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Old 10-09-2002, 03:16 AM
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Post cracked block

it would be greatly appreciated if anyone can tell me how to go about fixing my olds 394, if
possible. the crack that i found,(after the
rebuild) is located in the upper part of bolt hole
where the rear main cap bolts to the block. is it
possible that this can be fixed? have to much invested in it to trash-out. would be willing to
part engine out if necessary.

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Old 10-09-2002, 04:58 AM
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There is really no way to repair it yourself, and I only know of one method that really works for repairing cast iron and most machine shops do dont use it. Some say it can be welded with a nickel rod, but this will generally crack again in the future.

The method that I have seen that works correctly involves a powder metal torch. What is done is the crack is comletely ground out and then the crack is filled with new material using a torch that heats the entire area and then powdered metal is blown through the torch to fill the crack. Like I said however, I have never talked to a machine shop that knew of this method. I learned about it in school in industrial metals course.

The problem with welding cast iron, is that the high carbon contect of black cast iron used in engine blocks causes a crystaline structure that is unstable. By using the torch method you are replacing the cast iron with new cast iron and as it cools it will settle into a stable crystaline structure.

You could possibley get the torch yourself and do the repair, and have the block remachined. You can buy the torch attatchement that works on a standard victor for about $300. I, however, dont know a contact to get one.

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Old 10-09-2002, 05:50 AM
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Turbo is very right about "unstable". Unless you have an oven, and many hours of experience, it will crack worse as it cools. I've tried and seen tried, many attempts to repair blocks. It's beyond the scope of most people. Do a search for cast repair. I think there is an outfit in Ohio that uses the torch-powder method.
Sorry about your block. I have a few just like it in my scrap pile too.
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