Hydraulic Lifter Preload Excessive?

Engine, Trans & Driveline

  1. lewtot184

    lewtot184 Well-Known Member

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    last time i checked those crane springs i got 108lbs@1.85", 260lbs@1.35". springs do vary some.
     
  2. EngineerDoug

    EngineerDoug Well-Known Member

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    Roger that - I have an adjustable pushrod checker on order to double-check my estimated length.
    Rough measurements appear below:

    Stock pushrod = 8.55"
    Lifter preload with 0.020" head gasket = 0.110"

    So if these figures are accurate - soon to be verified - I have a choice between an 8.450" and an 8.500" pushrod. Lifter preload will be either 0.060" or 0.060". Would you shoot for the low end or the high end of the preload range?

    Thanks!
     
  3. lewtot184

    lewtot184 Well-Known Member

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    with a stock set-up i wouldn't be afraid of .110". taking .010" out of that wouldn't hurt anything for sure. i just put a stock valvetrain/camshaft in one of my 440's and believe it or not the tappets aren't quiet at .070"-.080" preload.
     
  4. dvw

    dvw Well-Known Member

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    A couple things I see. First as long as the lifter piston doesn't bottom out in the lifter body, preload won't matter. Second, has anyone who commented on rocker scrub pattern ever done the math to see what the cage is when the shaft height is changed? I have, .060" makes a very small change in the overall scrub distance. I also agree that 105-110 on the seat is plenty. With all the flat tappet cam failures now a days I'd be leary to add too much spring pressure
    Doug
     
  5. EngineerDoug

    EngineerDoug Well-Known Member

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    Thanks for the guidance; I am returning the 911 springs today, and have the Crane 99839 springs on order. Once I get the heads mocked again I will use a checking pushrod and then I'll know where I have to go with the new pushrods.

    BTW I got real tired of using my overhead valve spring compressor, so I modified it per the photo below. Now I can use a ratchet instead of turning that infernal wheel. Soo much easier - I just welded a cheap socket onto the hand wheel.
    Valvespring_comp.JPG
     
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    • khryslerkid

      khryslerkid FBBO Gold Member FBBO Gold Member

      My Photo Garage
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