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Thread: Welding cracked engine block.
03-19-2005, 06:47 PM #1
,I am restoring a 1950s tractor with a Perkins engine .I have found a crack in the water jacket today due to frost damage that I need to weld .It is on the section between the liner housing and the outer jacket on the cylinder head face . Any advice on preheating / peening procedure and rod selection would be greatly appreciated,.
03-19-2005, 07:22 PM #2
My suggestion is DON'T WELD CAST IRON.
"Metal stitching" is a great way to repair iron castings, but generally not a do-it-yourself project.
Brazing with an oxy-fuel torch would be my first choice of a do-it-myself fix, otherwise a metal-filled epoxy.
In either case, I'd drill the ends of the crack to halt additional spreading and V-groove along the crack.
03-19-2005, 09:02 PM #3
I have not done any myself, but what I know I offer.
Nickle rod is supposedly very good, attraks to cast iron like a magnet I hear. I have seen some old flat head engines repaired with it and it lasted for ever. Side of block type cracks.
Drill the ends of the crack to prevent the crack from spreading.
For cast iron pullies, the shop I took them to preheated them in an oven for even heat expansion. Worked great.
The other shop I had tried before destroyed a couple by trying to weld them without preheating them. Not sure how they tried welding them.
I saw a shop instructer once take a 2" crack and run it to about a 5" crack in the side of a block. Did not know what he was doing and everytime he brazed the crack it spread another little bit. He did not drill the crack ends nor did he pre-heat the block well. All he did was run the torch around the crack a few times trying to heat the area then braze. Also his brazing cracked back off too. I don't think he V grooved, just tried to stick brass to onto the blocks outside.
What a doorknob! (as he would say)
I would look into it alot before taking a chance on ruining the engine.
I know another way that the crack repairs where once done, not sure what it was called, maybe it was stitching? Drill the ends of the cracks, tap them and screw in bolts. Drill into about half the bolt you just installed and the crack, tap that hole and install the bolt. Repeat as many times as needed untill done. Machine surface as needed.
Not sure, I think each time you add a new bolt you grind the head off before doing the next drilling. I know it worked, but I never did it myself. As far as sealing the threaded bolts as installed to prevent seeping later I don't know if anything was used or not.
In the old days they did not have epoxy as we have now, but they still fixed stuff. Today we have epoxy but everything is thrown away. I don't have any idea if epoxy would work for this or not, it might?
I used to hang out with great old timers when I was younger and learned alot of what they had done, but never did it myself so I have forgot alot too.
03-19-2005, 09:22 PM #4
"I know another way that the crack repairs where once done, not sure what it was called, maybe it was stitching? Drill the ends of the cracks, tap them and screw in bolts. Drill into about half the bolt you just installed and the crack, tap that hole and install the bolt. Repeat as many times as needed untill done. Machine surface as needed. "
These days you can get tapered taps and tapered threaded cast iron plugs for doing the above. Worked for a side of block crack on a blown 392 hemi I built. The idea with the cast iron plugs is you just screw them in until they naturally snap off.
03-19-2005, 09:35 PM #5
I would suggest welding the block. Cast rods are alot better today then years ago. Look at UTP or Castolin eutectic rods. I weld for a living so not welding it is unthinkable. I only bring the weldment to 100F and keep my interpass temperature below 300F. Scott.
03-19-2005, 09:58 PM #6
I don't weld a lot of cast any more (I prefer machining to welding ), but welding a block is a very difficult job. For one thing, oil and antifreeze contaminate the metal. This makes it extremely difficult to get a leak free weld. The only surefire method I know of to drive these types of impurities out is to preheat the entire casting....I dunno, maybe 500 or 600 degrees, then heat the cracked area up to a dull red heat, at which time, the impurities will depart that area. Then, you have half a chance to get a good weld. Weld it while its hot.
I avoid the pure nickel rods, and have had much better success with the ferro nickel rods, such as UTP 85 FN. This rod will go on much faster than the high nickel rod, but is still peenable and machinable, should it be required. The speed of deposit is important, because it creates less heat stress. The peening must be done while the weld puddle is still red.
I don't envy you having this job. It can be very frustrating. From personal experience, I've found that the "cold welding techniques" just take 4 or 5 times longer to find out what the results will be. Preheat, preheat, preheat. Big torch, lots of gas, slow cooldown.
That's my 2 cents, not as a journeyman welder, but just a guy who has tried a few things.
03-19-2005, 10:46 PM #7
Your answers can be found at the welding school..
Lincoln also had a hand in a process to weld cast iron with out a welder..
The company that had it was located in Cleveland Ohio..
saw them repair a ships engine...with the the process.. It was
similar to the way rail track was welded in the field.. but different.. John Paul
03-19-2005, 11:13 PM #8
03-20-2005, 09:56 AM #9
pin or stitch it for sure
03-20-2005, 11:05 AM #10
I used to work for a company called United Welding Processes in Mississauga Ont. that did nothing but repair castings. For a water jacket crack we would typically used the tapered cast iron plugs. I think these went by the name "Sea-tite" or something similar. These would be installed in an overlapping fashing with one plug being drilled, tapped and installed and then the following plug would be drilled on the point where the edge of the previous plug intersected the crack. When finished the plugs were all ground down to slightly above the original surface and peened out. We then applioed wicking loctite to seal any porosities. These repairs were tested to 80 psi. I would magnaflux the area to make sure that there are no other cracks that can't be seen. Usually the ice pushes out an area of the jacket rather than just cracking it. When that happens you have to weld in a patch. For that repair we used a steel patch, welded it in with UTP 8(?) nickel rod and peened it out thoroughly to eliminate stresses. The weld must be made in very short beads, cooling between each bead and peening. Good luck with your repair. Glenn.
03-20-2005, 02:45 PM #11
I have used Lock & Stitch products with excelent results, here is a link to their web site
Their special taps, and special lock bolts actually pull the metal back together, on thicker cast iron sections they have a metal cross lock that is used along with the lock bolts.
03-20-2005, 02:57 PM #12jfsmith Guest
I asked a friend on mine and he repaired a cast iron machine base with the LNS method. He said the engine on the other hand is a work of love to do it and it can be done, but requires a lot of skill and the right rods. Plus maybe a complete preheat of the block.
Me, I would send it out.
03-20-2005, 03:26 PM #13
Jim, I used to weld quite a few cracked engine blocks, mostly for oval track guys who always forget to drain the water from their engines before freeze up. One of the cheap buggers didn't like how much I charged so he used JB weld on the block. Said he drilled the ends of the crack and actually pried the crack apart a bit to force more epoxy in there. It worked so well that I haven't had one block from them since. They all use JB now. The first guy, was 4 years ago and he's still using the same block. Something to think about.
03-20-2005, 04:31 PM #14
I have had amazing results with epoxy steel ( JB weld and such. For a water jacket repair it should be no problem. The important thing is to CLEAN, CLEAN, CLEAN, before aplying it. It would be a good idea to grind a "V" and drill the ends. Also make sure you mix it really well. When you think you have kneeded it enough go some more.
03-20-2005, 06:53 PM #15
If you decide not to weld. Then use "Devcon". I have used it extensivly on cracked engine blocks and vertical turbine intermediates ( outer casing part that impeller of vertical pumps works in). Devcon is available for bronze, aluminum, steel, or cast iron. Just V-groove the crack, fill, and let sit 24 hours. Then smooth surface and no one will ever know it was ever cracked.