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304 Engine Stand Mounting Question

Discussion in 'Intermediate CJ-5/6/7/8' started by rusty72cj5, Feb 9, 2020.

  1. Feb 9, 2020
    rusty72cj5

    rusty72cj5 New Member

    Florida
    Joined:
    Jan 24, 2017
    Messages:
    17
    My bellhousing was already removed and the bolts long gone when I got the project. Wanted to bounce this off someone who has done it before. Mounting my 304 to the engine stand bracket. The two 7/16-14 bolts at the bottom corners thread in fine. The top two 3/8-16 bolts go in about quarter inch and the become extremely hard to turn, mangling the threads on grade 8 bolts. They aren’t bottoming out by a long shot before this happens. Seems to be all four of the 3/8 holes when I test the others. Is this normal or could the bolts be a different thread? Don’t want to force it and cause damage. 1972.
     
  2. Feb 9, 2020
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    20,601
    The parts book says there are 4ea 3/8"-16 by 2 3/16" long bolts for all V8s, 1974-80. A '72 should be the same, but it would be good to look closely at the threads to see if they match. A mismatched thread will only go in less than a turn without forcing it. Measure the bolt length and the thickness of the bell to see how far they should be threading in.

    The weight is mostly on the bottom-most bolts, in tension. The upper bolts don't do much in the car other than keep the alignment of the bell with the engine. So using bolts that only thread in 1/4" would not have much effect on the assembled drivetrain. If the bolts don't go in more than that, the rest of the threaded hole could be corroded and/or filled with dirt and other debris.

    How deep are the threaded pockets that only thread in 1/4" now? I would expect them to be threaded to near the bottom when the engine was new. A bolt is not the right tool to clear the threads. Instead , you should use a bottoming tap and lots of lubrication. I'd use a light oil like Liquid Wrench or PB Blaster or ATF mixed with some solvent in a pump oiler. Buy the right tap and run it in a little and out completely, cleaning the threads and flutes with lots of lube as you go. Don't force it - run it in a little, clean, run it in a little more, etc.
     
    Last edited: Feb 9, 2020
    Ol Fogie likes this.
  3. Feb 9, 2020
    Ol Fogie

    Ol Fogie 74 cj5 304, 1943 mb

    Jasper
    Joined:
    Nov 24, 2019
    Messages:
    129
    x2 on what timgr said very good advice, to recap again be sure to get your self a bottoming tap.
     

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