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V6 Engine Code Mystery

Discussion in 'Early Jeep Restoration and Research' started by Rubicloak, Aug 1, 2018.

  1. Aug 1, 2018
    Rubicloak

    Rubicloak Member

    Nevada
    Joined:
    Jul 19, 2018
    Messages:
    66
    Hi all. I am in need of some help deciphering my 1971 CJ5 V6 Dauntless "Engine Production Code".

    VIN TAG COWL= 8305037 373185
    [​IMG]

    DASH STICKER = MAR 1971 VIN = 8305037 373185

    [​IMG]

    FRAME STAMP= 373185

    [​IMG]

    ***Stuff everyone already knows but putting it up anyway***
    VIN
    83 = Universal CJ-5
    05 = Open Body
    0 = Universal
    3 = LHD California, Fuel Evap Control
    7 = V6-225 With Emission

    373185 = Sequential Serial Number

    My 1 owner CJ5 (owner now deceased) has an "Engine Code Number" stamp of "DUH 002 R" The son does not remember the engine ever being replaced (does not mean it did not happen)


    [​IMG]
    [​IMG]

    D = Domestic
    Second letter denotes year cast ***cannot find reference to a "U" in any literature***
    H = V6-225 9.0 to 1 C.R. (2bbl carb)
    The three numbers = julian date or in my case the second day of the year
    No clue what the "R" Stands for in my case


    ***What I know from researching block stamps for Buick and Jeep***
    From below pic in Chilton 1967 = DNH or from "Service Manual Jeep Universal Series" N-1967
    From below pic in Chilton 1968 = DPH or from "Service Manual Jeep Universal Series" P-1968
    From below pic in Chilton 1969 = DRH or from "Service Manual Jeep Universal Series" R-1969
    From below pic in Chilton 1970 = DSH or from "Service Manual Jeep Universal Series" S-1970
    From below pic in Chilton 1971 = DHC or from "Service Manual Jeep Universal Series" T-1971 ***does not match***

    I found this on Team Buick's Forum
    "See attached page from the '74 Chilton repair manual Jeep chapter. This shows the 1967-71 Buick/Jeep V6 codes."
    [​IMG]



    Any help that anyone on here can give will be very much appreciated in solving this.
     
  2. Aug 3, 2018
    Rubicloak

    Rubicloak Member

    Nevada
    Joined:
    Jul 19, 2018
    Messages:
    66
    Anyone? Buehler, Buehler?
     
  3. Aug 3, 2018
    Twin2

    Twin2 wasn't me Sponsor 2019 Sponsor

    Virginia Beach, VA
    Joined:
    Apr 28, 2011
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    3,679
    from FSM
    scan0001.jpg
     
  4. Aug 3, 2018
    Rubicloak

    Rubicloak Member

    Nevada
    Joined:
    Jul 19, 2018
    Messages:
    66
    Sorry Twin2. I get this error when trying to open stuff people put on here? Can you give me the jist of the pic you put up?

    ECJ5 - Error
    You do not have permission to view this page or perform this action.
     
    Last edited: Aug 3, 2018
  5. Aug 3, 2018
    AtomicYJ

    AtomicYJ Sponsor Sponsor

    Richmond Hill, GA
    Joined:
    May 12, 2015
    Messages:
    67
    Since the service manual says its a replacement short block it may be from after the AMC buyout and Jeep just used the next letter in sequence instead of Jumping around like Buick did.

    Also the gist of the pocture is decoding the engine through Market, Year, Compression, and date as already noted. A for undersize crank, B for oversize pistons, S for service replacement, and R for short block after the date numbers.
     
  6. Aug 3, 2018
    Rubicloak

    Rubicloak Member

    Nevada
    Joined:
    Jul 19, 2018
    Messages:
    66
    Thank you, both of you. Hopefully I will be able to view what he posted and save it at some point in the future. So if I am understanding you correctly Atomic, at some point the PO had the engine replaced or at min needed a short block.
     
  7. Aug 3, 2018
    Focker

    Focker I Hate Being Bi-Polar, It's Awesome. Staff Member Sponsor 2019 Sponsor

    Tri-Cities WA
    Joined:
    Aug 18, 2014
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    5,898
    Try now. (y)
     
  8. Aug 3, 2018
    Rubicloak

    Rubicloak Member

    Nevada
    Joined:
    Jul 19, 2018
    Messages:
    66
    Boom! Thank you sir.
     
  9. Aug 3, 2018
    AtomicYJ

    AtomicYJ Sponsor Sponsor

    Richmond Hill, GA
    Joined:
    May 12, 2015
    Messages:
    67
    The way I read the TSM, the R is for a service replacement short block. Things happen to new new vehicles. My money's on the original engine needed replacement with a short block very early in that Jeep's life and it got replaced by a dealer.

    I'd be willing to bet Jeep kept using codes in alphabetical order and made replacement engines for a couple years following the buyout. That way dealers could still fully service vehicles and not alienate older customers.
     
    mike starck and Rubicloak like this.
  10. Dec 12, 2018
    truckee4x4

    truckee4x4 Member Sponsor 2019 Sponsor

    Truckee CA
    Joined:
    May 30, 2008
    Messages:
    77
    Figured I’d post this here...my engine stamp code on the right side below the exhaust manifold says “KM H.”
    20181212_GK_untitled shoot_Photo Dec 12, 6 51 23 PM.jpg

    Anyone have any ideas what the K means? the serial (VIN: 8322 A 16450) indicates 1966 which weirdly isn’t an option? Does the "M" mean the motor I have isn't the original one? Which letter is the compression ratio? How else could I figure this out by measuring?
     
    Last edited: Dec 13, 2018

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