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line boring Model A block, with pictures.

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  • line boring Model A block, with pictures.


  • #2
    The angle has a bearing that is mounted with springs. It just steadys the bar so it does not vibrate. If you mount it solid you can force the bar out of line, which would make crankshaft bind.

    First picture shows the plate with bearing that locates off the camshaft and pan rail.

    The picture below the first picture shows the support bearing held in place by the factory machined cap and block.

    You would only get in trouble if some one machined the pan rail. or messed with the block and cap. I always check those two things.

    The same picture shows the tool for counter boring for the thrust bearing.


    • #3
      1 the way the front plate is made it has a pilot that goes in the cam bore, and a tab lays on the pan rail. so you always have the right distance.

      2 There is two screws in the boring bar, one tightens the tool, the other to adjust it. I put a indictor on the end of the tool then adjust what ever I need.

      3 To check the bore size is a little difficult lucky I did this kind of work for ever. I use spring calipers, then mike over them. I would not recommend this as it takes a lot of practice to develop the feel.


      • #4
        Since I can definitely see an advantage to boring this way, the need to only bore about 3 inches distance, I am also wondering what supports the total length of the bar? Is it that plate in the middle?

        Since you are boring for inserts, do you just have a fixed diameter and since it looks like you are using carbide tools, do you need to sharpen the tooling at all boring out the soft cast iron? If so, do you have a gauge or something setup for refitting of the tools?

        I definitely like the setup, kinda simple, with the caps off, drop the bar assembly into the journals, affix the caps and bore. I know that is simplified a lot, since you still need to index off the faces and make sure everything is parallel, but that is great.

        THANKS for sharing George.
        You wana look waaay far up da road and plan yer route because the brakes are far more of a suggestion than a command!


        • George Miller
          George Miller commented
          Editing a comment
          The bar is supported on both ends by bronze bearings. The one in the center only stops the vibration. If you put a solid bearing in the middle you could cause it to bore the center out of line. With two bearings you do not have that worry. You do have to make sure you have no runout on the od of the bar.

          The tools are good for a couple of jobs. I bore the bearings in two passes a rough and a finish pass. I adjust the cuter with a indicator. No gauge

      • #5
        I know the engine is very dirty, but I always clean them when I get all the machine work done. That way there is no metal chips and such left in the engine.If I knew It was going to be viewed by so many I would have cleaned it some before.

        This was one of the engines that went through a flood it still had water in it when I took it apart, and the oil pan was full of mud.


        • #6
          Does not matter George your effort is appreciated always time to make it pretty, I assume you already checked it for cracks etc. I assume you are putting in inserts as well.


          • George Miller
            George Miller commented
            Editing a comment
            Yes inserts I just tried some in there they fit nice. No cracks, the guy had 6 engines. 4 were cracked on the driver side. It does have a sleeve, probably had a wrist pin come loose from those old center lock pistons. The sleeve was put in like they use to do it with out a stop.
            Last edited by George Miller; 12-20-2017, 03:48 PM.

          • Dennis
            Dennis commented
            Editing a comment
            George, did it have a lip at the top or can you tell. All of the diesels with wet sleeves I worked on in the past had a lip at the top. I actually saw a couple of those snap the top of the sleeve at the radius of that lip.

          • George Miller
            George Miller commented
            Editing a comment
            No lip and the bottom of the sleeve is hanging below the cylinder about 1/8 inch.

        • #7
          George, thanks for the great photos and info.

          I've always wondered, during the line boring process, what steps were taken to make sure the crankshaft flange will be perpendicular to the flange that the flywheel housing mounts to?


          • George Miller
            George Miller commented
            Editing a comment
            I have worked on some engines the crank was not centered like it should be. Some of the boring bars located off some one else work. That was not a good thing.

            When I made this rig I was only going to use it for the A. So made it so it would just drop in place.
            Last edited by George Miller; 12-21-2017, 11:24 AM.

        • #8
          When I made this rig used what I had. The bar is a scrap tie rod from a hyd cylinder we manufactured at work. We made them to 24" bore. We made the 8 hyd cylinders for the movie Tintanic they were 8 inch bore 255 inch long stroke. They used them to make the ship look like it broke in to.


          • #9
            If you ever stop in Nebraska you can give me some tutoring on setting up my Kwikway to cut the blocks for inserts. I have tried a few times, but did not feel comfortable with the results as compared to the cam. Don't want to mess up my numbers matching block or a standard bore diamond block. I have a junk block that I may try to this spring. Rod
            "Much of the social history of the Western world, over the past three decades, has been a history of replacing what worked with what sounded good." Thomas Sowell


            • #10
              Do you have the distance from the cam to the crank, if not I have it here some where.


              • George Miller
                George Miller commented
                Editing a comment
                It is very important to get the crank on dead center where it was originally. If not you are going to have all kinds of problems. transmission shaft will be at a angle. piston rods will be walking on the wrist pins, pistons can twist while they go up and down. cam gear will not have the right lash, The engine will be noisy and not last as long as it should. I never want to trust the one before me. If I buy a carb at the junk yard I get the greasy dirty one, because I know it was working and no one has worked on it.

            • #11
              I lined bored loader buckets,the datum wasn't critical,looks like your first bearing is god,by picking up both pan rail and cam bore as reference your spot,on bet it took a few hours to knock that tool out..the others are to hold alignment...what we don't see is the master machinist skills involved,things like feed speed and correct tool sharpening..measuring the bore accurately and quickly with the bar in place,stuff the layman doesn't realize till the he's faced with doing it. Setup with patience and precision,once the process is going it looks like he's just goofing off,watching the work..the machinist earns that right..Ill come clean blocks for you,hell,I'll spitshine the shop if you cut the one I have that needs done..


              • #12
                machined the notches in for the inserts today, forgot to take pictures, but we have one more engine to do. Will try to remember to take some then. Used a woodruff cutter.


                • #13
                  Here is a photo of some Model A line boring lineup fixtures. The left one is a Kwik Way LBM good for A's, B's, V8's and tractors, the center one I don't know which line boring machine it is for but I use it as a double check of my LBM and the RH one is for a Tobin Arp with a 1.25 bar.



                  • BNCHIEF
                    BNCHIEF commented
                    Editing a comment
                    Did not know you did that work.

                  • Grover
                    Grover commented
                    Editing a comment
                    Yep, sure do, but I do babbitt, no inserts. I like to drive Model A's as they were built. LOL

                    Did machine one block to install cam bearings. That was fun.

                  • BNCHIEF
                    BNCHIEF commented
                    Editing a comment
                    Maybe sometime Al and I can come and see you and I could hear some great stories.

                  • Grover
                    Grover commented
                    Editing a comment
                    Sounds good.

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