shortly after the engine is restarted and oil pressure begins to build.
     
  11. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,034

    Ebbsspeed
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    Just to add a bit of info, if it was a solid lifter setup and there was no looseness in the rockers it wouldn't run very well for very long. You'd have some burned valves and be down on compression.
     
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  12. olds vroom
    Joined: Jan 29, 2010
    Posts: 924

    olds vroom
    Member

    I just took it around the block all is well again thanks for the help .[​IMG]


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  13. squirrel
    Joined: Sep 23, 2004
    Posts: 46,101

    squirrel
    Member

    thanks for the report back!
     

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