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1981 CJ7, blown engine

Discussion in 'Jeep CJ Builds' started by bbraunger, Jun 1, 2017.

  1. Jun 1, 2017 at 9:02 AM
    #1
    bbraunger

    bbraunger [OP] New Member

    Joined:
    Jun 1, 2017
    Member:
    #1511
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    Gender:
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    First Name:
    Beau
    Vehicle:
    1981 CJ7
    Joined this thread as I recently purchased a 1981 CJ7, took it mudding, and then on the way home, it was knocking and riding very "jerky". One block away from the mechanic's shop, I heard a loud bang and lost all power. Here's what the mechanic said:

    Found I was getting a intermittent spark, it would spark for a second right when it started cranking then the spark went dead. I checked all the electrical components in the distributor and they all checked out ok so I went to take the rotor off to check the reference pulse sensor under it and I noticed that the rotor was moving back and fourth by hand, it shouldn't be doing that. I pull the distributor out of the engine and the gear on it that runs on the camshaft is completely sheared off. So that means all that metal from that gear is now in your engine and has circulated throughout every thing. So the engine is pretty much junk unless you want to get it rebuilt. But at this point there's nothing more I'm going to be able to do with it.

    Any recommendations on an engine swap (i.e. 350 long block Chevy), or has anyone just had the engine rebuilt? It's a straight six, AMC, 4 speed engine. Any and all help is appreciated.
     
  2. Jun 1, 2017 at 1:49 PM
    #2
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

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    Welcome! I'm not much in giving help on this, but someone will pop in soon :)
     
    JKBob 25 likes this.
  3. Jun 1, 2017 at 6:24 PM
    #3
    JKBob 25

    JKBob 25 Well-Known Member

    Joined:
    Mar 22, 2017
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    #1197
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    First Name:
    Bob
    Jersey Shore, NJ
    Vehicle:
    2016 JK Wrangler Sport
    2" Superlift kit. 315/ 70/17.
    Ditto. Theres several members here that have experience with this. As Chris4x4 said.

    Also. Welcome to the site.
     
  4. Jun 2, 2017 at 9:15 PM
    #4
    OFFGRID

    OFFGRID Well-Known Member

    Joined:
    Oct 3, 2016
    Member:
    #317
    Messages:
    2,018
    Gender:
    Male
    First Name:
    Peter
    Houston
    Vehicle:
    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    A Chevy 350 is a pretty easy swap, and if you are going to have a machine shop rebuild your AMC 258, then you will probably come out cheaper if you order a basic GM crate 350 for under $2k from summitracing.com https://www.summitracing.com/parts/fme-350g8795/overview/. You will need the motor mount adapter (Novak-adapt.com, summitracing.com etc.) and you will need a motor to tranny adapter (Novak-adapt.com, advancedadapter.com, summitracing.com etc.) I strongly suggest that you run a TBI instead of a carb. Well worth the extra $500-600. FiTech probably makes the easiest TBI installation.

    That distributor gear you are talking about doesn't just strip out like that. My guess is something else inside the motor broke loose and lodged on the cam gear striping the teeth.
     

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