I went and did it

425/409ER

Well Known Member
After my cracked 4122 block was sitting in the basement here for over 34 years my son and I got it out last weekend. I have decided to try and weld the darn thing since it's not worth much. Most of the places I called want over 5K to weld it then it would need to be machined also. I am either going with Muggy Weld 77 rod or I will do Belzona Super Metal, this is some good stuff. Since these are outside water jacket cracks my feeling is that the exhaust manifolds which are really close to that part of the block may cause problems with the Belzona. The epoxy really looks good and would hold IMO, but I think it would need a heat shield of some sort behind the manifolds. What have others done on this? I cannot afford a ton of money to fix it and like I said I am not out anything nor is the block worth a lot right now. Most I had in the engine when I bought it was $500, the 583 heads, intake and hi-po manifolds came with the engine so I don't care at this point.
 

Tom Kochtanek

Well Known Member
Supporting Member 12
I had some water jacket cracks welded up locally and I recall it cost me about $300 - $350 in labor at the local machine shop. Well worth it to save an otherwise good block.

Best, TomK
 

tripower

Well Known Member
Supporting Member 2
Have you looked at the stich repair? BSL409 did a repair thread on this process. I'll try to find it.
 

Jim Sullivan

Well Known Member
Supporting Member 10
We picked up a 409 out of an old truck some years ago. Both sides of the block were cracked in the usual place below the deck . After stripping and cleaning the block, while it was on the stand, we turned the block its's side and poured in the sealer, one side at a time While the sealer was soaking into the crack, I ran a propane torch back and forth, warming the cracked area. Did the other side the same way, then drilled and J B welded pins in the ends of the cracks. Then we slightly "v'd" the cracks on the outside of block and J B welded them. The engine has been running in the car for more than a few years now with no sign of leakage. We figured what do we have to lose, if it works than great, if it doesn't, we are only out some time and a little money for the sealer and epoxy.:dunno

p.s. We couldn't find anyone locally that would even attempt to weld the block.
 

IMBVSUR?

Well Known Member
Supporting Member 2
It has been awhile. however I looked at a block that Jack Gibbs had welded for him, I think in Washington. You could not tell it had been welded, it was that good, and I think it was about $300. I would call him and ask about it.
 

Ishiftem

Well Known Member
Supporting Member 2
I had small block in a camaros that had been welded. It was cracked the length of the block at the pan rail and below the deck with a big X connecting them. And it was both sides! Somebody had stick welded it poorly. Other than a drip or two, I drove it for two years like that. No wonder the car was cheap.
 

buildit

Well Known Member
Supporting Member 8
I've done twenty or so blocks with the stitching pins. They need to be angled against each other so that each pin partially intersects the previous one. This ties the two sides of the crack together. None of the blocks has given any trouble.
 

models916

Well Known Member
Supporting Member 7
Not much pressure in the water jacket. Liquid sealer works 99% of the time. But along with the water jacket cracks, lifter galley cracks will sometime come with them and you won't see them until it's too late. Pressure check that block to get all the cracks. Not sure if you can fix the lifter galley?
 

BSL409

Well Known Member
Supporting Member 6
Not much pressure in the water jacket. Liquid sealer works 99% of the time. But along with the water jacket cracks, lifter galley cracks will sometime come with them and you won't see them until it's too late. Pressure check that block to get all the cracks. Not sure if you can fix the lifter galley?
Yes you can even fix the lifter gallery with the lock & stich pins Carl just did a 09 a few months back in the lifter gallery
 

409envy

Well Known Member
Lock and stich on my 814 block... pressure tested and no leaks. That method gets my vote. Welding is good but there is still the possibility the crack may reoccure at the end of the weld. Plus the thermodynamics of welding cast iron can be tricky as you need to heat up the parent metal and keep it at temperature while you weld.
 

425/409ER

Well Known Member
Got my Muggy Weld rods this week, I almost chickened out on trying this on cast iron but I took a bad Vortec head ground a slot on the outside of the head down into the water jacket and proceeded to weld it. The stuff is truly amazing when you weld cast iron, no heating, no screwing around of any kind, just a very nice easy smooth weld. Looks like the I am going to try it on the 409 block sometime this week. Pictures to come when it's done.
 

425/409ER

Well Known Member
Well it's done, time for a pressure test. After welding I used A/B Epoxy to seal the block on the outside and I will used ceramic seal on it also. Here are some pics. I know the welds don't look the best buy after grinding the 1st ones down I added a second layer then used the epoxy, that stuff worked great, hard as a rock. I put some of the epoxy in an old cracked head then tried to bust it with a hammer, took some pretty good hits to bust it. Here is a picture of our other 409.
 

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Iowa 409 Guy

Well Seasoned Member
Supporting Member 15
Looks good, it ain't rocket science. Never heard of muggy rods, looks like a good way to go. I've stick and brazed welded lots of stuff over the years, aluminum, cast iron , steel, ect. Hundreds of pounds on build up. Most of the times it worked. Good job. Talk to other knowlegable people and follow directions. What diameter were the rods and what amp settings did you use?
 
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