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Discussion Starter #1
Anyone ever successfully fix a crack like this? The crack is above the left oil galley plug in rear of block. It's a standard bore 400 block, otherwise I wouldn't even try to save it. I know there are probably a couple of Machinists on the board that have saw this before. Just wondered if anyone has ever had any luck fixing something like this.
 

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IIRC that is 1/8" NPT. If it was me I would stop drill the crack, drill and tap the galley hole for the next size up pipe thread, 1/4" NPT. Then I would either take or make a brass reducer bushing, tin it with soft solder (do the same for the hole as well) and thread it in.
Heat it it up so the solder flows then face it off flush to the block. Its not in a critical area stress wise so not worth going through the pain of Nickle welding it.
 

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I welded a bigger crack on a buddies 400 outside water jacket above oil pan rail. He sprayed 250 hp nitrous on it for a couple years, ran some low 9's in his Chevy Luv. Heated it up with a torch then welded it with a nickel rod after grinding/cleaning it. Have to cool it slow as in have the torch ready and get on it slowly backing off. If it cools too quick it will crack in front of you.

I have a real nice 400(#509 casting two bolt) that's been checked and shot peened that I just paid $350 for. I mic'd it and it's only got .004"-.005" wear so I'm going .020" on it.
 

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Discussion Starter #4 (Edited)
IIRC that is 1/8" NPT. If it was me I would stop drill the crack, drill and tap the galley hole for the next size up pipe thread, 1/4" NPT. Then I would either take or make a brass reducer bushing, tin it with soft solder (do the same for the hole as well) and thread it in.
Heat it it up so the solder flows then face it off flush to the block. Its not in a critical area stress wise so not worth going through the pain of Nickle welding it.
Thanks for the reply, I like that idea. I would have to make one because the crack runs almost as far back as the oil feed hole and the brass bushings that I have seen are fairly short. I have a lathe and I did make something similar from steel just to test the idea of a "sleeve". I'll try to post a pic of it. I was thinking a NFT just so it wouldnt spread the crack more? So, do you think brass would be better than steele? I like the idea of tinning the hole and the "plug/sleeve" with solder to seal the threads. I first thought maybe some type thread sealer but the solder would probly work better. Also it seems almost impossible to stop drill the hole because of space limitations for a drill unless I drill at angle or use some sort of really short 90 degree drill head.
 

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Discussion Starter #5
I welded a bigger crack on a buddies 400 outside water jacket above oil pan rail. He sprayed 250 hp nitrous on it for a couple years, ran some low 9's in his Chevy Luv. Heated it up with a torch then welded it with a nickel rod after grinding/cleaning it. Have to cool it slow as in have the torch ready and get on it slowly backing off. If it cools too quick it will crack in front of you.

I have a real nice 400(#509 casting two bolt) that's been checked and shot peened that I just paid $350 for. I mic'd it and it's only got .004"-.005" wear so I'm going .020" on it.
Thanks for the reply. Ive never really welded anything with a torch before. Is it hard to get the hang of for welding cast iron? I have welded quite a bit (not cast iron though) with MIG and Stick. Also pretty decent at soldering.
 

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Is that a small crack by the freeze plug too?
 

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1969 Nova . . 2dr . . Chino Valley,Az USA
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clean - it - up , maybe v it out & use some " Marine - Tex " on it.
The Marine Tex 'paste (putty) type stuff - (paste & hardner mix) .......... I've been using that stuff for years , ALL KINDS of "repairs".
My old can , even says " to repairs cracked engine blocks" -- right on the label.

Now, days they have a whole line of 'products' ....... but, I have only used their Marine - Tex putty. It's on My Nova Right NOW.
I patched a "Hole that I DRILLED in my gas tank ( I'm Stupid, I know)
but think about it - (not, that I'm stupid... we know that) ...............
but, about patching a gas tank ---- MOST Gas Tank Repair KITS , don't work , or, they work for awhile then go south. I used this stuff way back in the late 70's .. to patch my gas tank on my '53 International P/U , IT's STILL On There , and, still no LEAKS. My Nova gas tank .. patched back in 2009 --- Still NO Leaks.
I'm NOT THAT cheap , not for a fuel tank ... by any means ... But, I knew it would WORK , and it does.
When , we find a GOOD product , We Stick with it.
It Works & we pass that info along .... I've used it at Work .. we had a 10,000 dollar electric motor - that ran an 'acid pump' (and was critical for environmental purposes) .... the acid had eaten the bottom of that motor's oil containment area out ... They tried to weld the bottom of the motor - just to hold the oil, until they could order a replacement electric drive motor. The bottom was too thin too weld .... just several 'pin - holes' ........ So, I told them ... I had some "Stuff that would Work" ... and, it did (that motor , may still be in service, I'm NOT sure .. that Department laid-me-off , back in '08).......................................... but, I bet they are still Using "Marine - Tex" , today.

long rant , sorry ................. and, a Quart of Marine - Tex -- IS NOT Cheap , Like $ 80 a quart ( you use to be able to buy it in 'pints' , but I'm not sure, now)...... Think back too my 'Gas Tank' .. cost of a new tank ...... but, I knew it was "safe & works great" ... end of story !

Just KEEP IT Sealed UP Good ... I still have a can from several years back , and would use it if needed. Shelve life seems to last
( if sealed good) ..... Worth every penny , for everything type repairs .

my 2cents .... I think it's a great product .... (but , not cheap, again ... what's your motor worth ... ? ).

jim
 

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Stop drill it and look up a product known as Belzona. Not cheap, but will work fine. I used it on a cracked Harley case and it was flawless.
 
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