How do i cut cast iron pipe grey

yes it can be done the following links can assist you also make sure drill bit[s] are sharp plenty of oil and rags Drilling and Tapping Cast Iron How to Drill Into Cast Iron Hunker Using Taps and Dies

Cast iron can Not be welded....

it appears that the 2WD drive LT's have the iron block while the 4WD trucks have the aluminum block

Do you mean broken off and stuck inside or broken off and fallen out? Broken off and fallen out in this case is a good thing. Sounds like you mean the exhaust is broken at the manifold but what isn't clear is which piece, the manifold or the exhaust pipe. The manifold is a part of the engine, the exhaust pipe is connected to the manifold via the flange you speak of so if it is broken (coming from the engine as a base point) before the flange you need to change the manifold (less likely - hardly ever breaks - usually made of cast iron or cast aluminium) or where they typically break just after the flange (exhaust pipes are notorious for rusting out here, you will need to replace the front exhaust pipe and donut (gasket within the flange). Due to the high heat in this area it is extremely common for the bolts holding the pipe to the manifold to not just be ceased to it (lube will probably do no good) but to actually weld (or forge if you will) themselves to the metal of the pipe, in which case you need to cut them out with a torch. A good mechanic can usually do this without damaging the manifold. That is why it is a good thing if they have broken off and fallen out, much easier to change then welded in bolts (which would not fall out). I say replace the front exhaust pipe because without knowing which year your protege is or if it has an after market exhaust I don't know for sure if it is a one piece system or more than one piece. If it is a one piece you will need to either change the whole thing or do some cutting and welding to piece a section in. In which case, I do not recommend cutting the new piece you purchase but if the old exhaust on the vehicle is in alright shape from the muffler back you may be able to section it off and just replace the front section. Piecing it together would require at least one more piece, one to contact the old pipe to the new which would also need to be welded on but this method can still be cheaper (most of the time). Anything other than a simple in/out replacement will require torches and obviously if the bolts are welded in it is not a simple in/out job.

The sensor is located on the exhaust system between where the cylinder ports enter the common manifold and the muffler. Sometimes they are on the cast iron manifold and sometimes they are on the exhaust pipe after the cast iron manifold.

Here's how to they're assembled - disassembly is the reverse:
http://www.mhsradiators.com/assets/19.asset

You'll need Adobe Reader to view the PDF file pointed to by this link.

The Radiator Spud Wrench below may prove useful, but it's a plumbing specialty tool that a licensed master plumber would have.

White smoke is burning antifreeze. You have more than likely blown a head gasket which is allowing coolant into the combustion chamber where is is being mixed with fuel and burnt.

head bolts for iron cast heads is 65. for aluminum heads, its between 45-50. 1.6 AE82 is iron cast.

Remove steering wheel ( phillips screws to remove horn, 19mm nut in centre), remove shrouds over column( phillips screws) , remove shroud above footwell ( the one that covers the fuse box etc , phillips screws again) undo the column and let it drop down ( 12mm head bolts up from underneath, directly below speedo )
You will see that the ignition switch/ steering lock is a grey casting held in by shiny bolts with no heads.
The easiest way to remove is to use a hacksaw and cut slots in the top of the bolts so that you can insert a flat bladed screwdriver and undo them ( this will involve cutting the casting as well, only cut enough to slot the bolts, don't cut the casting in half ! )
Some people prefer to use a pin punch and a hammer to tap the bolts around till the come loose, the choice is yours!
The loom is held into the lock mechanism by one phillips head bolt , undo this and remove the switch.
You are now ready to install your replacement lock.
Just repeat steps in reverse, make sure the lock part of the barrel sits neatly in the hole in the column before you tighten the bolts ( using the slots you cut earlier and a screwdriver.)
There may be slight differences as I am used to right hand drive corollas but my experience is that most things are generic.

Hey Joejil... I'm having the exact same problem that you had. I'd love a little help letting me know how you resolved the problem! I cut the bolt today to remove the alternator. Now to put it back together!