Posted by Sherman in Idaho [24.32.202.166] on Tuesday, July 16, 2013 at 11:57:56 :
In Reply to: Sounds like prying is only thing left. posted by Sterling [99.58.180.94] on Tuesday, July 16, 2013 at 11:32:42 :
It can't hurt to soak the gasket area and bolt/stud holes with penetrating oil or ATF and let it set a couple days before banging and prying on it. I don't think you'll break the manifold by driving putty knives and scrapers under the edges. Just don't start beating on it with a double-jack or jamming a rock bar under the edge and prying. Once you get it off, you'll probably want to get the manifold ASSEMBLY (intake and exhaust together) ground flat by a machine shop. If the block is pitted, that's tough to deal with, but mine have turned out okay if I clean them up thoroughly (a wire wheel on an angle grinder is great if you can get all the studs out), and if there are still pits, using some red RTV on the block side of the gasket. If you replace the studs, I believe some go into the water jacket so they need sealer on them.
With your headless bolts, your next task will be to get them out of the block without breaking them off in the block. The first thing is to heat them red-hot next to the block (don't point the torch right at the block, though) and let them cool. You can put some wax on them when they cool off to where they'll melt the wax without burning it. With luck, you should be able to grab them with vise-grips and unscrew them at that point. Otherwise, weld a nut on top and try an impact wrench on its lightest setting, maybe going in both directions. The idea is to get some vibration in there that will help break the rust loose. When putting it all back together, try to get the right (are) conical washers and special lock nuts with the tapered slotted end that goes down into the washer. A lot of them have been put back together with regular nuts and regular lock washers over the years, but they tend to work loose.