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Engine rebuilding

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  • Engine rebuilding

    Many Model A owners will need their engine overhauled at some point. There are great many questions that come up when this occurs. We strongly encourage owners to do careful research, as there seems to be a lot of shops that claim they know engine building, but few that really do. Questions such as, babbitt or inserts, ring gaps, piston-to-cyl wall clearance, piston choices, camshaft choices, proper cleaning of the water jacket, valve clearances (lash), bearing clearances, and such need to be addressed. Word of mouth from the pros on this board will usually steer you right. Several of us have extensive engine building experience and would be happy to entertain questions and suggestions. It is important to note that in many respects, engine building is not something you want to skimp on. Clearly owners are looking for reliability and longevity. We can help you find that. But, of course, you get what you pay for.

    We recently knew of a guy who bought a "freshly rebuilt motor" from a third party, "for a good price", and his complaint was, "I can't turn it over with the crank" RUN away, do not buy that motor. It has been built WRONG. Once he got it running, it quickly locked up, having spun the rear main bearing. I have seen line-boring done off-center. I have seen timing gears beat to hell because of improper assembly. I have seen piston-to-wall clearance done very wrong. The list is endless.

    Be aware that any engine, and particularly the Model A engine, has peculiarities that MUST be taken into account for a proper build. For example, in most Model As, cylinders 3 and 4 run 10-20° hotter than 1 and 2. Your IR temp gun tells you so. As soon as the water returning from the radiator enters the block via the inlet on the driver's side of the block, between cyls 2 & 3, it is immediately sucked forward by the water pump. Little cooled water is left to circulate around the water jackets of 3 and 4. If this is not taken into account, you can have major problems. Those that are used to building a Chevy or Ford modern small block, for example, will be out in left field on an A motor.

    Engine overheats can lead to shrunk (collapsed) pistons, a topic for another time, but we have seen it many times. In the meantime, make sure your newly rebuilt engine is timed properly, and had the water jacket properly cleaned during rebuilding, and get yourself a good radiator.
    Last edited by tbirdtbird; 05-01-2017, 11:03 PM.

  • #2
    My engine has had some overheats, and it has a slight ticking near the #3 cylinder. I'm pretty sure it's from an overheat collapsing a piston skirt. As soon as I get my oil pan painted, I can installed the other rebuilt engine I have.
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    • #3
      I think some engine rebuilders set number 3 and 4 to tight. I have seen a few engines with 3,4 scored.


      • #4
        I agree, George. At this point I am setting 1,2, and 3 at .0035-.004, and #4 to .0045-.005
        Have never had piston slap. Those pistons heat up and expand quickly......
        A motor is a living thing when running; not just a static pile of parts.

        we have a pile of scored pistons here from motors set up too tight.
        Henry's spec of .002 doesn't cut it. He was dealing with a split skirt, also.
        And a supplier of modern pistons has no clue about the peculiarities of an A motor, so we ignore their recommendations


        • #5
          Rich Fallucca has a very good video on You Tube about how they rebuild a Model A engine. Good information.


          • #6
            Originally posted by Captndan View Post
            Rich Fallucca has a very good video on You Tube about how they rebuild a Model A engine. Good information.
            here is the link:::

            3~ Tudor's & 1~ Coupe
            Henry Ford said,
            "It's all nuts and bolts"
            "Start by doing what's necessary; then do what's possible; and suddenly you are doing the impossible."

            Mitch's Auto Service ctr


            • #7
              had my 1930 tudor eng rebuilt by dreamworks james rogers in Ashville nc he did a great job runs like new
              1930 tudor
              1923 model t roadster r/u


              • Beauford
                Beauford commented
                Editing a comment
                I as well used James. He did a great job and is free for advice anytime I need some.....most folks after the check is cashed don't want to bother with you anymore.

            • #8
              Some one needs to come up with a pump that would go in the water inlet. That would pump the water to the back off the block. That would cool 3 and 4 better, plus it would help keep the back of the block water jacket clean.


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              • George Miller
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