Hi Dave,
I have had a bit of experience with projects like you face now. It's
daunting if you have never done it before, but it's not as bad as one
imagines. I would use a 3/32 stainless steel rod , type 308. It is a
small, high nickel rod that mixes with cast very well. You will never cut
it except with a stone, but for your needs it is suitable. It is a stick
rod so you will need a 220 welder. Use a heated piece of 1/4 inch thick
steel to get the amperage and puddle you like before going to the block. To
get the right heat setting turn the heat up until you are sure it is too
hot. People tend to set machines cool as they are afraid of burning a hole,
but if you are too cool, you get poor penetration. You're welding flat so
you can get away with much more heat which means better penetration. If you
are making a puddle of weld 1/2 inch in diameter or larger, I would start in
the center and really burn it in before moving away from center in a
Nautilus pattern. This rod is a dream to use, very smooth and tractable. The
block must be clean, scrubbed with a toothbrush full of acetone and blown
clear with the air hose. The cast has to be heated thoroughly and then some
before you make your puddle of metal on your hole (300+ degrees ). After
the weld, it must be cooled slowly; this is critical, the rod material and
block naturally cool at different rates so you have to control the cool
down. A guy could start the car after( if you suspect oil is penetrating
through the casting, do not run engine until after the weld, oil messes with
the welding process ) the welding and keep the weld area heated while the
car comes to operating temp. While the motor is warming , the rest of the
block and head are absorbing the heat from your weld area, don't let it,
keep the torch on the weld, though you don't have to keep it 300+ anymore.
Then shut the motor off covering the area welded with insulation of some
type, the more the better. After that first heat cycle, the block and
stainless become one and it will not crack. The cracks people experience
come from the two metals cooling at differing rates. When that happens, they
will pull away from each other, but don't stress, you'll be fine.
To the List:
Though I have had much success with the techniques described above, I am
always looking for a better, cheaper, or easier way to do anything...
Steve
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