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Technical Full Floating Rod Bearings

Discussion in 'The Hokey Ass Message Board' started by Ldjr003, May 8, 2020.

  1. Ldjr003
    Joined: May 8, 2019
    Posts: 20

    Ldjr003

    What is the advantage/dissadvantage to using full floating rod bearings on a 49 to 53 Flathead V8. Will be running a Mercury 4 inch crank.
     
  2. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,005

    dreracecar
    Member
    from so-cal

    Big end (crank) or small (pin)end???
     
  3. RichFox
    Joined: Dec 3, 2006
    Posts: 9,931

    RichFox
    ALLIANCE MEMBER

    At least you don't have to worry about spinning a bearing
     
    jimmy six, Hnstray and egads like this.
  4. sliceddeuce
    Joined: Aug 15, 2017
    Posts: 2,982

    sliceddeuce
    Member

    Hard to argue that point Rich.
     
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  5. alchemy
    Joined: Sep 27, 2002
    Posts: 15,520

    alchemy
    ALLIANCE MEMBER

    Advantage: half the bearing speed on each surface.

    Disadvantage: cost more and harder to install correctly.
     
  6. AngleDrive
    Joined: Mar 9, 2006
    Posts: 771

    AngleDrive
    ALLIANCE MEMBER
    from Florida

    In order to use floating bearings crank needs to be reground smaller and offset for a 4 1/8th stroke.
     
  7. Ldjr003
    Joined: May 8, 2019
    Posts: 20

    Ldjr003

    Stock 4 inch Mercury crank, not a 4 and 1/8th.
     
  8. AngleDrive
    Joined: Mar 9, 2006
    Posts: 771

    AngleDrive
    ALLIANCE MEMBER
    from Florida

    I know but the full floating bearings won't fit 'your' crank journal.
     
  9. Ldjr003
    Joined: May 8, 2019
    Posts: 20

    Ldjr003

    They are on the crankshaft now. I dont understand what you're saying. They are 030" under rod bearings on an 0 30" crank.
     
  10. AngleDrive
    Joined: Mar 9, 2006
    Posts: 771

    AngleDrive
    ALLIANCE MEMBER
    from Florida

    Sorry, your right, I was thinking of the early 39 to 42 bearings used for a stroker crank.
     
  11. 42merc
    Joined: Dec 19, 2010
    Posts: 701

    42merc
    Member

    The floaters will work with the Mercury crank. But,you must use '46-'48 Ford rods that are machined for the full floating bearings.
     
  12. 19Fordy
    Joined: May 17, 2003
    Posts: 6,815

    19Fordy
    Member

    kidcampbell71 and Jet96 like this.
  13. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,223

    56sedandelivery
    ALLIANCE MEMBER

    Learned something new today, well actually two times today. Never heard of full floating crank bearings, or at least in "normal" cars/trucks; piston pins yes. I know some motorcycles, and some high end European cars, use roller/sleeve bearings, but those cranks have to be disassembled/assemble to do the bearings. The other thing today, why in the h*ll did Ford come up with a negative post battery clamp that tightens/loosens with a "slide" and opposed "wedge" tighteners. You know what I'm talking about, if you know what I'm talking about; if you don't, head to a wrecking yard an see for yourself. The negative battery cable is apparently part of an entire harness that has to be swapped out. And this was all because of a body shop that busted the negative battery post loose trying to remove the cable clamp; it's been almost 3 years, so not much I could probably get them to do. This is a nationwide firm that sounds like they should be making baby food. I took it all apart, clean it up, drilled a couple of holes, added a bolt and nut (like it should be, like the positive post is), and now it's actually serviceable. I am Butch/56sedandelivery.
     
  14. Ldjr003
    Joined: May 8, 2019
    Posts: 20

    Ldjr003

    what ?????
     
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  15. Ldjr003
    Joined: May 8, 2019
    Posts: 20

    Ldjr003

     
  16. Ldjr003
    Joined: May 8, 2019
    Posts: 20

    Ldjr003

    My friend, these are full floating ROD Bearings, not crankshaft bearings. Just a little FYI.
     
  17. Ldjr003
    Joined: May 8, 2019
    Posts: 20

    Ldjr003

    No big deal, thanks for your fast response. '49 Ford F1, Ford AOD Trans, Ford 8.8 Posi Rear.
     
  18. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,471

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    I think the misunderstanding is yours. The question was which end of the rod was being discussed, the crankshaft (end) or the (piston) pin end?
     
  19. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,005

    dreracecar
    Member
    from so-cal

    Sorry about my ignorance in this matter, The connecting rod that goes between the crank and piston to my knowlege pivots at each end, the piston side has a pin that is either pressed into the rod and floats in the pin bore OR the pin is fitted on both rod and piston held in place by retainers--- hence the term "full floating" . The crankshaft end of the rod is clearenced for oil both on the circumfrance and side and that allows the rod to automaticly float on the crank journal, so what extra "float" do you need if you dont mind me asking?
    Rods have bearings for the crank side and some applications they "BUSH" the pin side because there is no 360* rotation to keep a bearing from pounding out
     
    Last edited: May 9, 2020
  20. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,223

    56sedandelivery
    ALLIANCE MEMBER

    Main bearing, rod bearings, it really does't matter, you're not going to see it on an American made automotive engine. They tend to be "smaller" engines, like motorcycles, with cranks that "come apart" to install/remove the bearings. I think you know what I meant anyways. Here's your knife back. I am Butch/56sedandelivery.
     
  21. dan c
    Joined: Jan 30, 2012
    Posts: 2,093

    dan c
    Member

    '46-'48 bearings work on a '49-'53 crank, but not vice-versa. oil holes...
     
  22. Budget36
    Joined: Nov 29, 2014
    Posts: 3,467

    Budget36
    Member

    I tore apart a 59A that had them on the crank, someday I'll pull the pistons off the rod to see, but I don't think floaters were used on the small end, were they?

    I'll go look through Bruce's reply.
     
  23. saltracer219
    Joined: Sep 23, 2006
    Posts: 750

    saltracer219
    Member

    46-8 Ford Flatheads had a common bearing shell that both rods on a crank pin pivoted on the O.D. of the shell. The bearing was not locked in the rod and was pressure oiled on both the O.D. and the I.D.
     
    warbird1 likes this.
  24. alchemy
    Joined: Sep 27, 2002
    Posts: 15,520

    alchemy
    ALLIANCE MEMBER

    All flathead Ford rods had a brass bushing pressed into the small end. No "bearings" up there.
     
    Desoto291Hemi and Budget36 like this.
  25. Boat engines use roller and ball bearings on the crank and rods
     
  26. Ldjr003
    Joined: May 8, 2019
    Posts: 20

    Ldjr003

    No I believe the mistake is yours. Show me a Flathead that had bearings in the small end of the crank. There's such a thing as full floating wrist pins, but bearings......No
     
  27. Ldjr003
    Joined: May 8, 2019
    Posts: 20

    Ldjr003

    My bad,I meant small end of the rod.
     
  28. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,471

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Not my error, I never made any claims as to bearings per se, only pointing out that it appears you misunderstood what the other fellow was asking. I can readily admit my mistakes, and have here and elsewhere.....can or do you?
     
    Budget36 likes this.
  29. Ldjr003
    Joined: May 8, 2019
    Posts: 20

    Ldjr003

    You need to go back and read again !!! And then tell me about bearings of any kind, on the small end of a connecting rod.
     
  30. rusty valley
    Joined: Oct 25, 2014
    Posts: 1,520

    rusty valley
    Member

    i have a set of rods out of my 59ab as i used the merc rods that came with the crank. cheap if you need em
     

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