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Now I've done it.

Discussion in 'Intermediate CJ-5/6/7/8' started by djljeep, Dec 17, 2010.

  1. Dec 17, 2010
    djljeep

    djljeep Meandering Aimlessly

    Western Maine
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    So i just got everything back together on my 73 with the 79 258 and got a little surprise... Block is cracked. straight line between the freeze plugs on the drivers side. I think i know the answer to my next question but... Will i have any success welding or brazing the crack? I know about welding cast and all of its difficulties and my dad suggested brazing it. I know there is no real way to fix it other than to replace the block, but this won't be a daily driver. I have the original motor from the jeep, but it needs an overhaul. If i can't weld it i think i will end up replacing the rings in the old block and putting the newer head on it if i can. I do have an entire 4.0 in the yard in a junk zj but i'm not sure i want to tear into that yet. Basically this jeep has been in the garage for over a year for a motor swap and I don't have the money to overhaul the other motor. I really want to drive this out of the shop, can i weld the crack?
     
  2. Dec 17, 2010
    sterlclan

    sterlclan Member 2022 Sponsor

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    worth the try its broke now wont be any more broke if it dosnt work....
     
  3. Dec 17, 2010
    djljeep

    djljeep Meandering Aimlessly

    Western Maine
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    thats pretty much what my dad said. I am getting ready to go take a picture of it and run it long enough to see if there is water in the oil.
     
  4. Dec 17, 2010
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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  5. Dec 17, 2010
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    You say it won't be your daily driver. Will it be something you take off road, away from "civilization" ?
    IMO, it needs to be reliable if you're going to drive it at all.
     
  6. Dec 17, 2010
    djljeep

    djljeep Meandering Aimlessly

    Western Maine
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    Alright. I just went and ran it for a little bit, driving it for the first time in over a year. the motor runs strong, which i find ironic. here is the crack(s)
    [​IMG]
    [​IMG]
    The oil has been showing a little high to start with and has MMO in it so i think this is just dirty oil not antifreeze in it, but you guys are the masters not me.
    [​IMG]
    [​IMG]
    Really it was great to drive it again, Ill be sad if i have to tear it apart again. live and learn i suppose. I'm not so concerned about the out in the woods thing because A, I never go alone, or atleast not in that rig just yet, B If it does let go wouldn't it just be re-cracking and leak coolant, which i could make up for by carrying adequate extra. C i would only do it untill i could get something else built to replace it.

    Now by saying that I have no intentions on running something that would be unsafe or "unreliable". I respect my friends that i wheel with i i don't want to thrust my lack of preparedness on their shoulders to get me out.

    My question is really, Will welding/brazing work at most for a year of very mild use or will it damage anything on the other side like the cylinder walls? But If you guys insist i put in a different block that is probably what i will do.
     
  7. Dec 17, 2010
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Sometimes coolant will get in the crank case but if in small amounts it won't get milky until it's run for a while. A check is with the oil still on the dipstick heat it up with a lighter or propane torch. If the oil starts separating and when it gets hot starts sizzling or snapping and popping it has water in it. Just like throwing water in a frying pan that has hot oil in it.

    You might be able to braze or weld that up but that is a really long crack. not to mention it's going between two core plug holes which most likely are cracked in the bores where the plug goes. You'd have to remove the core plugs, weld or braze it in there and try and seal that back up as well.

    Personally I'd wait a bit, save the money, and do it right.
     
  8. Dec 17, 2010
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Another option is a sealer like K&W block sealer. It's temporary, can make the engine a challenge to get apart later (including removing the cylinder head), but can sometimes get you buy. I don't recommend it as it's a big gamble but might work.
     
  9. Dec 17, 2010
    goodolboy71

    goodolboy71 Member

    SC
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    http://www.locknstitch.com/


    I have used these guys before a few years ago to fix the dreaded 53 numbered cummins diesel engine cracks more than once....use to be about 2-300 for a kit and it worked great. Don't know if I would drop that into a 258 when they can be had for just as cheap
     
  10. Dec 18, 2010
    Joe 69cj5

    Joe 69cj5 Going into Retirement

    Llano Ca.
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    I have welded a cat v 8 block in a Cat 988 loader after one of the rods knocked a hole about the size of your fist in the side of the block. I used nirod welding rod to weld it back together. But first you have to clean up every thing very clean and I ground down all the edges to make a small v grove between all the peaces. Then welded it up and ground it back down smooth then put one more pass on it. I had very good luck with it the motor ran for about 10,000 hours more when it was replaced. So I would say Its worth a try for sure.
     
  11. Dec 18, 2010
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Not trying to be overly negative about this, but a 258 is not a Cat V8. A 258 engine is neither rare nor particularly valuable, and I think it would be a mistake to try and repair cracks in such a common engine.

    A 232 block is the same as a 258 block, and 232s are very cheap or free when you find them. 258s are not far behind - someone just gave away a good 258 on NEOW. A few weeks earlier, someone sold a complete 4.0L for something like $80. These engines are around ... no need to make any heroic effort to save this one.
     
  12. Dec 18, 2010
    sterlclan

    sterlclan Member 2022 Sponsor

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    why not make some effort. its for part time use, good skill building job NOTHING to loose its broke now cant get worse time would be the only investment...well and some brazing or welding rod....
     
  13. Dec 18, 2010
    cookieman

    cookieman Member

    Colton,Calif
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    :iagree:
     
  14. Dec 18, 2010
    goodolboy71

    goodolboy71 Member

    SC
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    To weld cast iron and to do it right you will need a high nickel content consumable, and will need to do alot of pre and post weld heating to keep it from cracking, then some stress relieving via a needle scaler or ball peen hammer. It can be done.Between all the prep work,removing parts to be able to get to the area and weld comfortably ,etc to do it right....I just don't see it being worth it on a 258.
     
  15. Dec 18, 2010
    Long&Low

    Long&Low Active Member

    Geauga County, OH
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    I say give it a try, knowing full well it'll be a temporary fix.

    Then, find a '91 or newer HO 4.0ltr with fuel injection, and put that in. The 4.0 ltr HO is a better power plant, and only takes a few tweaks to put in.
     
  16. Dec 18, 2010
    djljeep

    djljeep Meandering Aimlessly

    Western Maine
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    right now i am really split. I agree with Tim and Patrick and Nick ect that the right way is put a different motor in it. right now i have the 73 motor on the stand next to the jeep that i could rebuild, I have an entire 93 4.0 in vehicle, and i am sure i could get another 258 reasonably cheap.

    The problem is i really want to free up that garage. I am going to chat with some friends in the near future to ask what they think, see if any of them offer a spare motor. for the time being i have other things to finish like body work and fenders and such. I think i will leave it alone, and leave the motor in so i can still move it around. I may weld/braze it just to save on coolant, but ultimately i think i will replace sometime after next fall.

    If i weld it, it will not be the ultimate fix. It will only be so it can move under its own power and if i have the rest of it done, it will be a spare jeep for jamboree in the fall.

    Thanks for the opinions guys.
    anybody have an opinion welding vs brazing? i have the torch setup and i have the stick welder and i have to buy consumable either way.
     
  17. Dec 18, 2010
    sterlclan

    sterlclan Member 2022 Sponsor

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    ive seen some pretty amazing brazing jobs ....thats my vote . old school is cool....
     
  18. Dec 18, 2010
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    I'd braze it.
     
  19. Dec 18, 2010
    djljeep

    djljeep Meandering Aimlessly

    Western Maine
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    any recommendations for brazing? I've brazed before, but on flat stock, not a cold, cast iron engine block. Same principle as welding it? lots of preheat, cool it slow? Make it real clean and clean out the crack?
     
  20. Dec 19, 2010
    ronar

    ronar New Member

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    I have welded a few blocks in my life too, mostly older ford flatheads. Where that one is cracked is both good and bad....the crack, if welded or brazed probably won't crack any further as it will stop at the freeze plugs. Bad part is also that the crack ends in the freeze plug hole and the plug itself may seep at the sides.
    Normally a cracked block is doomed but it just depends how much you want to spend and how much effort you want to put into it.
    You could pull it out, lay it on it's side, remove the freeze plugs, vee out the crack with a grinder and braze it up....or strip it down, send it to a welding/casting shop that specializes in that stuff. They will vee it out, stick it in an oven, weld it up and maybe it will work. I have had lots of industrial blocks and cyl heads welded like that.
    Or you could do what most advise.....buy a used engine locally or off the 'net somewhere and remember to keep the antifreeze checked. Good luck
     
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