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fudge.

Discussion in 'Early CJ5 and CJ6 Tech' started by Howard Eisenhauer, Jun 30, 2015.

  1. Jul 7, 2015
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    5,860

    It's actually been a number of years since I had the work done- the engine sat bolted to a stand with a plastic bag over it until last year. The engine shop in question is the only game in town, once upon a time they had a very good reputation but somewheres in the last 20 years or so they've lost that. I wasn't aware of their issues until after I had got the engine back. In point of fact after I got it back one person told me that he had his M38 L head rebuilt there & a rear main failed within 200 miles.

    They did not do a proper cleaning on the block, it wasn't hot tanked & they did not remove the gallery plugs- when I did oil came running out :rofl:

    And this- :shock:

    [​IMG]


    [​IMG]


    The polishing on the crank is something I'm willing to undertake myself, there's no trace of wear at all, all I'd be doing is brightening it up a bit & removing the dark rings left by in the middles from the bearing oil passages.

    With the time that's passed, plus I can't find the work order anymore, plus I can't guarantee that with all the work I did on it I didn't contaminate it myself, plus their current reputation I really just want to avoid any future dealings with them, including letting them get their hands on my spare, apparently good, crank.

    H.
     
  2. Jul 7, 2015
    Chilly

    Chilly Active Member 2019 Sponsor

    Joined:
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    I make a living specifying, purchasing, validating, and using measurement systems. Good rule of thumb is to use a gauge with 10X better resolution than the tolerance band you are checking. If a part has a 0.010" tolerance then gauge needs 0.001" resolution. A crank probably has a tolerance of 0.001" max? So one should use a gauge with 0.0001" resolution.

    Now that is only a guide to get started on the right foot. Next comes a proper gauge study to ensure the gauge is both repeatable (gives same result for a given operator) and reproduceable (gives same result for different operators). Standard study uses ten parts and two inspectors. Each inspector measures each part twice (mix them up to keep it fair, inspector does not see the recorded results), giving 40 pieces of data. Running the statistics, one aims for a gauge error of less than 10% of the feature's tolerance band. More difficult to achieve than one would think.

    A GREAT set of digital calipers will not pass a gauge study for a diameter with 0.001" tolerance band, but it's all about confidence. The statistics I use assumes one wants to be 95% confident that the measured result is the actual result. That's not to say that regular folk buying their own tools requires the same confidence, or that the crank actually has to meet the 0.001" tolerance to run reliably for quite a long time.

    Chilly
     
  3. Jul 7, 2015
    Glenn

    Glenn Kinda grumpy old man Staff Member Sponsor

    Apopka, Fl
    Joined:
    Sep 21, 2002
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    9,159
    Have you torn into it further yet? Just wondering about further issues being discovered. FWIW machine shop issues like that are not isolated to your neck of the woods.
     
  4. Jul 7, 2015
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    5,860
    I got it out Sunday but I'm waiting on borrowing an engine stand before I can remove the crank, should be this coming weekend. I really wish I had a crank & bearings ready to put it right back in :(

    I did get the flywheel/clutch & timing cover off, the tranny spins in neutral & with the crank gear removed the cam will spin all the way around. No dropped intake valves either, I'm suspecting the residual resistance is smut in the #4 rod bearing.

    H.
     
    Last edited: Jul 7, 2015
  5. Jul 7, 2015
    Glenn

    Glenn Kinda grumpy old man Staff Member Sponsor

    Apopka, Fl
    Joined:
    Sep 21, 2002
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    Were the few miles of your test drive the only miles on the engine? I'm sure you ran it some before driving it? Personally I would be worried about some tiny particles of whatever having circulated through the rest of the engine lube system. I'd sure hate to have the cam go next. ;)
     
  6. Jul 7, 2015
    blevisay

    blevisay Oh Noooooooooooooooo! Staff Member Sponsor

    Portland Tn.
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    3,564
    Thinking out loud..........was the block lined honed by any chance?
     
  7. Jul 7, 2015
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
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    Nov 22, 2003
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    Not that I'm aware of, but one of the larger pieces of crud that was in the bearing groove was a shiny hard sharp curlicue of something or another. Definitely had a "shaved" look about it. :rofl:

    H.
     
  8. Jul 7, 2015
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
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    I had a couple hours total run time on it & a short drive around the house.

    Thanks for the kind thoughts about the cam :(

    H.
     
  9. Jul 7, 2015
    Glenn

    Glenn Kinda grumpy old man Staff Member Sponsor

    Apopka, Fl
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    Sep 21, 2002
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    :oops: Sorry if it seemed sarcastic, definitely not my intention.
     
  10. Jul 7, 2015
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
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    I didn't take it that way at all, you're showing concern for something I'd just really rather not think about just yet :shock:

    H.
     
  11. Jul 7, 2015
    uncamonkey

    uncamonkey Member

    Greeley CO
    Joined:
    Jun 2, 2009
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    2,105
    A friend used to machine parts that were for nuclear bombs, pretty much 0 tolerance. I'm sure any measuring device used was the best on the market
    I have a starrett dial caliper and an antique micrometer, 0" to 4". It took some time to calibrate the anvils. The caliper is handy but for real readings, the micrometer is the tool. A few years ago I read up a bit and saw how much temps can affect a reading. Set the micrometer to the standards included in the box. Held the micrometer for an hour and checked it again. noticeable difference.
    I'm still trying to teach the neighbor how to read a vernier caliper.
     
    Last edited: Jul 7, 2015
  12. Jul 7, 2015
    tarry99

    tarry99 Member Sponsor

    Northern California
    Joined:
    Oct 29, 2012
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    3,779

    Wow , Sorry for all of the problems you have encountered. Since dirt or metal may have contributed to the crank / bearing issue , are you planning to disassemble this and root out all the oil gallys and crankcase? While looking at the Block surface.........and not to add any more negatives to what you already have there........but that block surface sure looks rough gasket seal wise....also it looks like there may have been some welding repairs around those valve seats but maybe never resurfaced once done?

    I know these motors don't have much compression but you might want to take a nice straight edge and look across it and see what it reveals........At the very minimum a slight chamfer or bevel is a good Idea around those head bolt holes.........while also running a bottom tap in each one to clean the threads to make sure you can get even and consistent head torque...........not trying to add more work to your project, just trying to help see that go back together and stay that way! Good Luck!
     
  13. Jul 8, 2015
    Cap-n-Cray

    Cap-n-Cray I want to do this again.. Staff Member Sponsor

    Bainbridge...
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    Howard, don't know if you can use this in Canada...

    [TABLE="class: MsoNormalTable, width: 384"]
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    [TD] [FONT=&quot]Enter Promo Code: [FONT=&quot]ONEDAY[/FONT] | Offer Valid Until 7/8/15 at 11pm ET.[/FONT]
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    From ENCO... http://www.use-enco.com
     
  14. Jul 14, 2015
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
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    5,860
    OK, got the crank out on the weekend. Mains 1 & 2 look good but all the rod journals show at least some signs of scratching. :(

    Cam bearings look perfect (Take That Glen!) :)

    Here's the little bugger that caused all the consternation-

    [​IMG]

    The upper shell was stuck on there pretty good, took a bit of effort to pop it off.

    The crank got dropped at the shop today, initial impression is it can be polished up but we'll see for sure tomorrow.

    Interestingly I found another "mystery rod"-

    [​IMG]

    Never saw it the first time I had the plugs out because the engine was the other way up :rofl: I notice now that there's holes on the inside of the plugs that look like the rods are meant to fit into them, I'm wondering if they might be magnets...

    More to come,

    H.
     
    Last edited: Jul 14, 2015
  15. Jul 14, 2015
    Glenn

    Glenn Kinda grumpy old man Staff Member Sponsor

    Apopka, Fl
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    I'm glad the cam is good! :)
     
  16. Jul 24, 2015
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
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    Got the crank back Tuesday, I've spent the last few nights putting things back together- hopefully I'll have him running by Sunday evening.

    They were able to polish out the damage, plastigage shows .0015"- .002" on the mains, with the exception being .003" where the damage on the rear was. Rods showing between .0015"-.002" as well.

    Q.- while the rods are showing .002-ish I can actually rotate them, i.e. twist them, on the journals- I expected them to slide back & forth a bit but a twist? Could the bores/caps be that far out of round on the sides?

    re. The "mystery rods" it appears these things were inserted to either completely block off or severely restrict oil to the middle cam bearings. :shock: The engine was a factory rebuild, could this be a late design change, or the rebuilder compensating for excessive clearance doing bad things to the oil pressure?

    Enquiring Minds want to Know...

    H.
     
  17. Jul 24, 2015
    Glenn

    Glenn Kinda grumpy old man Staff Member Sponsor

    Apopka, Fl
    Joined:
    Sep 21, 2002
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    9,159
    I was wondering how it was going with the crank cleanup. Have you test fit just the rod bearings on the journals? Obviously to be able to twist the connecting rods is a show stopper. One could guess the steel rods were installed to regulate oil flow. I assume you are going to leave them out?
     
  18. Jul 24, 2015
    PeteL

    PeteL Member Sponsor 2019 Sponsor

    Hills of NH
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    "Could the bores/caps be that far out of round on the sides?"

    Plastigage would answer that, I believe. Or some careful work with a caliper guage or micrometer.
     
  19. Jul 25, 2015
    tarry99

    tarry99 Member Sponsor

    Northern California
    Joined:
    Oct 29, 2012
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    3,779
    Do you have access to some snap gauges and a Mic?..............you can assemble the rod with the bearing either in or out, torqued down and measure the bore and see how square it is.........were the rods reconditioned during the rebuild process?...........normally you should see signs of a cross hatch pattern in the rod journals if they have been recently re-sized.

    [​IMG]
     
  20. Jul 25, 2015
    Yooper John

    Yooper John Member

    Joined:
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    93
    I've been following this thread, and finally have to comment. I think you need to take this engine entirely down and verify every measurement from bare block on up. If you don't, I think there may be more disappointment in your future. If not equipped or comfortable doing this yourself, find a shop that is and have them do it. They are out there. It may cost some money, but it will limit your future heartaches. There have been too many variables in your project, and at this point you are half way there. Good luck.
     

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