340 .030 bore piston

Small Block Mopar Engine

  1. 72dustervs

    72dustervs Well-Known Member

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    Quick question before destroy or buy wrong , I bored out my 340 to .030 and looking at summit ring compressor non adjustable size 4.030 , is this the correct size needed ?
     
  2. Scody21

    Scody21 Just send it

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    Get an adjustable one. Can use for other projects in the future...
     
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    • 72dustervs

      72dustervs Well-Known Member

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      I had a cheap adjustable and it moves to much and cant get the bottom 3rd ring to get past it as its the thinner ring an shifts just enough to cause an issue
       
    • Plymouth 65

      Plymouth 65 Floorable Deplorable

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      A 340 0.030 over measures 4.07 65'
       
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      • Demonic

        Demonic Well-Known Member

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        It is a challenge to get new pistons and rings in a fresh bore. Two sets of hands helps, and plenty of oil. Adjustable ring compressors take some getting used to. Your piston-to-wall clearance should be checked too. No offense, but if you know you bored it .030" over, you should know your bore size.
         
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        • mechanicmark

          mechanicmark Well-Known Member

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          You need a 4.070" tapered ring compressor. (4.040+.030 overbore)
           
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          • CRUZE 418

            CRUZE 418 FABO Gold Member FABO Gold Member

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            Post #6 is correct.
             
          • krazykuda

            krazykuda Well-Known Member FABO Gold Member How-To Section Editor

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            • dano

              dano Evil Handy Man

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              Don't forget rod booties. I hate being the guy to keep the rod bolts for hitting the crank and keeping it aligned. My dad send pistons in like he is hitting a grand slam.
               
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              • 72dustervs

                72dustervs Well-Known Member

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                Its always good advice , I always take care in the process , my cheap ring compressor is my biggest issue , thanks for the reply
                 
              • 65 Cuda 340

                65 Cuda 340 FABO Gold Member FABO Gold Member

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                Just FYI - LA standard bore sizes are:

                273 - 3.625
                318 - 3.91
                360 - 4.00
                340 - 4.04

                Stroke on all but 360 is 3.31
                360 stroke is 3.58
                 
              • toolmanmike

                toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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                "cheap" is your problem.
                 
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