welding a freeze crack

You can't solder cast, but you can braze it . Done a lot of times with great sucess. If it is external, the motor does not need to be diss***embled, just sealed. General preheat with a weed burner, Thouroughly clean the crack and the adjoining area, v and clean again. contiue heating while brazing . Heat just enough for the extra fluxed rod to flow. Metal will be dull cherry red, cool slowly. Fill it with coolant of your choice and go.
Reminder- Brake cleaner produces deadly fumes when heated.

 

I got some rod I think will fix the problem from MARQURTTE 99% Nickel, M55768
FIR 1440-0425 From my NAPA store, About 43.00 for a 1lb pack, The first thing is to practice on an old head or some other piece of cast iron to get the feel of the Rod.update later on after I give it a try.

 

I've known people who had the Iron***e plugs done with no problems for years.

http://www.iron***e.com/

Remember to drain that water.

 

iron***es are the only way to go,i did it on a 35 ford flathead and it was perfect,go that route if you can

 

Thanks 61bone I may try that if the 99 rod dont work out but as it stands now I am going to wait till warm weather get here, I dont have any heat out in my shop its to hard to even get it up to 50 degrees in there now days. it 19 degrees here right now lol

 

I know a guy that fixes several freeze-cracked 409 blocks a year.
He cuts along the crack and cleans it out/opens the area.
He has cast iron rods, and Tig welds with them.
He welds for about an inch, then takes the pointed end of a chipping hammer and stress-relieves the fresh weld until it's cool enough to touch with his bare hand. Then he welds another inch and repeats until the crack is fully welded.

He does the whole thing cold--meaning he doesn't pre-heat the block.

He's had a lot of blocks live in every kind of environment and use this way, from trailer queens to drag cars. When the repair is done, it's VERY hard to see, due to the chipping hammer giving the repaired area a rough finish. Under a coat of paint, it virtually disappears.

-Brad