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signs of rod bearing failure?

Discussion in 'Early CJ5 and CJ6 Tech' started by Thunderpig, Mar 11, 2008.

  1. timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Something like this means an error in assembly or machining, a plugged oil gallery, or another equally drastic defect that I can't think of now. Nothing you did or could have done would have prevented the bearing failure - it was doomed from the start. I'd guess it got no oil - ran fine till the assembly lube wore out. The bearing metal (a soft gray alloy) is worn away and you are looking at the copper backing.
     
    Last edited: Mar 14, 2008
  2. w3srl

    w3srl All-around swell dude Staff Member

    I suppose you *could* try to polish the crank while it's in there, but I'm not optimistic out that. It's very possible that whoever reassembled the engine might have nicked a rod journal with one of the rod bolts on reassembly, or a piece of crud got left inside the cross-drilled crank. Be sure to use fat pipe cleaners to clean that passage out and use plastigage to check the tolerances on that journal when you put it all back together.

    On second thought, what the heck? Even if it doesn't work, you're only out a bearing, a gasket and a few quarts of oil.
     
  3. Thunderpig

    Thunderpig Member

    Update:

    Pulled all rod bearings... all were worn just as much. Pulled the Center Main bearing and it is also scored and worn. Went and bought a engine hoist :) will pull the entire engine and take it in for a re-rebuild! Talked to the people that built it for me and they stand by their word and will not charge anything for the re do.

    Will have to have work done on the crankshaft to get it back to new. I'm feeling pretty good now that I know the problem and there is an end in sight.
     
  4. StraightToPlaid

    StraightToPlaid Ludicrous speed!!!!

    Sounds like you have a good rebuilder.

    It's weird how that happened though, maybe junk got in the oil?
     
  5. tinker

    tinker GNGPN

    if they all had that amount of wear you may have a oil pump problem the wear didn't look like it came from the oil journal hole were the dirt would be.glad to hear the builder will fix it up for you.
     
  6. Rondog

    Rondog just hangin' out

    Still a big ol' honkin' drag though......
     
  7. jeeper50

    jeeper50 jeeps 'till I die

    Looks like undersize bearings on a standard crank. especially since they all look like that.
     
  8. cpt logger

    cpt logger Member

    Probably not an undersized bearing on a standard crank. When this is done the crank will not turn. I have seen this done, seizes it right up. You can only install one of them, as the crank will not turn to allow you to install the next one. My guess is lack of oil on start up. Did you pre-oil the engine before you started it for the first time? As I recall, you said it had been years between the overhaul and your starting it for the first time. Even if it was not the first start-up, that is a very long time to store a freshly overhauled engine without "pickling" it. When an engine is stored for that long, it should be at least pre-oiled before start-up. Best is to put some oil in the cylinders and let soak for a few days, then pre-oil and start after the engine has built up some oil pressure. You have a VERY good rebuild shop. Let us know what the rebuilder says is the probable cause. I am very curious as I used to work in an engine rebuild shop. Thanks. Matt W.
     
  9. Thunderpig

    Thunderpig Member

    Matt,
    actually it was only a week or so between the engine rebuild and start up. I have been trying to get it to run right for a long time though. Sorry for the confusion. You bring up a question in my mind though about initial start up and lack of oil. When I picked up the engine I asked about the procedure to start it up. I was told to get rotella T 10-30 and fill it up. Start it up, run it @ about 1800 rpm for 20-30 minutes and then change the oil and filter. Then time it and tune it. No mention about pre oiling or priming the engine with oil, so being my first engine rebuild I didn't do any pre oiling or priming. :? Was I supossed to?
    And if so... How?
    I did watch the oil pressure light closely and it immediately went off indicating good oil pressure within a second or so of start up.

    The engine shop guy doesn't know for sure what caused it but hypothesizes maybe some shavings in the oil filter assembly or line even though he said they cleaned it before re assemlby. The engines previous failure was a broken exhaust valve on one cylinder. He does think it was metal shavings from something.
     
  10. cpt logger

    cpt logger Member

    You did fine, the pre-oil and oil soak are only neccassary for engines that have been a while between rebuild and start up. I also am sorry for the confusiion. My posts are often long to avoid this confusion. It sometimes even works!:)
    Then yes, if you had oil pressure right away, it probably was metal shavings in the engine somewhere. In this case the rebuild shop should stand behind the rebuild. It sounds like they are doing right by you. If they do, and all is well after the new rebuild, then get the word out that they treated you right. This helps the shop stay in business, and you want them to be in business in case you have need of them again. These things sometimes happen and every now and again we do not find out where the metal came from. I am sure that the shop will try very hard to find the source of the shavings, so that they can prevent it in the future.
    Well, it sounds like things will work out for you in the end. I am sure that no one wanted to delay you driving your Jeep. Let us know how things turn out, Matt W..