Forum:
The farthest I've ever gotten into an engine in the past was to change spark plugs. About 8 months ago, though, I felt ambitious and I tore into my Rocky engine to replace the head gasket. The first time I simply replaced the gasket and sealed it all back up. The gasket only lasted about 2 months and it blew again.
I dug into it again and this time I took the head down and had it machined smooth, used another new gasket, torqued it all per the book, etc. A few weeks ago it blew again. It appears I need to have the block machined as well. Being a newcomer to this level of mechanical wizardry, I have this question. Can the block be machined while still in the vehicle (if I pull the heads and tow it down to the shop) or do I definitely have to remove the engine? Is there any other way of smoothing the block (putting some sort of high temp "goo" on it like JBWeld and clamping the head on while it dries, etc.)? If I have to remove the engine, how much more work is involved once I've already gotten past the point of removing the head?
Decking
Skimming the engine block is called decking, the engine will have to be removed and stripped, this is to prevent metal swarf from entering the engine. Some machine shops will claim to be able to deck the block with the engine in the vehicle, this was never successful when it was common practice years ago, the engine and machine always stuttered when cutting. Stuttering leaves a dimpled and pitted surface which is usually worse than it started, pull the engine and remove the risk of a bad finish, along with metal swarf entering the engine.
Remember, the amount of piston protrusion determines the thickness of the head gasket to maintain the correct compression ratio, the amount skimmed from the head also needs to be accounted for.