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  • welding cast iron heads

    i have a set of cast iron small block chevy heads that have a crack in the combustion chamber which is letting coolant into the cylinder. would it be ok for me to tig weld the crack shut? does anyone have any recomendations? i really dont want to replace the head, i am on a very tight budget and i already have a bunch of port work done on the head.

  • #2
    Re: welding cast iron heads

    No you can't tig or mig weld them, that will just make them crack more. Welding cast iron heads is very tricky and for a chevy probably not worth it even on a budget. To weld cast iron the head needs to be preheated then cooled very slowly so not many people do this anymore. Might be able to braze them depending where the crack is. What also might work for you is a product called stich-n-weld? can't remember the exact name Dave might know as they have run ads in Hot Rod from time to time. Anyway it's a process where you screw in a iron plug and it pulls the crack together, I've used it in the past but again it depends on the crack. You might be better off getting replacments from a cylinder head exchange.

    Good Luck, hope this helps some.
    There are very few people in this world who's opinion I value, you are not one of them.

    300 in 1999

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    • #3
      Re: welding cast iron heads

      i have heard that if you drill a hole at the ends of the crack it will prevent the crack from continuing when you weld it. but i dont know for sure

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      • #4
        Re: welding cast iron heads

        Welding iron is easy and there are many ways to make the repair you need. A metal spray process using O/A gas is the easiest for a novice using the torch from Maintenance Welding and their flux/nickle powder. You can easily arc weld it with any AC stick welding machine and Ni Rod. You can use specialty rod like Copperhead for the stick welder, makes this a piece of cake. You can also use iron fill rod and iron welding flux and a gas welding set-up, but this takes quite a bit of heat. You can pre-heat enough in a regular gas grill. I don't know why guys make such a big deal about welding iron, I've done it many times, and used all of the above metioned processes before.

        1. Clean adjacent area and "V" the crack deeply
        2. Pre-heat- makes welding easier and cracks less likely, even though lots of cast iron repairs can be done cold
        3. Weld
        4. Use carbide to dress the weld.

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        • #5
          Re: welding cast iron heads

          Originally posted by dulcich
          Welding iron is easy and there are many ways to make the repair you need. A metal spray process using O/A gas is the easiest for a novice using the torch from Maintenance Welding and their flux/nickle powder. You can easily arc weld it with any AC stick welding machine and Ni Rod. You can use specialty rod like Copperhead for the stick welder, makes this a piece of cake. You can also use iron fill rod and iron welding flux and a gas welding set-up, but this takes quite a bit of heat. You can pre-heat enough in a regular gas grill. I don't know why guys make such a big deal about welding iron, I've done it many times, and used all of the above metioned processes before.

          1. Clean adjacent area and "V" the crack deeply
          2. Pre-heat- makes welding easier and cracks less likely, even though lots of cast iron repairs can be done cold
          3. Weld
          4. Use carbide to dress the weld.

          Welding iron is not that difficult, if you're an experienced weldor, which you obviously are. It is a little more difficult for guys that can simply run a 6011 rod on some flat steel. The advce here is very good. If you understand the idea, try to weld it and see what happens. If the crack is in the combustion chamber as I understand here, I personally think it will be hard to fix. But either way, the head is broken. It will either fix or stay broken, I guess

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          • #6
            Re: welding cast iron heads

            When I worked for the Gov we had a block that cracked on a dyno engine (this is NOT good. The more hours an engine gets, the more valuable it is) and we called a pro welder in to fix it. After repeated tries, we had to re-block the motor (I spent a weekend doing it). This CAN work, or can go terribly wrong.

            If you PM NARIDER, he has a buddy who is one of the best cast-iron welders in the world. He does Duesenberg blocks and such that are irreplaceable. Todd can hook you up with this guy so you can get it done REALLY correctly.

            Dan

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            • #7
              Re: welding cast iron heads

              I have saved many ""numbers correct" iron heads that should have been junked. I have found for me the best way is to pin them. Irontite makes pins but the way I like the best is the lock-n-stitch method. You can go to www.locknstitch.com and see how its done. I also use a sealent on the threads of the pins that I get from from Casting Salvage Technolgies called CHEMSEAL. The best stuff I have ever used to seal.
              Doug Odom in big ditch

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              • #8
                Re: welding cast iron heads

                Thats some excellent and very useful info, Thanks for sharing.

                One of my favorite things about this place.

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                • #9
                  Re: welding cast iron heads

                  al mathon in long island was THE guy , I used to give his phone number out when I could , to do it right involves a furnace and all that
                  in welding class in mechanics school we welded cast iron , but the weld ends up harder than the rest of cast iron and cracks during expansion

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                  • #10
                    Re: welding cast iron heads

                    Originally posted by SpiderGearsMan
                    al mathon in long island was THE guy , I used to give his phone number out when I could , to do it right involves a furnace and all that
                    in welding class in mechanics school we welded cast iron , but the weld ends up harder than the rest of cast iron and cracks during expansion
                    Very true. And that's the hard part. Cast iron has to be heated in an oven before it's welded and the cooling has to be controled. It also has to be VERY clean. There isn't much room for error.

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                    • #11
                      Re: welding cast iron heads

                      maybe it is more trouble than it is worth

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                      • #12
                        Re: welding cast iron heads

                        I think you've reached the right conclusion. Some of the things overlooked by the pro weld group was your statment the you were on a tight budget. The welding was only part of the problem, you also had to take them off the engine, tear them down (bet you don't have the tools for that) Hot tank/degrease & bead blast depending on how old they are.
                        I know you didn't want to replace the heads but unless these were for a numbers matching car it's just a sb Chevy, as cheap as it gets to exchange or buy new.
                        There are very few people in this world who's opinion I value, you are not one of them.

                        300 in 1999

                        Comment


                        • #13
                          Re: welding cast iron heads

                          Originally posted by Dynoroom
                          What also might work for you is a product called stich-n-weld? can't remember the exact name Dave might know as they have run ads in Hot Rod from time to time. Anyway it's a process where you screw in a iron plug and it pulls the crack together, I've used it in the past but again it depends on the crack.
                          The product is called "Lock-N-Stitch", www.locknstitch.com. I fixed a cracked combustion chamber on my aluminum 427 SOHC heads, and the repair is holding fine at 800 HP. I would strongly recommend this product.

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                          • #14
                            Re: welding cast iron heads

                            Dulcich has a good article in the Engine Masters mag on the shelves right now about spray weldin iron. I've done it a few times (though not into coolant) and it seems to do very well.

                            I use iron-tite plugs all the time but the locknstitch are really a better design.

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                            • #15
                              Re: welding cast iron heads

                              The Henrob gas welder can do this operation also. Nice video at:

                              http://www.cut-like-plasma.com/info_video_library.htm

                              No personal experience with it but lots of guys on the HAMB like it.

                              Dave

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