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V6 rod bearings

Discussion in 'Early CJ5 and CJ6 Tech' started by Patrick, Apr 20, 2011.

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  1. Apr 20, 2011
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    The rod bearings in my "recently rebuilt" V6 are rattleing a bit. The engine had great compression and looked as though it was a recent rebuild when i put it in a year and a half; 6000 miles ago.
    I did replace the rear main seal at the time, and the rear main bearing did show some wear. Some how, the rear main seal didn't work great and it leaks a bit, causing the clutch to now chatter.
    Anyhow, should I...
    A) drop the pan, measure the rod journals, and slap some rod bearings in it.
    B) Pull the motor and put rods and mains in it, if the journals look OK
    C) Order a reconditioned crankshaft and bearings, and a new clutch and just be done with it.

    Here's the main dilemma...New rod and main bearings are like 90-100 bucks for a set, or I can get a crankshaft and (Sealed Power) bearings for ~$200..

    I guess I just need someone to tell me to suck it up and fix it right...:)
     
    Patrick, Apr 20, 2011
    #1
  2. Apr 20, 2011
    grannyscj

    grannyscj Headed to the Yukon

    Anchorage, AK
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    You don't have to replace all of them unless you want to. 1st thing I would do is pull the pan and take a look. If it's only one or two sets, I would just replace them and be done with it. The main concerns me some though. If it's bad go ahead and pull the motor. As far as the crankshaft, as long as its still got enough meat left for the next step in bearing size, I would just have it reconditioned.
     
    grannyscj, Apr 20, 2011
    #2
  3. Apr 20, 2011
    lamar

    lamar Member

    greenville sc
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    I myself would go for the the crank and matched bearings. Most likely you wouldn't have to worry about it again.
     
    lamar, Apr 20, 2011
    #3
  4. Apr 20, 2011
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Conventional wisdom says that, with a cast crank, by the time you hear the rod bearings knock, the journals have been damaged. But conventional wisdom is not always right.

    I trust your judgement that you're really hearing rod bearing knock.

    I'm not a big fan of working under the car, looking up. Since I'd be working on my own schedule, I'd likely pull the engine and inspect it looking down at it. Considering that this is a CJ, and the motor comes out and goes in without a lot of hassle.
     
    timgr, Apr 20, 2011
    #4
  5. Apr 20, 2011
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Unless things have changed, I expect you can get a crank kit for the same price as having your crank reconditioned plus bearings. Typically you'd mic the crank and get a kit one size under that, just so your core is acceptable.
     
    timgr, Apr 20, 2011
    #5
  6. Apr 20, 2011
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    It's rod bearings. They're a bit noisy off idle when cold, then when warm they rattle @ around 2500 RPM-up. If I just wanted to replace the rod bearings, I'd do it in the Jeep. Mains can't really be done in the Jeep easily unless i pull the timing cover/ chain and even then I'm not sure about doing the rear with the flywheel attached....
    I know the main journals have been machined .010" under per the stampiing on the bearing I had out, but right now i have no idea about the rod journals. I'd like to believe they're the same, but there's just no guessing.
     
    Patrick, Apr 20, 2011
    #6
  7. Apr 20, 2011
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    I'd guess that's correct. I found a .020/ .020 crank with bearings for $163 + shipping, and $30 core.
    So, if I had mine reconditioned, it'd be at least .020 under when it was done, plus I'd have to remove it and get it ti Albuquerque (100 miles away) and then get it back up here when done.
     
    Patrick, Apr 20, 2011
    #7
  8. Apr 20, 2011
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    Another factor is the clutch. Once I get the rear main seal replaced I'd like to replace the chattering clutch. Normally i'd drop the trans., but if I'm wanting to replace engine bearings, I might as well pull the motor to do the clutch as well. If the motor is out, it seems silly to just replace rod bearings, even if that's all it really needs.
     
    Patrick, Apr 20, 2011
    #8
  9. Apr 20, 2011
    Corveeper

    Corveeper Member

    Chanute, Kansas
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    Considering what all you’ve got going on I’d probably just pull the motor and go with the reconditioned crank and matching bearings. I’d probably still Plastigage the bearings though since your current problem is a tolerance issue.
    "Never time to do it right but always time to do it over." ~Crusty old Engineer I used to work with.
     
    Last edited: Apr 20, 2011
    Corveeper, Apr 20, 2011
    #9
  10. Apr 20, 2011
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
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    Since so much about the motor is "unknown", I'd pull it and do the crank and bearings; then you know exactly what you have and be done with it.
     
    jpflat2a, Apr 20, 2011
    #10
  11. Apr 20, 2011
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    Alright...going to take the engine hoist home and start from there.....
     
    Patrick, Apr 20, 2011
    #11
  12. Apr 20, 2011
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Suck it up and do it right:)
    Do it once the right way then you don't have to do it again soon
    You know this, sounds like you just need someone to reinforce that
    Posted via Mobile Device
     
    nickmil, Apr 20, 2011
    #12
  13. Apr 20, 2011
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    [​IMG]
     
    Patrick, Apr 20, 2011
    #13
  14. Apr 20, 2011
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
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    don't scratch the paint...
     
    jpflat2a, Apr 20, 2011
    #14
  15. Apr 20, 2011
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
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    :toetap:

    it's not out yet ??????
     
    jpflat2a, Apr 20, 2011
    #15
  16. Apr 20, 2011
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    Close. Un-bolt radiator, headers, bell housing, then out it comes..
    [​IMG]
     
    Last edited: Apr 20, 2011
    Patrick, Apr 20, 2011
    #16
  17. Apr 20, 2011
    jpflat2a

    jpflat2a what's that noise?

    Hermosa, SD
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    you could prolly stand it up on end with blocks underneath for support or just turn it upside down I suppose, with carb etc removed
     
    jpflat2a, Apr 20, 2011
    #17
  18. Apr 20, 2011
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    I'll just swing it upside down on the stand...Remind me to pull the water jacket plugs...
     
    Patrick, Apr 20, 2011
    #18
  19. Apr 20, 2011
    Project71-5

    Project71-5 BACON

    Gypsum, CO
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    Might as well do a full rebuild since the engine is gonna be out...:D
     
    Project71-5, Apr 20, 2011
    #19
  20. Apr 20, 2011
    cj6/442

    cj6/442 Sponsor

    Fallbrook, Calif
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    don't forget to pull the temp sender.


    and oil pressure line
     
    cj6/442, Apr 20, 2011
    #20
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