No announcement yet.

Lapping compound in prop installation

  • Filter
  • Time
  • Show
Clear All
new posts

  • Lapping compound in prop installation

    Anybody here with experience lapping a propshaft taper/prop have an opinion on "coarse" versus "fine" compound? My 94 Mastercraft owner's manual says use "coarse." The linked to source says use "fine." Neither gives a numerical grit rating, but I'm considering Loctite Clover compound. Their "coarse" is 120 grit. Their "fine" is 280 grit.
    1994 ProStar 190, 350 TBI, 1:1, ACME 541, PTM Edge VR-140

  • #2
    Is this even necessary? Might call Eric at OJ props on it.

    Making boomers great again!! Boomin'


    • #3
      I use Permatex water-based Valve grinding compound from Napa. From the description: "Can be used for lapping and grinding chromium-cobalt, hard-faced seats and discs. Removes burrs, surface defects, gums, carbon deposits and corrosion. Mixes with water to form easy-to-use paste. Combines special grits of various sizes that become finer as the compound is worked. Provides a fine, smooth finish" This was my only local option and worked well. To grind faster, wipe and re-apply to keep a course grit going. Once I had the contact I wanted I finshed smoother by working compound longer.

      I skipped the Prussian Blue at the advise of a local engine builder and used a sharpie. Amazing how little contact area there was before lapping verses after.


      • #4
        Originally posted by d2jp View Post
        I use Permatex water-based Valve grinding compound from Napa.
        same here, works great.