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Technical Things you find in a flathead

Discussion in 'The Hokey Ass Message Board' started by 46international, Oct 1, 2025 at 6:36 AM.

  1. A few years ago I picked up an 8BA motor and just last week I started taking it apart to see what I got. When I removed the crank I took it out with the flywheel attached only removing it when I started cleaning it. After taking the flywheel bolts out I saw two lock washers between the crank flange and the flywheel. One lock washer installed over each dowel in the crank flange. I also notice that one of the bolts that holds on the cover for the oil pump drive gear was being rubbed by the flywheel.
    Now, I know that flywheel could bot have been running true with those washers in there and my question is, WHY? I did not notice the flywheel wobbling when spinning the crank over while taking it apart, but I bet it did.
    Why would someone space the flywheel back 1/8"? Could there be some type of mix up with parts from different engines? Crank that does not "go" with this flywheel or block? I thought all the cranks were the same, are there different flywheels? This thing had a 3 speed trans attached and it looked all stock. (but who knows) Could the flywheel have been moved back so the pilot bearing would reach the trans input shaft? What about starter? could this have been done so the starter would mesh?
    any thoughts?
     
  2. RMR&C
    Joined: Dec 26, 2009
    Posts: 4,869

    RMR&C
    Member
    from NW Montana

    If you put a 59ab flywheel(or earlier) on an 8ba it hits the back of the block enough that it won't turn. Likely the reason. Sounds like a farmer fix.
    Post a pic of the flywheel if you still have it
     
  3. Thanks RMR&C, I never knew that. I do still have the flywheel and I have another one that came off of another 8BA so I can compare after I dig it up. I guess moving the flywheel back some put the ring gear in the correct position also. I'll have to check the other one.
     
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  4. What about the ring gears? do they interchange between the 59A flywheels and the 8AB flywheels? I think the 2nd 8AB flywheel I have has a bad ring gear but like I said I'll have to find it and take a look.
     
  5. Andy
    Joined: Nov 17, 2002
    Posts: 5,375

    Andy
    Member

    The ring gears are different. Early narrow, later wider
     
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  6. 51504bat
    Joined: May 22, 2010
    Posts: 5,553

    51504bat
    ALLIANCE MEMBER

    A while ago I bought an 8ba that was supposedly stuck. Turns out it wasn't so I figured what the hell I'll see if it fires. It had a truck pan on it so I pulled the cover to check the pump screen and a dead mouse came out with the oil. Cleaned the screen, added some new oil, and a set of used plugs ant it fired and actually had decent oil pressure when started.
     
  7. Mac VP
    Joined: May 13, 2014
    Posts: 508

    Mac VP
    Member

    The 49-53 flywheel bolt holes for the pressure plate were drilled all the way through the flywheel….you can easily see the holes from both sides. The 1941-48 flywheels were a bit thicker and the bolt holes were blind….only seen from the clutch side. These two types of flywheel are NOT interchangeable as the ring gear location will be off.
     
    46international likes this.
  8. lostn51
    Joined: Jan 24, 2008
    Posts: 3,105

    lostn51
    ALLIANCE MEMBER
    from Tennessee

    Talking about finding stuff in a flathead, when we were rebuilding our 8BA I read an article in Street Rodder that they still had a lot of the casting sand in them. So I got a 1/8” filler rod and started jabbing it into the water ports and there was quite a bit of sand coming out. I spent an afternoon cleaning the sand out of it the best that I could and this motor has been running nice and cool since
     
  9. Another 8BA motor I got had a dead mouse in the lifter valley but no way that one was going to ever run....It's now a table base at my son's house.
    Speaking of mice, back in the mid 80's my cousin got ahold of a 49 F1 that belonged to our grandfather, he got it running and drove it to my house about 30 miles away. He got pulled over for making too much smoke. The mice had built a nest in the lifter valley and clogged it up so bad the oil could not drain back down I guess the excess oil got sucked up past the valve stems.
     
    51504bat likes this.

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