Cracked block, cast iron.

[Fifelaker]

Google "Locknstitch" It may be something you can use.

 

[yomax4]

Perfect !

The lower right flange on the engine block of my 1947 Farmall Cub broke completely off. It's part of the attachment for the front end bolster that carries the axle and radiator. It's a known weak spot on that engine block and very often you'll find one cracked and sometimes completely broken like mine.

I was able to stick weld it with a stainless steel filler rod (Super Missile Rod, 1/8" dia rod, 90 amps, DC+). You need to control the temperature of the heat affected zone (HAZ) carefully to prevent cracks in the cast iron.

I don't have an oven large enough to heat the block to 1000-1200F as recommended for welding cast iron. So I used the alternative method--run short beads (1" long) and lay down successive beads using back stepping. I used an inexpensive infrared temperature measurement gun. Kept the peak temperature at or below 300F and let the parts cool to around 100F before running the next bead.

I peened the welds during cool down. I used an air chisel with a blunt rounded point initially. This seemed overkill so I changed to my pneumatic needle scaler to peen the beads. Seemed to work OK--no cracks in the welds or the cast iron.

It took probably 6 hours of work with a die grinder and steel burrs to bevel the edges and otherwise prepare the parts for welding. Had to rig up a fixture to keep the parts aligned during the welding process. The welding itself took about 4 days--I worked slowly and spent a lot of that time waiting for the parts to cool down and grinding the beads between runs. Now that I've done the job once, I probably could do it in half the time.

Good luck.

 

[caferacermike]

Shieldarc, Everlast, flusher, yomax, and fifelaker, thanks for the replies. Today's were a little more uplifting.


Shieldarc your reply is about 98% inline with what I had outlined to do, except with 309 wire. Only difference now is that I'm uncertain which wire to use. Props to my boy ChuckE2009 over on the YouTube. Every time my friend and I are about to weld something we now always shout out, "And remember everything I know about welding I learned from ChuckE". That kid is hilarious, and a badazz. In fact half of what he may be doing is dead wrong, but in the end it works. I like his style, insert youtube video herehttp://m.youtube.com/watch?v=Yopcz-IYDyQ Let me turn up the turbo in this thing and get it home, yeehaw.

So Shieldarc and flusher your replies helped solidify what the nutty kid was saying. Oh back about 22 years ago in auto shop we were forced to weld bare cast iron heads but we were able to control the outcomes much better in a full shop and with ovens and sand. Between the two of you, it sounds like a 1" pass isn't out of the question? I was thinking really slow and cold with just a tack weld of about 1/4" to 1/2".

Yomax, not sure what this powder is you speak of, but I'm about to google the snot out of it.

Fifelaker, in my thread in the Mitsu forum I spoke of pin stitching over there. Since if welding fails I can still pin stitch, locknstitch, insert other trade names here, that's my last resort and is still an option. The metal pushed out a little in one area and isn't a completely flush crack, that's why stitching was going to be my last option. I'll need to find a way to ever so slightly clean out the burrs so I can hammer it down flush.

 

[Shield Arc]

ChuckE / Lanse is a member here. He post every once in awhile.

309 stainless is really good for welding stainless to mild steel. flusher mentioned Super Missile Weld. That is basically 312 stainless. It is really good for welding cast steel.

 

[Arc weld]

I feel left out. Brazing and spray welding would both require a lot of heat. Eutectic has a special flux-core wire for welding cast iron using the cold method. If the block is pushed out, you have bigger problems and trying to beat it back with a hammer has a good possibility of making the problem worse, maybe a lot worse. The whole reason to use cast iron is because it doesn't deform and handles hot and cold cycling.

 

[skyhook]

Has this been beaten to death before? Sorry I typically stay over in my Mitsu/Satoh forum.

My lil Beaver got laid up over the winter months without much antifreeze in the mix and sure enough she popped. I basically bought a tractor to play with and gave it to a friend of mine to use on his land. Maintenance is his responsibility but he failed this time.

So what I have (at least I hope is the extent of the damage) is a block that has 2 cracks each about 3" long between the cylinders in the outside water jacket. Why the freeze plug failed to pop is another issue.

Research says strip the engine bare and either take it somewhere or pin stitch it. I may just pin stitch it but I'm afraid of drilling through the cylinders and making a bigger mess. I don't want to strip the engine as parts are as rare as hens teeth and I don't want to need gaskets, rings or bearings to go back together again.

I've been watching a few how to's and asking around a bit. I'm handy with the MIG and I can burn a rod if I have to. I don't know anything about stick welding other than crank up the heat until the rod melts. Lol. I have no idea what rod is what, just grab a grey one and go. I've got a nice 220v 180amp MIG and one method I've been interested in is swapping to a 307 stainless wire and basically making a 1/4" tack weld. Set down the torch and beat the snot out of the tack with a ball peen hammer and go do something else for 30 minutes. Allow the metal to completely cool and do it again, and repeat for days until finally closing up the crack.

I could also scrub the cracks clean, acid flux them, and brass braze them. Or I've considered some rods from Castaloy that claim to repair cast iron with a MAPP torch.

So what I'm asking is how would you do this considering that I feel stripping the engine, heating the case for a day, welding it and then cooling it for 2 days is out of the question. I could always Use JB WELD on them.

I've used this with "great" success, just make sure it's clean and dry.
Three years later and it was still holding, not really that much pressure there.

 

[Mark @ Everlast]

Brazing wouldn't take much heat...and it's possible with simple Oxy/acetylene. You don't have to heat the metal up to melting point. It is slower, but reliable for patching and some joining repairs. I never worry about cracking with this process since the bronze/brass is softer and can "stretch" as it cools. I supposed you could use MIG brazing (Si/Bronze) as well and do it a lot quicker.

 

[flusher]

Brazing wouldn't take much heat...and it's possible with simple Oxy/acetylene. You don't have to heat the metal up to melting point. It is slower, but reliable for patching and some joining repairs. I never worry about cracking with this process since the bronze/brass is softer and can "stretch" as it cools. I supposed you could use MIG brazing (Si/Bronze) as well and do it a lot quicker.

I thought about brazing that engine block flange on my Cub because of concerns about thermal stress cracks when welding on cast iron. But I punted since that flange carries at least half of the load of the front axle on that little tractor and that flange was completely broken off my block.

That said, there are threads on the FarmallCub.com site describing brazing cracked flanges on Cub engine blocks. Seems to work OK.

Most of the guys who do this repair rig up a brace (based on 5/8" dia Grade 8 threaded rod, usually) between the repaired front flange and the flange on the right rear of the block to give added protection. It's easy to crack that front flange if you hit a pot hole with the right front wheel while running your Cub at high speed through your hayfield or the woods.

 

[muddstopper]

On engine blocks, I have had good luck with regular mig wire and preheat. Drill a 1/8in hole at each end of the crack. Vee out the crack then preheat using a propane torch to 600*F. weld about 1/2in and peen with needle scaler. Then apply heat with torch and weld another 1/2in and peen. Repeat until weld is complete and then use the propane torch to even out the heated area and let cool. I have also used Nickel 99 stick rods on cast, but it seems I do more grinding than welding when using nickel. Have also had good luck with acet weld using bronze. Everytime I try the cold weld, it seems the weld cracks as it cools, but it could just be me.

 

[george md]

If you do any arc weld on the cast iron , you will NOT be able to drill for lacing plugs.

The rapid cooling will harden the area both in and around the weld ,it will eat drill

bits and destroy taps.

If your cracks are in a flat area ,leave the arc weld alone . There is no such thing

as cold welding with an arc , that arc is several thousand degrees and the area

around the weld sucks the heat out of the area rapidly causing the cast to harden.

Welding always makes some heat and being that cast is not ductile where is the

material going to come from when it cools, makes cracks.

From a guy that fixes cast , buy the kit from lock n stitch , it really works well.

george