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  • Replacing Rod/Main Bearing Inserts?? 85 CJ 258 -I6

    Hi,

    I have a light tapping sound that sounds like a knock when I put my jeep in Drive. I don't hear it in Park. I don't hear it until the jeep warms up good. The jeep runs great and doesn't smoke or anything. It has 118,000 miles.

    My question is can I drop the Oil pan easily to install new rod bearings? How about the main bearings? Are they hard to install? Do you have to jack up the motor to get the oil pan off? I know the bearings must go back only (1) way to match up with the oil holes in rods and caps. I would mark them when I take them out.
    How do I know whether to go back with STD or .10 .20 or .30?

    Should a greenhand like me tackle this job? I just wanted to do something before it got worse and slung a rod.

    Thanks,
    Swampdawg

  • #2
    i would imagine if you cranked then around you could do the rod bearings from the bottom. mains are easy. if the motor has never been machined use only std size bearings. oil pan will come off w/o lifting the motor. keep the caps in the correct order, don't mix them up. replace the RMS while you're in there and really the oil pump and screen to if the extra $20 won't break you.

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    • #3
      Sorry FUBAR but you are wrong. Sometimes they come from the factory with oversized berings. Had several. The best way is to remove one and hope someone didn't do a nasty on you and ground just one journal(they sould be marked on the bearing. As for is it easy, yes, should a green horn tackle it, no. You could end up with more problems than what you have now.
      If you don't decide to heed my warning then make sure you keep all the dirt out of the crank area. Also make sure you use assembly lube when you put it togeather. Replace them one at a time(rod) mains you will most likely have to loosen them all and then replace them as they can get tight. Make sure you torque them down right.


      Originally posted by FUBAR
      i would imagine if you cranked then around you could do the rod bearings from the bottom. mains are easy. if the motor has never been machined use only std size bearings. oil pan will come off w/o lifting the motor. keep the caps in the correct order, don't mix them up. replace the RMS while you're in there and really the oil pump and screen to if the extra $20 won't break you.

      Comment


      • #4
        I don't know how you would jack the motor up to replace the mains, I have done just the rod bearings in the frame. I would start off with the standard unless you have the code on the block that states they aren't standard. Then use plastic guage to measure them to see if you have the right clearance.

        Comment


        • #5
          Originally posted by GPER
          I don't know how you would jack the motor up to replace the mains, I have done just the rod bearings in the frame. I would start off with the standard unless you have the code on the block that states they aren't standard. Then use plastic guage to measure them to see if you have the right clearance.
          If your jeep sits low you might have to jack up one side of the motor to get the pan off. You don't really jack up the motor, just make it roll to one side a bit.

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          • #6
            i've never heard of a motor coming from the factory with oversized mains. but i haven't heard everything by any means.

            as far as jacking up the motor, some vehicles require it. my old ford truck had a front sump that wouldn't come out unless you lifted the motor all the way against the firewall (book called for removal) and then you had to drop the pickup in the pan to remove it. installation was a nightmare because you had to blindly get the pickup from the bottom of the pan, then line up the shaft to the dist with the oil pump while holding the bolts and the oil pan.

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            • #7
              To get my oil pan off, I had to jack one side of the motor..if you look, it is too tight on the passenger side..no biggie, loosened the MM and used a bottle jack. It was sort of a pain though.

              Comment


              • #8
                Replacing Rod/Main Bearing Inserts?? 85 CJ 258 -I6

                Ok Guys, Thanks for all your responses. I am going to smoke it over and I am leaning toward finding a mechanic that works out of his home /garage.
                It sounds like it might be a little too technical for me. I want to make sure the bearings are the right size and torqued back right. I don't think I have the right tools and expertise.

                This is a very nice 85 CJ 7, I am the 2nd owner and I want to make sure the job is done correctly. I just don't want to spend the BIG BUCKs at the Big Garages. The jeep really does run good but just makes the tapping noise when hot. I am not sure that I could identify a journal problem or an odd undersized one. The lady I bought it from said it had never had any major motor work other than a timing chain and all new gaskets.

                Thanks Guys,
                Swampdawg

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                • #9
                  What is a RMS?

                  Does that mean Rear Main Seal?

                  Thanks,
                  Swampdawg
                  Last edited by swampdawg; 11-30-2006, 09:21 PM.

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                  • #10
                    Originally posted by swampdawg
                    What is a RMS?

                    Does that mean Rear Main Seal?

                    Thanks,
                    Swampdawg

                    as Fonzie would say:

                    correctamundo!

                    Comment


                    • #11
                      Thanks Fub!

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