3B main/con rod bearing swap pictures!

Discussion in 'Diesel Tech and 24 volts Systems' started by amaurer, Oct 17, 2008.

  1. amaurer

    amaurer SILVER Star

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    4,391
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    Longmont, CO
    I'm pulling a lostmarbles here and made a thread before I've done the work. :D

    I'm going to pull the pan tonight when I get home form work and give it an evening or maybe all night to drain so, hopefully, I get less oil in my face.

    But before I get going, post up any tips you have. For example:

    -Can I somehow create new problems for myself by doing this? In the 40-tech forum, some people said swapping in new bearings is :hillbilly:

    -I'm not regrinding the crank, obviously, so is there any benefit/need to check clearances with the plastigauge stuff?

    -Apart from coating the bearings with some oil and bolting them back in, anything else that needs to be done?
  2. Big Blue 84BJ60

    Big Blue 84BJ60

    Messages:
    396
    Location:
    brampton ont
    dont worry boot the plasti guage unless the bearings slide in with no resistance
    and coat them with whit lithium greese instead of oil
    if your affraid of scratching the crank use something other than a screw driver/something steel to push in the bearings if their tight like a brass punch or something aluminum/copper
    other than that it was straight foreward for me
    good luck
  3. Zekester

    Zekester SILVER Star

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    894
    I've used a piece of white teflon/nylon stock whittled into a stick...if you leave a fat flat on one end, and a skinny flat on the other, you can still tap the flat with the skinny on the bearing and it wil push it in...you lose moet of your tap to the flex of the material, but it will still push it in...
  4. I'd still check clearances of the new bearings. You don't want them too tight and if you don't check you don't KNOW!!

    To me it's cheap insurance!
  5. brownbear

    brownbear Mod in Hibernation Moderator

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    6,627
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    True North Strong and Free
    why are you replacing the con and main bearings? Que...


    I second checking with plasitgauge to see if its in spec.
  6. amaurer

    amaurer SILVER Star

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    I'm replacing them for piece of mind. 3 months ago I found some large metal chunks in the oil pan. This month I'm finding oil pressure a little lower than I'd like it, and I have a knock when things are cold. Might be the bearings, might not be, but I'll sleep better.

    Sadly no one had replied and I've already dropped the pan. Maybe I can get a friend to swing by with some plastigage... sigh... but probably not.
  7. amaurer

    amaurer SILVER Star

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    ****!! I just bent one of my new main bearings, the plastic tool slipped under it while i was tapping it in - comparing it to a "good" bearing its now about 1/32" wider. It still fits into the cap fine, which pushes it back into shape.

    The old bearing is worn, but still had 0.001" oil clearane. Would you resue the old bearing or put in the new one (will the cap push it back to the proper shape?)?
  8. amaurer

    amaurer SILVER Star

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    Ok, well I'm "done", but this turned out to be a disaster.

    Anyway, first just a little engine porn, lostmarbles style. Its pretty easy, actually, to do this, just drop the pan, then pull the bearing cap, then use something plastic to tap the upper bearing out from around the crank. Installation is the reverse.

    I made three different plastic tools to tap out the upper half of the bearings - one that was fairly rigid but tapered to a point for getting the first 3/4" of the bearing out. Then a thin and super flexible piece for rotating most of the bearing out. And finally something like a thick plastic drift for tapping them back in.

    Here are pics of the bearing caps removed, me tapping the upper shells out, and the removed bearings. I'm not a bearing-ologist, but I don't see anything alarming there.
    IMG_4255-800.jpg IMG_4253-800.jpg IMG_4262-800.jpg
  9. amaurer

    amaurer SILVER Star

    Messages:
    4,391
    Location:
    Longmont, CO
    Bearings.
    IMG_4280-800.jpg IMG_4281-800.jpg IMG_4282-800.jpg
  10. amaurer

    amaurer SILVER Star

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    4,391
    Location:
    Longmont, CO
    So this was my first time with the amazing "plastigage" (which, if you've never bought before it can actually be a chore. Autozone has it, but none of the teenagers know how to sell anything but oxygen sensors. Any time you ask for "plastigage" or "the wax things for measuring bearing clearance", they'll walk to over to the tire pressure gages and start looking confused. You need to find the one greyhaired dude in the shop and ask him, who will say "oh sure" and get them for you. Took me two Autozones and a Napa before I realized what was going on...)

    Anyway, here is a shot of the plastigage which you just cut a bit off and lay it on the bearing, and then torque the cap in place. It works fine, but torquing the main caps to 145ftlb is tough when you're on your back, and this means you get to do the whole thing twice per bearing.

    I measured a couple of the old bearings which were still in spec, nothing was over 0.002" (The rebuild point is over 0.0059"). All of the new ones are between 0.001" and 0.002"
    IMG_4259-800.jpg IMG_4258-800.jpg IMG_4260-800.jpg
  11. amaurer

    amaurer SILVER Star

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    Now heres where the ****-show started.

    My plastic tool slipped between the crank and #4 main bearing as I tapped it in. The bearing bent slightly, so that it was about 1/32" wider than it should have been. If you pressed it into the bearing cap it'd go in and the cap appeared to hold it in the proper shape, however I decided not to use it.

    I reused the original bearing, as I wasn't having any specific bearing problems. It wasn't the best looking of the bunch, but it didn't seem like it was in terrible shape. I didn't want to use a different bearing as I assume they've all worn -in differently.

    I wonder: I also didn't want to use half of a new bearing, although could I use a new shell in the bottom where the wear is heaviest?? I left the pan off for the night so I could think on it...

    Here is a shot of the bearing I reused, bottom half is on the right:
    main4.jpg

  12. amaurer

    amaurer SILVER Star

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    And the **** show #2 is - SOR's conrod bearings don't seem to fit!!! Maybe I'm being silly, as they almost fit, but I need someone wise in these ways to tell me whats up.

    The stock bearings need to be pressed into the caps a bit - they're designed to be just slightly larger than the caps so the cap provides the proper curvature.

    The bearings from SOR appear to be just baaaarely too small, they just drop right into the bearings caps and sorta spin around in there (except for the tab). The circumference is also a bunch shorter - if I installed both halves there would be almost 3/8" cap between the end of the upper shell and the lower shell?!

    Maybe this doesn't matter, but I think this might be a B or 2B bearing, which, if memory serves, are slightly smaller than a 3B.

    Here are some shots of the size differences:
    IMG_4252-800.jpg IMG_4272-800.jpg IMG_4273-800.jpg
  13. amaurer

    amaurer SILVER Star

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    Given that I wasn't sure about the SOR bearing sizes, I didn't use them, but I did pull all the con rod caps and inspect the bearings, and use a plastigage.

    The clearances for all bearings were good, right at the tightest end of the standard specification. Some might have actually been a little tighter, but whats a guy to do? Sand the bearing, heeeheee?

    I dont know how to "read" bearings, so here is the worst of the bunch (#3, if I recall). What do you think?
    IMG_4269-800.jpg
    Last edited: Oct 18, 2008
  14. amaurer

    amaurer SILVER Star

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    4,391
    Location:
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    And lastly, do I need to reprime the system? I did have to remove the pickup tube and screen, however it had already drained, and no significant amount of oil came out of, well, anywhere. As far as I can tell I didn't do anything that would have disturbed the pump's prime, however, what do I know? Your thoughts, oh wizards of Mud??
  15. I would do what I do every time I start up. Keep OFF the skinny pedal till the oil pressure comes up.
  16. lostmarbles

    lostmarbles SILVER Star

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    Looks like your kiwi PO can't have been that bad after all Drew.
    I hope I find my old bearings to be as good as those when I eventually get right into the bowels of my engine. (Distant future I hope :D)

    There's certainly no sign there of where those metal fragments (that you found in your sump some time back) came from. And obviously neither set of bearings was responsible for your "knock".

    As far as your NEW big end shells are concerned - I'll be interested as to what SOR say about them. They certainly look to be the wrong ones to me but yet the box is labelled correctly.

    Perhaps you can send them these pictures (or just ask them to look at this thread) and then give you some advice on what they think has happened.

    :cheers:

    PS
    I understand your urgency to get your cruiser up and running. I'm not fitting my reconditioned injectors just yet because at the moment it is vital that my cruiser remains "on standby ready for action".
    You never know what is going to go wrong - Even in a job that appears very straightforward. - Particularly when working on OLD vehicles and when we ourselves (and our parts suppliers) often make c#ckups!)
    Last edited: Oct 19, 2008
  17. crushers

    crushers post ho SILVER Star

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    Tara Ontario
    white lithium grease shoudl be used to prevent start up scoring.
    i never followed this thread but i guess i shoudl have..
    mains have had a pice of dirt or metal score a coupel of the bearings...no biggie
    the bearings from SOR are too small and could have lead to problems down the road.
    all in all the bearigns all look quite acceptable...
    nice thread
  18. amaurer

    amaurer SILVER Star

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    FYI, I did lose my oil pump's prime somehow. Pressure wasn't coming up so I shut it off and overfilled it a bit - worked like a charm.
  19. Dougal

    Dougal

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    4,396
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    Kiwiland
    What size are the mains and big ends?
  20. amaurer

    amaurer SILVER Star

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    4,391
    Location:
    Longmont, CO
    Main journals are 69.98-70.00mm, bearing thickness 2.480-2.485 OR 2.485-2.490mm

    Big end journals are 60.98-61.00mm, bearing thickness 1.480-1.485 OR 1.485-1.490mm

    [Note the the BE journals for a "B" are 58.98-59.00mm. That is a ~6mm difference in circumference between the B and 3B, which looks roughly like the difference seen in my photo - looks like I got B bearings.]

    EDIT: Incidentally, SOR is telling me they sell them all the time and clearly its my engine that is "different". They said they'll take em back, but only after the inspect them and decide what their restocking fee would be... thats some bull**** right there.
    Last edited: Oct 20, 2008

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