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Thread: Engine identification ?

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  1. #1
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    Engine identification ?

    Just hauled in 3 Cj's . a 51, a 48, & a 46...
    on the 51 CJ3, the engine in it now, has what appears to be the casting # on the lower right side of the block, 641087-L-W10-A-NA. Add:
    The Head says " Kaiser -Super Sonic" on it also..
    Can you guys help me to indentify what this is ?
    Thanks in advance
    Last edited by Rufus39; 09-29-2017 at 04:04 PM.

  2. #2
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    To bring you light for your car

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    Wow, my last post had to go through a moderator. I haven’t seen that before. It was a link to another forum that I found on google by searching for “Kaiser supersonic head”.

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    Super Moderator LarrBeard's Avatar
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    Unless someone swapped it, the '51 CJ-3 should have the L-head 134 engine (the flathead engine). Kaiser and Willys were interchangeable back then, and a lot of one fit the other - with just minor differences in marking.

    While there may have been minor differences between Kaiser Supersonic and Willys Overland originally - at this late date they are the same.

    You probably have a garden variety L-134 that someone swapped the head - or Willys borrowed parts from the other side of the house one week in 1951. Not at all unusual back then.

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    Super Moderator gmwillys's Avatar
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    I'm not sure on how much truth there was to it, but I read somewhere (ewillys) that the Kaiser Supersonic heads were thought of a performance enhancer. The compression may be a bit higher, but I haven't noticed any difference in my 46 CJ2A. The Super sonic head was on there long before we bought it, but compared to other Willys L134, they act about the same.

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    Super Moderator LarrBeard's Avatar
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    AS you look through the really old stuff, Kaiser allegedly had different heads - like high altitude heads and such. Supposedly, they were originally painted different colors - but the more suspicious of us believe that the biggest difference was the paint.

    As far as a 5 HP boost with a Kaiser Supersonic head, the total redesign of the L-134 to the F-134 only gave about 10 HP improvement. I doubt that a different head would make that much difference.

    Most old L-134's got that boost after about 5 or 10 years when you had to plane the head to cure the warp after a blown head gasket. If the engine was rebuilt, it was not unusual for the engine serial number on the water pump boss to get removed when the top of the block got cleaned up as well. Good shops would restamp the number elsewhere on the block so it wasn't lost.

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    Quote Originally Posted by gmwillys View Post
    I'm not sure on how much truth there was to it, but I read somewhere (ewillys) that the Kaiser Supersonic heads were thought of a performance enhancer. The compression may be a bit higher, but I haven't noticed any difference in my 46 CJ2A. The Super sonic head was on there long before we bought it, but compared to other Willys L134, they act about the same.
    The hp rating is made at 4000 rpm. I can’t imagine spinning one of these engines that fast very often. The difference at lower rpm would be less and could become nonexistent when combined with other variables.

    It would have been nice if Willys or Kaiser had published some information about different heads available. I just had another look at the maintenance manual and so far all I see is a 7:1 compression ratio listed. My parts manual lists 2 part numbers. The first one listed is for the 6.48 head. The second one has a part number lower in sequence and says “(up to engine serial no......)” which leads me to believe it was an earlier head. My parts manual is from Willys-Overland. My service manual is from Kaiser. I wonder if a Kaiser parts manual may have more information.
    Last edited by 51 CJ3; 01-24-2018 at 10:02 AM. Reason: Correcting manual sources

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    My censored link mentioned an extra 5 hp and it was suggested it would have come from one of the Kaiser cars.

  10. #10
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    One of the posts I was reading claimed they had a supersonic head laying next to a regular head and they were different. It was suggested the supersonic head allowed for a higher compression ratio. I’m not an engine guy but I know increasing the compression ratio from 7:1 to 8.5:1 on a Lycoming O-320 is good for an extra 10 hp (published data easy to verify).

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