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problem with spinning the rear bearing. I found a cure.

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  • problem with spinning the rear bearing. I found a cure.

    To fix the problem take the rear upper insert and cut a groove from the front of the oil well on the pass side to back of the well on the driver side. This will give you a hydraulic wedge effect to put oil under the rear main between the shaft and insert. Make sure you do not go beyond the rear oil well, or you will have rear main leak. It is important to put the well from the pass side to the driver side, because of the way the crank turns. It helps the wedge effect.

    The problem is it is way to far for the oil to travel from the front of the bearing to the rear. The bearing is 3 inches long. I know this works because I have been doing it this way for some time. If you do not want to do it this way, you will have to leave more clearance, which I do not want to do. I like the .001 per inch rule.The rule has worked for me for 60 years. Now if you have pressure oiling you will not need to do this.
    Last edited by George Miller; 06-04-2017, 05:52 PM. Reason: add a word

  • #2
    George, let me get this right. The groove you are cutting is on the back (outer side) of the insert between the insert and the block? This would obviously not go clear through the insert, but be deep enough to "trap" the oil and create a suction type oil to block friction?
    You wana look waaay far up da road and plan yer route because the brakes are far more of a suggestion than a command!


    • #3
      No the groove is between the crankshaft and bearing. on the side that the bearing material is on.
      Attached Files
      Last edited by George Miller; 06-05-2017, 11:27 AM.


      • #4
        Hmmm, ok.
        You wana look waaay far up da road and plan yer route because the brakes are far more of a suggestion than a command!


        • #5
          George, can you post a pic? Even on a shell that is NG



          • #6
            I will check and see if I got one, if not maybe I can find a spare shell and make one. A picture would explain it better.


            • #7
              I can not get the picture to load. I could E mail it maybe. I did find one.


              • #8
                George email it to me [email protected]
                3 ~ Tudor's
                Henry Ford said
                "It's all nuts and bolts"

                Mitch's Auto Service ctr


                • #9
                  A friend decked the bottom of a 427 Ford, cut the main caps & align bored the block.-----"Bill, I spent 3 hours fitting the center main, it kept seizing, what do you think the cure was"?-----"The knotches in the block for the insert tabs were TOO shallow"----"How in hell did you know"???------"I'm a GENIUS"!!--LOL
                  Bill Luckyguess


                  • #10
                    I would not say it was a lucky guess. I think you analyzed it. You worked on cars for a living, you must know what you are doing.You also have a son that knows what he is doing. I think it is in the genes.


                    • #11
                      Originally posted by George Miller View Post
                      I would not say it was a lucky guess. I think you analyzed it. You worked on cars for a living, you must know what you are doing.You also have a son that knows what he is doing. I think it is in the genes.
                      Yes, my "SON" Mitch knows his S**T! My real SON, Gregg (RIP!) knew his S**T, also. It all goes back to Chief, my Dad, who instilled car stuff in us. He was a GENIUS fixer & added "humor" to help us remember stuff.
                      Chief HATED Model Ts, but had a DEEP love of Model As. Chief spent all his spare time, building dependable Model As to sell, (Under a HUGE Oak Tree, with a Chain Hoist!), so we could EAT WELL!
                      The tree could park 6 cars, easily! I could write PAGES & PAGES about our escapades, & BORE you to DEATH--LOL
                      I gotta' go feed my Dog!
                      Bill Blessed


                      • #12
                        I have a connecting rod from a Top Fuel Dragster. It uses a dowel pin in the rod cap, to prevent spinning. I wonder if they use them on the MAINS???
                        Bill W.


                        • #13
                          I have a couple of times. I used a step dowel pins which were smaller where it went into the bearing, and bigger where it went into the block.. That way it could not work its way out. I used them on my hill climb engines that turn 5,000 rpms. worked real good.


                          • #14
                            Here is the pic from George showing the insert shell. The top pic shows the bearing with the groove, and the bottom one is highlighted to show where it goes..

                            Sorry George i just found this pic you sent me in my spam folder from Monday

                            Last edited by Mitch; 06-10-2017, 08:55 AM.
                            3 ~ Tudor's
                            Henry Ford said
                            "It's all nuts and bolts"

                            Mitch's Auto Service ctr


                            • #15
                              I also have some info on AER inserts pasted on my website
                              I put this together after talking to Rich.
                              I was confused about the proper bearing sizes for my Burlington crank.
                              The Burlington is machined to the original Ford dimensions, which are not standard in industry lingo.

                              You might expect the Burlington to use 'standard' Model A size inserts, but you would be wrong.
                              The Burlington and NOS Ford use the -0.002 size.
                              A NOS Model B crankshaft would use 'standard' size, but not a Model A.


                              Here are a couple of screenshots. Go to the URL link above to get the whole page and story and info from Rich.


                              • #16
                                Here is a dog's breakfast of caps I have taken out of engines I torn down over the years.
                                Note the lack of tinning, hand cut grooves, wrong helix groove, etc.

                                George has the right idea.
                                Use inserts unless you happen to know where to get quality babbitt work.


                                • #17
                                  Here is a copy of the Ford block drawing, showing the proper orientation of the grooves in the block.
                                  This view is not through the block.
                                  It is just like looking at the block sitting upside down on your workbench.

                                  Note the rear block groove helix is the opposite orientation of the front and center main groove helixes.

                                  This is to help keep the oil in the engine rather than getting forced out the front and rear during crankshaft rotation due to hydrodynamic forces.

                                  The caps have the opposite helix because the oil is supplied from the block at the top, routed to the extreme ends of the block, fills the well, and then the hydrodynamic forces pull the oil in the caps inward, away from the ends and leakage during crankshaft rotation.

                                  Rear main bearings have opposite helix from the front and center bearings, both in the block, and in the caps.

                                  Shown above is the proper way to groove the block rear main bearing insert shell, as George showed earlier, if you are inclined to do so.
                                  Only the upper shell would benefit IMO, not the cap.


                                  • #18
                                    agree just the shell in the block. Doing the cap would take away bearing surface where the real load is. Plus the crank would already be riding on the oil.


                                    • #19
                                      Here is an interesting front and center main cap.
                                      It has a milled groove in the steel cap, behind where the groove is to be cut in the babbitt.
                                      I don't know how common this is, but it is the only one I think I have.

                                      Also on this cap, there is no trace of tinning under the babbitt, but just a little on the ends.


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