Oil pump shims

Discussion in 'Street/strip 400/430/455' started by Dragdoc, Apr 8, 2021.

  1. Dragdoc

    Dragdoc Well-Known Member

    My first experience with the BBB oil pump! I have the TA housing, iron pump plate, spring assortment, and am setting up the gear end play. Got myself the TA shim and gasket kit which says use a paper gasket and the appropriate plastic shim to allow .002-.003” end play. A straight edge against the gears fully seated freely allows .0015” under the housing base and .0020” with a slight drag. So .004 to .005” of gasket/shim.

    With the thinnest paper gasket on the alum housing base and a straight edge firmly across it (vertically...its rigid) over the gears I cannot get a .0030” under the straight edge but a .0025” freely passes under with no drag.

    Sooooo...how much does a paper gasket possibly compress? Should I be fine just using the thinnest paper gasket and no plastic shim? Thanks all
     
  2. LARRY70GS

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

    With the straight edge across the gear faces, and NO gasket, measure the distance between the bare gasket surface, and the straight edge. Add .002- .003 to that measurement and that is the thickness of the gasket + shim that you want. You want the smallest end clearance you can get without the pump binding. Experiment with thinner gaskets/shims.

    https://www.v8buick.com/index.php?threads/oil-pump-clearances-and-oil-pressure.326597/
     
  3. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    If you have difficulty measuring, you can start with a baseline gasket, assemble the pump, and see if it spins freely. If you binds, go up .001 each time until it moves freely.
     
    john.schaefer77 likes this.
  4. Dragdoc

    Dragdoc Well-Known Member

    No difficulty measuring!

    I have greater than .0015” and less than .0020” gear face (straight edge) to the timing cover base. I’m wondering what the paper gasket might compress to. Theoretically if the paper gasket does not compress from its stated .005” and I have .0015” worth of protruding gears then my clearance is .0035” which is too much. TA says use a paper gasket and add plastic as needed.

    I understand the idea of assembling and correctly torquing, then feel for binding. But couldn’t you end up with an unbinding .001” which is not within the preferred .002-.003”?

    Perhaps use a dial gauge and work backwards? Assemble with only the thin paper gasket and measure the movement of the gear shaft up and down?
     
  5. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

    I am pretty sure the chassis manual states .002-.006 end clearance is the target. So you likely are ok if you just use the paper gasket.
     
  6. LARRY70GS

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

    If it was possible to get a .001 clearance without binding, that would be preferred. The timing cover expands with heat, so the clearances increase. You want the minimum cold clearance. I think the gear faces may not be completely flat, and .001 would probably bind anyway.

    I think that would be a better way.
     
  7. 87GN_70GS

    87GN_70GS Well-Known Member

    I put my whole setup in the freezer overnight, then adjust end clearance to 0.001". So my clearance is good down to a 5 deg day :)
     
  8. Dragdoc

    Dragdoc Well-Known Member

    Anyone ever use only the mylar spacers and no paper gasket? Not sure how that might seal
     
    Mark Demko likes this.
  9. LARRY70GS

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

    Sure, should seal just fine.
     
  10. Smartin

    Smartin antiqueautomotiveservice.com Staff Member

  11. Mark Demko

    Mark Demko Well-Known Member

    I have many times, sealed fine.
    Even asked TA if this was ok, just using the shims with no paper gasket, Mike said "sure as long as its not leaking"
     

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