I recently picked up a complete 392 literally out of a barn laying in the dirt. I picked this up to put together a good little street motor to sell. After getting the exhaust off I discovered an old weld on the outside of the block Below the Deck and above the freeze plugs. Common place apparently, its LONG really LONG about 13" total. I ground the weld flat with the iron surface of the block and put some water in the block up past the welds. 2 spots had a slow leak. (see pictures) The Block was cleaned and Magg'd (go pick it up this friday) The shop said all the structural stuff is good, main webbing, lifter galley, deck, etc. A friend of mine (A Journeyman Welder) Has welded cast Iron in the past and volunteered his sunday to come prep and weld the crack . I am the Gopher only in this part of the project. Here is his plan. A: Grind out the old weld and trench the crack. B: Drill holes @ the end of the Cracks C: Pre Heat iron and Tigweld with Chromoly Rod N-90 rod? (excuse me if I am way off on the rod name) D: Controlled cool down with Sand bags to prevent additional cracking. The Way I see it It cannot be messed up anymore than it is already. I was searching for an additional plan in addition to the welding. here is where I could use some old tried and true methods...... My Idea was remembering the old technique of lining an old Fuel tank with that liquid Epoxy. it sealed the tank and encased any crud on the tank. Has anyone Used something along those lines I could poor into the block and rotate it on the stand, with the weld side down to completely coat that side of the inside of the block to seal it from the inside? I figure this would be an additional sealer (hoping the weld holds water) that seals the block from the inside. with tolerance to heat, antifreeze etc. Worse case It gets hard block and gets ***embled as a race only Motor. Thanks for any recommendations to help save this Ol HEMI.
You can put tank seal I a block but the block needs to be completely clean and scale free. You can also just use water gl*** if all it has is pin holes and it will be fine for the duration. I have been welding for nearly 50 years and have never ever seen a TIG weld hold on cast iron, and sand bagging it is an old wives' tale. You stick weld cast iron and relieve it with a needle chipper or beat the hell out of it with a chip hammer if you don't have a needle chipper. Nickel rod is what the old timers use but there are some newer allows that are good as well. no you don't want to cool it with water like any other welding process but air cooling won't hurt it. No offense intended to your journeyman friend.
None taken! Im an engine and ch***is guy The chipper is like peening it to relieve stress correct? The Welding supply shop said the rods are 90% nickel for cast iron. They started off with showing me some arc welding sticks and told me these 3/32" are lust like the arc rods minus the flux. The Block is coming directly from the machine shop after being cleaned and Magnafluxed. I know it wont be as nice as the old days when they could used the acid tanks to clean them. they used to look like brand new cast iron back then. guess that means I am getting old! Thanks for the info!
Yep it is even called peening, not the same as shot peening but most weld shops are not set up to shot peen. They have outlawed hot tanks here in good old misery, but I know where there is a machine shop clear to hell and gone out in the country that builds pullin tractor motors and they still got a real hot tank. I have seen an old block with gawd knows how many coats of paint on it come out clean as a whistle.
Feel free to laugh at me,but the kind of little seeps through a weld you are talking about have responded well for me to a product called "smooth on".I learned about it from Dad and he used it on seepy cast iron repairs all the time.PNB a not very easy but effective method of repairing big castings is this: V out the crack and stop drill both ends-smallest holes possible. Dig a hole bigger than the casting and start a charcoal fire in it,let it burn down to a nice bed of coals.Put the casting in it and cover it with coals,let sit for at least an hour-long enough to get the casting hot all the way through.Brush the coals off the casting and braze or if you must ,weld the crack.Bury the casting in coals and go away.When the fire is out and everything cooled down you will have a good repair that will hold.I grew up watching Dad do that-I usually had to dig the holes- and I never saw him lose a casting.
Seen it done. it works. Drilling the ends of the cracks is as important a part of the process as any. I used to work with a guy in a factory that brazed cast all the time and on things like the head of a 20 ton press with good success. I lean toward ni rod and a stick welder because I am lazy. Even with that method it never hurts to pre heat that spreads the heat over a larger area.
Welded cast iron a long time ago. I had a coal fired furnace that the part went into till red, then pulled out to weld, never letting it go dark by reheating as needed. After I was done, the part went back into the furnace, the fire was "banked" and let to burn out on its own over a couple hours... Pretty good results.. The trick, in my opinion, is to have the whole block hot, and to keep heat in it while its being welded ( rose bud). The cool down time is critical: hours, not minutes.
Eutectic 2-24 [1/16] and 2-25 [1/8] is rod for heli-arc cast iron; I don't know if brand still around but maybe can cross to another...I have used this rod and the instructions are (1) to keep casting temp below 100° by welding about an 1/2 inch, peening and letting it cool..Benefit is minimal to no warpage and don't have to work/weld in heat..I set up a small electric fan [muffin] to cool down in between beads...(2) Preheat to 375° and keep above while welding; short beads and peening..pain to pre-heat and work/weld in it..Either way V-out and hole drill ends of crack [if you can find the end]..
i had a freeze crack a bad one on a 327 once welded it with nickel rod dripped very little the I quit rusted shut or something ran it for years never bothered
Tig weld it with 309 Stainless works great . Keep it about 250 dg. Short welds and pean to stress relieve. Do not use for thread repair because it's extremely hard to Drill & Tap. Drill stop holes at the end of crack. Good Luck Frank
Warm it up and stick weld with high nickel cast rod . Could have a new alloy sense the last time I did it . Drilling and cold weld is the answer , I have done many castings this way , time consuming but as go as new when repaired . I have used the pinning method on casting that held pressure . Natural Gas pipeline compressors . Mega pressure on the repaired crack . 850 psig !
Pre heat and stick weld. Welding an 18th century water mill casting I forgot about the pre heating bit and I picked it up to check the weld. Didn't have a glove on my mask hand (this was in the 80's) and got a blister four inches across. The weld's still there out in all weather probably with some of my DNA still attached.
I would not stray too far from Lincoln's recommendations. http://www.lincolnelectric.com/en-us/support/welding-how-to/Pages/welding-cast-iron-detail.aspx
I have not personally used this stuff, but my dad has and swears by it. Its called MarineTex. He has used it in the past himself to repair a cracked head and pump and has also seen it used to repair cracks in the valve area in heads and rads. They used to use it in the shipyards in Vancouver back in the day maybe you could use it to "seal" off the existing weld thats there and not risk the chance of further damage to the block with any more welding as it has already been subject to a welding process in that area once before?
I did a lot of field repairs on heavy equipment, no furnace and no time to pull down and go looking for one. When you got your equipment on grade time is money. I welded up a cat on the Mojave after the crew was done for the day, so sundown and frigid. Motor was warm scarfed it out welded it and it was still holding well when I left the company. There are ideal situations and then there are situations where the work has to be done. If I want something done and can't do it myself I will take a maintenance technician every time.
FWIW, I had a cracked cast well pump housing repaired some years ago. IIRC, the guy stick welded it using stainless rod. I wasn't there for the complete process, but it never leaked. 20/50 psi @ many cycles for many years.
Call these guys and pick their brain, it's all they do. http://www.accastingrebuilders.com/experience.html
The crack you are dealing with sounds like it is from the block freezing. The stress is now gone and if you don't freeze it again, there won't be the stress on it in the future. That makes it an easy repair. Primarily you need to fill a hole. Grind it out and stick weld it with a nickel rod. Peen it as Porkn****** explained. You will be good to go. Or you can make this into brain surgery. Neal
YEP!! I was fortunate that the parts brought to me were not large and easy to handle. Totally agree that when you're in the field and time is money, you do what you have to do. In reading the posted info from Lincoln, either method will work, but you have to follow through for best results.
My other hobby is restoring hit/miss farm engines. Cracks in the head and block are commonplace and I've successfully repaired more than a few. Most of the advice given here is spot-on. To summarize, based on my experience: 1) Clean, clean, clean. Carb clean, acetone. Blow dry with air. **** bubbling up from dirty metal with give you a porous weld that will leak 2) Drill the crack at both ends. This stops the crack from travelling 3) V out the crack so that the weld gets good penetration and does not just sit on top of the casting. 4) Heat with a torch to burn off any oil. Not glowing hot, maybe 500 - 600 degrees. Let it cool. Oil in the cast will contaminate your weld. 5) I use a mig welder with cast iron/nickel wire. You can get it through McMaster-Carr 6) Right before welding, gently pre-heat a larger area 7) Weld with the nickel wire 8) IMMEDIATELY after welding, while the metal is still glowing if possible, beat on the weld with a ball peen hammer or a welding chipping hammer. You want to push the weld into the block to prevent cracking along the edges as the weld cools. Keep on hitting it until the metal cools, maybe 3-5 mins. (this part is very important and well do***ented in the Lincoln Welding School book). You should be good to go. Good luck. Chris
I have seen these cracks tackled many different ways. Lock-N-s***ch, braze, JB weld etc. I believe BARSTEEL & PORK&****** are very much on target here. Do the repair BEFORE any machine work as the block can move a little if welded. I used to work at a heat treating shop and had access to large furnaces. Most cities have a heat treating business, if you can strike a deal to preheat and weld at their shop the ideal way is to preheat the entire block. weld, peen, reheat & repeat til done. Put it back in the furnace to soak a few hours and leave the circulating fan on shut the heat off and allow to slowly cool over night. Its not easy as a m*** of iron that size at 1100 + degrees is not fun to be next to while wearing heat protective gear. Yeah some will say way over kill. The satisfaction of a job well done & piece of mind will outlast a failed repair. I have done some extreme casting repairs with this method and with the correct joint prep, rod and technique it will last. A heavy descaler can reproduce the cast appearance to hide the repair as well. Best of luck & saving that block is a good thing. Dave
If your welder is a good Tig hand he will be able to repair that block to 100% better than new condition, I know I could. There would be no extra sealant required inside either. The key is in properly preparing the block, grinding away the old weld and cleaning. No drilling of holes or any of that is required. Another key is to use the proper welding rod. The best that I have ever used for this purpose is UTP -GFeC-1-GO Welding rod used for oxy-acetylene hot welding of cast iron when a weld of the same color and structure is required. Use UTP flux #5. That is UTP's description. The rods are about 18" long, around 3/16 in diameter and look like grey cast iron. The best news, they make awesome cast iron welds with DC electrode negative Tig with no flux. This stuff is nothing short of amazing and will do perfect Tig weld repairs on cast iron. I demo this to my students all the time. A good pre heat and a little post weld heating followed by a slow cool under a pile of welding blankets will do the trick. I have done lots of this type of work with this product using no furnace and no peening etc. External block cracks in the water jackets are the easiest to fix and that engine does not need to meet the race block fate. By the way, yes the repair should be done before machining.
After reading all the replies (lots of knowledge on the HAMB), I'm confident the block can be repaired, however, my concern is that you're building this engine to sell and wonder how much of an issue the fresh repair will be with prospective buyers and the end selling price? Sure you don't have a HAMB worthy project that could use a 392?
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