Frozen head Bolts

[tsubaki]

I've tried each of the methods described above and haven't been able to make any distinction as to what's best.
Seems each bolt has it's own preference as to when it wants to come out.
As always I'm amazed and relieved when (if) it works and not surprised of a bad outcome.

[Kracker Jack]

This thread is giving me flashbacks of my old 200 yammy that was on my 24 seaox!! what a nightmare that motor was to work on. She was a corrosion magnet. sorry I cant help all methods that I would use has been mentioned

[phatdaddy]

i've had slightly better results with the maps (yellow bottle) gas over the standard propane. it's a hotter flame, but be careful, aluminum goes from ok to uh oh very fast.

[BRIELLY]

I hit it with the mapp gas today...Good news/bad news. The top bolt came out and I thought the next one was loosening but unfortuately it broke flush with the block. I guess its time to bust out the left handed drill bits and hope for the best. If it doesn't work itself out I'll robably have to try a helicoil.

[phatdaddy]

been there, done that....
except this is where i usually break off the e z out down in there.

[BRIELLY]

I don't think I will chance the ez out. Ive read too many horror stories of them breaking and being impossible to drill out. I'm hoping to just keep drilling with the left hand bit until it breaks free. If i have to take a dremel and slowly grind it away then thats what will have to be done. I may drill a small hole into the block at a 90 degree angle so I can shoot some penetrating fluid in to where the threads are to help it along.

[BRIELLY]

When I got back to the boat today i realized I was looking at the wrong area. The bolt was actually broken half an inch inside the block but luckily it was a clean, flat break. I center punched it and started with the left hand bits. I also drilled a small hole into the block at a 90 degree angle to the threads to get more penetrating fluid in there. The drilling wasn't go very strait and i almost gave up. Too much more off center and I would have drilled into the water jacket and it would have been game over. I straightened the hole with my dremel and went to the largest size bit. A few seconds and that sucker came right out. I did mess up some of the threads so I'll get some epoxy thread repair just to be safe. You gotta love the left hand drill bit! Thanks to everyone for their help. Hopefully there will be no more surprises on this project.