anyone ever rebuilt a 4.2??

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  • glbft1
    1st Gear
    • Dec 2006
    • 149
    #1

    anyone ever rebuilt a 4.2??

    thinking about rebui lding my 4.2 runs fine no coolant loss just getting up there in miles 225.000 still has good comp 145-150 per cylnder I have one that is at 135 but the one next to it is 145 sooo should i do a rebiuld now before it ****s the bed or will this thing run well into the 300000 mile range any feed back would be great.
    Thanks
    Greg
    Tags: None
    • CliftonRover
      3rd Gear
      • Mar 2007
      • 351
      #2
      I know the 4.2's have had problems with their bottom ends but other than that aren't they the same as a 3.9? you could check wear on the rocker assemblies and lifters and cam I guess. you could also use sea foam in the fuel and engine oil to try and clear out any carbon build up. then use a can of restore in it and recheck your compression. sounds like you take good care of the motor, I would avoid tearing it down if you can. sorry if i wasn't much help.

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        • 57loboy
          Low Range
          • Sep 2007
          • 74
          #3
          There are many of these engines with more than that mileage on them. The bottom ends of these are not weak in any way. So long as they've not been overheated due to bad head gaskets/etc., the cylinder liners are ok - many high end engines use sleeved bores. Remember, the LR V8 is nothing more than a Buick 215 V8... Replace the timing chain, cam, lifters and rocker shafts is about all they need. When I did the heads on mine at 143k, the crosshatching was still visible in the bores.
          I've got 153k on mine now with zero issues and just bought another with 209k on the clock (bottom end never touched) for parts. Only reason it's a parts truck is the front driveshaft broke and trashed the transmission. I'll be keeping that 4.2 for rebuild when I feel like doing it.
          '95 RRC LWB (white)
          '95 RRC LWB (Avalon Blue) - sold
          '95 RRC LWB parts truck ready and waiting to donate to the cause...

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            • CliftonRover
              3rd Gear
              • Mar 2007
              • 351
              #4
              I wouldn't have said anything about the bottom ends except I was at my buddies rover shop the other day he had 2 4.2 blocks both with broken bottom ends. As long as the engine has been well maintained there shouldn't be any problem. I have a lot of faith in the 3.9's (same block?) I run, they work extremely hard and have never had a problem.
              as any push rod v8 they will wear cams and lifters and such stuff, but only over long periods of time, or if inproperly cared for. one thing to check might be the timing chain, I have had a few that came to me with stretched chains.

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                • rover4x4
                  Low Range
                  • Mar 2008
                  • 20
                  #5
                  WHat are some symptoms of a stretched timing chain?

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