Hydraulic flat tappet lifters

Discussion in 'Street/strip 400/430/455' started by Jerrit72Riv, Oct 12, 2021.

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  1. Jim Weise

    Jim Weise EFI/DIS 482

    Mark,

    Yes, lifter bore clearance is an important factor in idle speed oil pressure when hot.. It's why two engines "built identically" will not have the same pressure..

    What weight and brand of oil are you using now? I find a lot of difference in room temp to hot viscosity drop off, depending on what oil your using.

    Most of my engines start up at 75-80 lbs, and then with the oil hot, will make that 75lbs at around 6000 rpm.

    JW
     
    Jim Weise, Oct 16, 2021
    #21
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    My engine starts up with about 70 psi, mostly because I do not use a choke. I feather the gas until it will idle on it's own, usually about 2 minutes. Then I drive it easy until the temperature comes up. While I am doing that, it's at 75 psi. On a hot summer day after an extended highway run, it usually idles around 22 psi at an in gear 750 RPM idle. At 60 MPH/2300 RPM on the highway, it's at 55 psi. Every time I have glanced at it going through the traps at around 5600 RPM, it's been between 75 and 80. I use Joe Gibbs HR-4, 10W/30 Synthetic.
     
    LARRY70GS, Oct 16, 2021
    #22
  3. Jim Nichols

    Jim Nichols Well-Known Member

    Cryogenic or DLC on lifters would be beneficial but expensive as it should be done on the cam also. Does anyone still nitride cranks? Maybe they could do cam and lifters too.
     
    Last edited: Oct 16, 2021
    Jim Nichols, Oct 16, 2021
    #23
  4. knucklebusted

    knucklebusted Well-Known Member

    That is a cool machine to regrind lifters. I just took mine to the recycler a month ago. I think they were too far gone. They showed tw0 different kinds of metal in the very concave cup. Some of then were at least 0.030 deep. Imagine how much you'd have to grind on that one to get it back convex!

    So, if you grind the lifters, cut the heads and block, you might be able to use the old pushrods! LOL
     
    knucklebusted, Oct 18, 2021
    #24
  5. Jim Weise

    Jim Weise EFI/DIS 482

    Jim Weise, Oct 19, 2021
    #25
  6. mikegs400

    mikegs400 Well-Known Member

    Jim what mach. shop do you use to resurface lifters?
     
    mikegs400, Sep 11, 2023
    #26
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