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  • Valve Spring height

    I just got my heads back from the machine shop and need to put them together. The machinist there told me to check the installed spring height, and shim if necessary. I couldn't find anything in the shop manual for spring height, just the pressure/constant. I have new R2+ springs and want to make sure I take advantage of them.

    They are 570 heads with R3 intake valves and HD ex valves. All the valves are new and all seats were resurfaced.

    Anybody know the installed spring height?

    Dan Giblin
    Cincinnati, OH
    Dan Giblin
    Cincinnati, OH

  • #2
    2.031" is the standard measurement for Stude V8 heads. Surely the shop could have found that, unless maybe your new valves stem length differs from stock.
    It is the same dimension given for checking closed valve spring pressure which isn't listed in the shop manuals either.

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    • #3
      The machine shop should have done all that for you.

      Also, the machine shop should have an installed height micrometer. Checking with anything less is guessing to some degree of accuracy.

      FWIW, installed height is the place to start, but most important is seat pressure - R 2+ seat pressure should be 90#, 155# @ 1.75" and 185 @ 1.631".

      1. Use the valve spring micrometer to measure installed height.
      2. Use a valve spring tester to find the seat pressure at that measured height.
      3. If necessary, shim to the desired seat pressure.

      thnx, jack vines



      PackardV8
      PackardV8

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      • #4
        Remember to use the thickness of the damper spring seat when doing the measurements.

        Mike

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        • #5
          Thanks for the info. Heads went back to the shop today (they had the number). See I first ported them, then had the seats redone. Brought them home, CC'd the chambers, got them exact, then brought them back to be milled so I could dial in the C/R i wanted. Will my volume change if the installed spring height is too short? Will they need to cut the seat or the valve? Seems to me I went out of order on some steps. What is the typical way a performance valve job is done?

          Dan Giblin
          Cincinnati, OH
          Dan Giblin
          Cincinnati, OH

          Comment


          • #6
            Hi, Dan,

            As long as you have at least .075" before coil bind, too short (less than 2.031") is not usually a problem.

            Order of operations:

            1. Magnaflux for cracks and bake to remove carbon
            2. Pressure wash and dry.
            3. Shot blast, pressure wash again and dry
            4. Remove old guides and install new guides
            5. Run thread cleaning tap into all bolt holes
            6. Cut valve seats. Install hard exhaust seats.
            7. Bowl porting
            8. Match valves to guides, ream guides for specified clearance.
            9. Cut tops of guides for positive seals.
            10. Check valve installed height and valve spring seat pressure, adjust as necessary
            11. Mill head surface
            12. Pressure wash again and assemble
            13. Vacuum test for valve sealing
            14. Paint, spray lube on unpainted areas, bag, box, bill, ship.

            As you can see, it's a very labor and machine intensive process.

            thnx, jack vines


            PackardV8
            PackardV8

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