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Thread: Cj2a frame vs cj3a frame

  1. #1
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    Cj2a frame vs cj3a frame

    In my research, i have concluded the frames of the cj2a and cj3a are the same and can be interchanged.

    Can someone with more expertise confirm this.

  2. #2
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    There is a difference with the left front, around the fuel pump. Engine mount horn. It is how I determined I have a CJ2A body on a CJ3A frame.

    https://cj3a.info/cj3a/cj2acj3a.html
    Last edited by 51 CJ3; 11-18-2021 at 07:46 AM.
    Jeff
    '51 CJ3A
    '47 CJ2A

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    It can be made to work if you want to swap tubs. I chose to make mine match a CJ3A since that is what the frame is. I could keep it a CJ2A or make it military but prefer to return it to it’s original (more or less) configuration.
    Jeff
    '51 CJ3A
    '47 CJ2A

  4. #4
    Super Moderator bmorgil's Avatar
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    The main difference is the location of the left front motor mount. The 3A requires a different front motor plate to match the location of the relocated left front motor mount. There was more than one 3A built on a 2A frame, and quite a few motors swapped between the two. A motor mount adapter was cast by the Willys factory to allow the use of the 2A motor in a 3A frame. Some early 3A's had a 2A motor in them with an adapter, as Willys used excess inventory in the lean times.

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    This thread is very revealing to me. WOW Someone in my projects deep past fabricated a sort of adapter to allow the motor to fit like a CJ-2A. My frame looks like the illustration from the 51CJ3 post. Does anyone know if any of those WILLYS adapter castings still exist? With mine, someone used a piece of rectangular steel tube that bolts to the left front mount and then to the engine. It certainly works fine but just not beautiful!
    Seems what I have is a 2A on a 3A frame. I also have a 3a windshield frame. All of my S/N tags are CJ2-A.

    This forum is incredible. I have been running around the shop trying to figure out what happened.

    Don Wilson

  6. #6
    Super Moderator bmorgil's Avatar
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    The adapter is worth some cash if you can find one, and good luck with that! Most people end up buying a new engine plate. Here is a picture with some dimensions someone provided. The adapter is a source of some interesting stories. Some believed that Willys made them so auto shops could use the 2A motor in a 3A. And while I am sure a few dealers and auto shops ordered them for that, after discussion with the remaining old timers here in Toledo, we learned that was not the case. The Willys plant was under some very tight budgets in the late 40's through the 50's. The adapter was originally made to use up excess inventory at the plant. This is why it is not uncommon to find an engine that does not match the Jeep it is in. Many jump to the conclusion that they don't have an original motor and that may or may not be the case. Mine for instance has a known original motor as I am the second owner and able to discuss its history with the original owner. Yet the motor is a 2A style out of a prior to 1950 truck with an adapter. Records were very poor and Willys definitely used what they had in the lean times. According to Wikipedia the adapter was produced by the Buckeye Steel Casting Company out of Columbus Ohio best known today for its longtime president, Samuel P. Bush, who was the grandfather of President George H.W. Bush and great-grandfather of President George W. Bush. Ha ha! These Jeeps are just full of history!
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    Last edited by bmorgil; 01-13-2022 at 12:17 PM.

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    WOW To see A picture of that casting is incredible. There is a number visible that appears to be 647318. Not sure about the last number but counting on "8" Do you believe that to be the part number?
    Everything else seems to require a cosigner for parts so it certainly not unusual for cash to be the answer. I certainly have some time before actually needing it but the quest is on!

    Thanks
    Don Wilson

  8. #8
    Super Moderator bmorgil's Avatar
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    Good luck Don. The part number was WO-647193. 647318 is probably the casting number from the mold, not necessarily the part number. You never know how someone might list one if they had it for sale however. I really think you should put your efforts into fabricating one. A machine shop could certainly fab up a nice one if cost isn't a problem. I don't think you will find one for sale. A rare part to say the least. It is sad but when most ran into this issue they just bought a new motor plate and threw the adapter away. If you had a crossover 2A to 3A the part was probably original, put there by the plant, making the Jeep even more rare. A lack of understanding and bad information of the times led many later buyers of old Jeeps to believe they did not have an original engine.

    You can get into an argument with some who are sure this couldn't have happened. I avoid these arguments as I know better now. It reminds me of LarrBeard's number 1 rule of Jeeps. "Never say Willys would never". Those who remember are getting few and far between. At the first Jeep Fest in 2016 here in Toledo, I did get to talk to a few old fellows who worked and managed at Willys Overland in their teens and 20's. Some crazy things happened there after WWII and the Korean war. Willys ran out of money and records more than a few times. When we asked about how they kept track of what was being used where the answer was usually laughter! The Trucks suffered the most as they were not selling. Stories of serial number swapping for model year changes were common. LarrBeard has explained to a few about strange Truck occurrences. As these old fellas leave us so does this history.
    Last edited by bmorgil; 01-14-2022 at 07:22 PM.

  9. #9
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    Thanks for the clarification of the casting part number. Your advice is appreciated and I will not obsess over this part. The system I currently have has apparently worked for who knows how long. It is not beautiful but functional.
    WILLYS was obviously fighting for survival and probably adopted an "any thing goes" mode.

    Thanks,

    Don Wilson

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