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  1. #1
    Jim S. is offline Hot Rolled
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    Default Is it worth trying to weld crack in engine block?

    I tackled the repair of a chronic coolant leak in my truck today, thinking it was leaking from freeze plugs under the manifold. I discovered a crack in the outer water jacket of the block about where the cylinder block merges into the crankcase skirt. It is in a place that is pretty accessible in the vehicle and can be ground out, drilled for holes to prevent crack propagation as well as allowing for moderate preheat without affecting other parts of the engine.

    All else being equal, what process would have best chance of success - nickel rod, braze or CI filler rod? I have done all three in the past (not on installed engines) but don't currently have any equipment so I will have to hire somebody with the talent.

    This is in a Dodge 225 CI slant six, other wise a good runner for my purposes and one I want to keep for a long while. The only cause I can determine for the crack is freezing but I certainly don't know when it might have occured.

    I'm thinking I have little to lose by trying a repair.....if it doesn't work I can get another engine but that's a lot more work and money.

    Any thoughts are welcome.

    Jim

  2. #2
    Mud's Avatar
    Mud
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    Honestly? Don't weld it, repair it with PC-7 Epoxy. I've done exactly that on a rather large break in a block, and it held for years. Clean it off as well as you can and smear on a 1/8" thick layer of PC-7.

  3. #3
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    johnoder is offline Diamond
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    Repaired an even old Mopar 392" Hemi Chrysler with the overlapping tapered and threaded plugs engine shops sell. You will need a bag of the plugs and the tapered tap made for them. These are the cat's meow for solid repairs in accessible areas. I have seen welded up blocks that froze again and even made a bigger mess that was ready for the scrap pile.

    John Oder

  4. #4
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    macona is offline Diamond
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    Look up metal stitching. Thats one possibility.

    Use some dye and a UV light to find the ends of the crack. It may go on further than you think.

    Devcon makes some epoxy based patches that you can use to seal up cracks. Might work here.

  5. #5
    huntinguy is offline Cast Iron
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    It all depends.

    I have never had one I welded come back at me. I have welded some that were incorrectly welded by someone else.

    First, macona is dead on. Most people weld to where they see the crack, not a plan. You have to weld to the end of the crack. Often times there is more than one crack and you have to fix those too. There must be no crack at the start or end of the weld. Heating and cooling are critical. One other part is contamination. If you can not guarantee there is no contamination in the weld, there is no weld.

    If you get someone who is good at welding blocks go for it. If not, don't weld it.

  6. #6
    torker is offline Cast Iron
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    Stock car guys up here...almost ALWAYS forget to drain the pure water out of their blocks at the end of the season. Come spring they fire up their hotrod only to find water spewing out the block.
    I've welded quite a few of them but they...being cheap SOB's figure out the JB weld would work rather than bringing it to me (thank god). Actually if they cleaned the cracked area right...the patches hold up really well. These motors have the crap run out of them in the hottest part of the summer and it seems to hold up. Some of these repairs are 6 or 7 years old now and still working.

  7. #7
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    enginebuilder is offline Stainless
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    I would try the stitching method myself if you have room to get a drill in there. "Lock n Stitch" is the brand of kit I had. Works well, because of the tapers on the plugs. Welding a freeze out sometimes makes a repairable block non repairable. Water seeps into the pores cast iron, and when it freezes, it can cause it to actually be spider webbed. You cant see it but, you will chase them little cracks around all over the place. If you can get all the oil and water off and OUT of the crack, the epoxy method works well to. I've drilled small holes diagonally off the crack to give the epoxy some "fingers" to hold tight to the block. Each one is different, but welding in the car is likely to result in you being an unhappy camper. YMMV
    Here's another tip for you cast iron guys, if you ever find yourself with a block with a big hole blown in the side, such as from spontaneous self dis-assembly, Mix your epoxy and completely saturate some steel wool with it and form it back into position. Makes a pretty tough repair.

    Jim

  8. #8
    Mark Leigh is offline Hot Rolled
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    I totally agree with engine builder on this. Lock N Stitch is located right here in Turlock , Calif---------- I have no doubt some cases welding can work, but the Lock N Stitch method is by far the best way to go. Tapered pins are old thinking, the reverse pitch thread the Gary patented is truly amazing. I have had several repairs done by them, and you can call them to find a authorized repair dealer in your area. 209-632-2345

    Even if you don't choose to call him go to the website, it's impressive what they can do with the system they have developed.
    www.locknstitch.com

  9. #9
    JunkyardJ's Avatar
    JunkyardJ is offline Titanium
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    Arrow JB weld!

    The method I've used for in vehicle quickie repairs like this is JB weld. You have to COMPLETELY drain the anitfreeze, but seen as how it's leaking where it is, you can let it drip out there. Wait until there's NO anitfreeze dripping out the crack in the block. Scrape off all the curd the best you can. Wirebrush the HOLY HECK out of the area using a die grinder until all the rust scale is gone and it looks CLEAN. Heat it with a propane torch until it burns all the oil goopus out of it, but be careful not to heat it excessively to make it crack it worse. basically you want to make sure all the oil that could kill the epoxy bond is gone. Then wirebrush it again with a DIFFERENT BRUSH to get rid of any ash residue. THis will make sure any gunk in the pores in the cast iron is burnt out. You want to make a square that's MUCH bigger than the crack. Take a piece of metal screen, and slather it with epoxy (JB weld). Slather the block with epoxy, and stick the screen to it. Take a putty knife, slather on more epoxy until you wind up with a smooth surface.

  10. #10
    Jim S. is offline Hot Rolled
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    Default Thanks for all the suggestions.....

    I appreciate all who have commented. I have not decided yet between lock n stitch or epoxy. I believe both will work but I'm waiting on a quote from lock n stitch on the materials needed for my job. I spoke with their tech rep and was impressed with their service. I'll post the results.

    Jim

  11. #11
    Mark Leigh is offline Hot Rolled
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    I'm not knocking anybody, but I'm glad you looked at Lock N Stitch. The guy that started it all , Gary Reed is a quite a story. He has a wall at the first bay of his repair shop with old poloroid pictures of repairs that go from something as big as a golf ball to castings that he repaired that are as big as a car, on site in factories all over the world. My story with him was 20 years ago. I had a Drag racing engine block that had burned through the deck of the block from one cylinder to the other, every engine building shop around said it was a 4000.00 piece of junk, I was told by a machinist who had heard of Lock N Stitch to try it. I went to Gary and he fixed it for 150.00 and it's still running down the dragstrip to this day. It was a perfect fix. Good luck to you.

  12. #12
    Mike C. is offline Diamond
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    Lots of good advice here. I'm the guy who usually says to braze, but not in this case. Success in a braze/weld/nickel repair here will require a preheat. If you take that engine out and strip it down to preheat it for welding, you can probably pick up another block cheaper and just swap the parts/rebuild. Even easier to just find a decent condition used engine and swap. Go with one of the non-thermal repairs and start looking for a replacement.

  13. #13
    Jim S. is offline Hot Rolled
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    Mark,
    Thanks for the additional info on Lock n Stitch. I'm planning to go that route but need a little more info from Gary. I've also received a number of other valid endorsements of their product and the wide variety of application they are suited for.

    BTW, his quote for material to fix a 8 inch crack was $144. That sounds reasonable to me although I could certainly get epoxy for less.

    This photo shows the crack before I begin the clean-up. It's actually 11 inches long, measuring from the inside edge of the two ribs. The wall thickness is about .200" and the crack is right at the bottom of the water jacket, not surprisingly. It actually appears to slant out and down so I will discuss with Gary whether the pins should follow the angle of the crack or be inserted at 90 degrees.

    Jim
    Attached Thumbnails Attached Thumbnails crack-slant-six-3-.jpg  

  14. #14
    JunkyardJ's Avatar
    JunkyardJ is offline Titanium
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    Exclamation OOOHhH, I dunno, that's a BIG crack!

    I think you're barking up the wrong tree here. I wouldn even attempt to patch that crack, given that you SEE 11", and it probably goes MUCH further, I think it's a waste of time. You're probably looking at $200 in materials, and if you don't get to the VERY ENDS, it will spread. Engines heat up, and cool down, which propagates cracks. I thought you were talking about a bitty split somewhere where the block was thin. That looks like the whole block was full of water, and allowed to freeze solid. You can get a running slant 6. or better yet, a 318, or better yet, a 360, and be MILES ahead. By the time you get done dicking with that mess, you could have the new motor in and running. I may be able to find you a GOOD running 318, WITH working trans for next to nothing. The ones without emissions controls and 2 barrel carbs got 18/gallon if you tuned them good (provided you don't have a 4.56 rear gear or something crazy).

  15. #15
    Mike C. is offline Diamond
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    I'm with J. An 11" crack is not a crack, that's a broken block. Use the $200 and effort to swap blocks.

  16. #16
    Mud's Avatar
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    I'd tack it together with 4 lock-n-stitch pins to keep it from moving around and smear it up with PC-7 or JB Weld, run the hell out of it and see if it leaks again. In the meantime shop for another motor or vehicle to replace it. If you find a good spare, the crack will never leak, isn't that how things work?

  17. #17
    JunkyardJ's Avatar
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    Wink If you're really lazy, you could stopleak it!!!

    You could do like some bungholes would and put a half dozen eggs in there, then sell it! Actually, my favorite recipe is to take the eggs, and that brown stopleak goop, and mix it together BEFORE you dump it in the radiator. A buddy of mine made it back from FLORIDA with a BLOWN HEAD GASKET like that! He drove it around for a few days before the head CRACKED because the head cracked because it plugged a steam hole in the deck. I couldn't beleive it, that was NUTZ!

  18. #18
    E. Bobicki is offline Cast Iron
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    Some cool repairs on the lock n stitch website, especially the marine generator repair. Good system, I had a crack in the head of an iron duke I rebuilt in highschool repaired with those.

  19. #19
    Avanti is offline Cast Iron
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    It is too bad you tore the motor down. All that you need to fix that crack is a can or maybe 2 of K&W Block and Head sealer. Accept no substitutes. I have seen it close up 1/4" holes in 10 minutes. I had an old for truck with a 400 motor in it that froze so badly that I had water coming out of multiple cracks in block and heads. I through in a can of K&W so that it would hold antifreeze so I could move it every 72 hours to keep the parking Nazis from towing it off until I could build another motor. Eventually I used it to go to the lumber yard about 6 blocks away. That was 10 years ago and that truck is still running around with that same motor. I thought it was hopeless. K&W is the only one that actually works. I have seen it fix cars with coolant leaks into the combustion chamber. It is PFM.

  20. #20
    Jim S. is offline Hot Rolled
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    Default Interim update....

    I have decided to go with Lock n stitch. I should have the bits in a day or so and will work on it as the weather allows over the weekend.

    I appreciate all the comments and suggestions. My decision to proceed with Lock in Stitch is based on:

    -my desire for a permanent fix, more or less. Would like the vehicle to be reliable for the foreseeable future and something I can unhesitatingly take on longer trips.

    -otherwise, the present engine runs well and has a good compression and is reliable. I really don't want to put in an unknown engine or go through a rebuild. Granted it is only a 225 CI 6 cyl engine, but for my purposes it is fine.

    -My desire for an in-vehicle repair. I am not equipped to easily pull the engine for external repairs or an engine swap. I am also working alone.

    -The expense for the Lock n Stitch bits (about $200) and the time to perform the repair are about the same it would take me to pull the present engine (rent/construct an engine hoist, etc.), let alone perform the repair or swap the engine.

    - my deisre to learn new techniques. I could fairly be called stubborn at times, but in this case, I would like to experience first hand a technique and process I have only heard about. I've read enough about Lock n Stitch, and talked to the inventor/developer (Gary Reed), to be convinced it is a viable solution even in this long crack (break?).

    I fully realize the repair may not work and I'll have to try another route but I think the process has enough chance to make the work and expense justifiable, in my case. IF I have to eventually try another route, I will likely remove and strip the engine down to the bare block so I can properly preheat to weld - and, yes, I am aware of all the challenges that presents.

    Again, I appreciate the comments and suggestions. To clarify, I don't dismiss the various epoxies or sealers (no eggs, thanks.....I want to keep this truck for another 100K + miles). But I want it reliable enough that I won't hesitate to let my wife use it to for a moderate road trip (to pick up some old iron, of course) without worrying while I'm out of country, for example.

    I'll take a few pictures as the repair progresses and post the results, whatever they are, realizing that full confidence in the repair will develop over considerable time.

    Jim

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