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Buick 231 Specs?

Discussion in 'Early CJ5 and CJ6 Tech' started by Heatseeker, Mar 4, 2012.

  1. Heatseeker

    Heatseeker Member

    Does anyone have engine specs for a 231? I'm looking for bearing sizes & clearances, cylinder bore size, torque values, etc. I just finished the teardown on my 231 and I need to check things out before I start buying parts.

    Either my google-fu is failing me or the info just isn't available on the 'net.

    Thanks in advance for any info.
     
    Heatseeker, Mar 4, 2012
    #1
  2. w3srl

    w3srl All-around swell dude Staff Member

    A good place to start would be the factory service manual (FSM). Also, any machine shop worth doing business with will be able to tell you what you have and what you need int he way of parts. They will also almost certainly be able to get you at least competitive pricing on the parts because of the sheer volume that they deal with.
     
    w3srl, Mar 4, 2012
    #2
  3. nickmil

    nickmil In mothballs.

    What year 231? Is it odd fire or even fire? Huge difference there. Lots of changes in 231's over the years. I have a few fsm's that cover them but need more info.


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    nickmil, Mar 4, 2012
    #3
  4. Heatseeker

    Heatseeker Member

    Sorry, it's a 1978 even fire.

    By the looks of things, if I can get the specs, I may not have to take any of the shortblock to the shop. I suspect the PO did a rebuild. The crank journals look nice and there isn't much of a ridge in the cylinder bores. I'm finding between .003" and .004" bearing clearances, which isn't too bad. I hoping for a ring and bearing replacement, a quick hone, a valve job and reassembly. That would fit my budget nicely...:D
     
    Heatseeker, Mar 4, 2012
    #4
  5. Twin2

    Twin2 not him 2024 Sponsor 2023 Sponsor 2022 Sponsor

    I would still take block to machine shop and have it dipped . and have cam bearing replaced
     
    Twin2, Mar 4, 2012
    #5
  6. nickmil

    nickmil In mothballs.

    Main journal diameter 2.499" with .0015" max out of round. Clearance .0003-.0017" . Endplay .004-.008"
    Crank pin diameter 2.2495-2.2487" Rod side clearance .006-.020".
    Cylinder bore 3.800". Out of round .0005" max
    Taper .0005" max. Piston to bore clearance .0008-.0020".
    Piston ring groove clearance compression rings
    Top. .003-.005"
    2nd. .003-.005"
    Ring end gap compression. .010-.020"
    2nd ring. .010-.020"

    Oil rings:
    Groove clearance .0035" max
    Gap .015-.035".

    This is from my 1978 chev Monza fsm.



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    nickmil, Mar 4, 2012
    #6
  7. Heatseeker

    Heatseeker Member

    ^That's what I needed! Thanks a million!^

    I have a hot tank at work, so I'll be doing the dip myself. And I have everything needed to do the cam bearings here at the house. Hopefully with the above info and some measurements, I should be avoiding any block/crank work from my local shop....
     
    Heatseeker, Mar 4, 2012
    #7