So around 1:00 AM I went out to the garage. Over the past week the weather has been more typical for early August in the midwest--hot and humid--so if I did anything at all in the garage it was after dark with the doors closed. This limits the amount of sweating I have to do.
My main aim, last night, was to remove the piston rings and de-carbon the pistons. There are only a few ways to accomplish the latter, particularly when it comes to removing the carbon from the piston ring grooves.
Option 1: sandblast. Not an option for me as I have neither a sandblasting cabinet nor a compressor with enough guts to run a sandblaster for more than a few seconds at at time. (Obviously you wouldn't use sand on pistons; you'd use something a lot less aggressive to avoid profiling the metal. But "sandblast" is easier to write than "media blast" and it means approximately the same thing.) This cleans the ring grooves as well as the other piston surfaces.
Option 2: wire wheel. This is the method I used, for two reasons. First, I have a bench grinder with a wire wheel. Second, the wire wheel doesn't even mar the pistons; it strips the carbon off quite nicely but doesn't profile the metal. Problem: it doesn't clean the ring grooves.
Option 3: hot tank. This is the best way if you have access to the $10,000 machine. I don't; enough said. It gets everything totally clean, "like-new" clean, and it's about as much work as loading and unloading a dishwasher, albeit with heavy metal parts rather than dishes. (I have no idea what a hot tank would do to dishes. Probably clean them and forever make the food placed on them taste like solvent.)
Of course, since I wire-wheeled my pistons, I had to go back and manually de-carbon the ring grooves. There are two ways: first is to buy a special ring groove cleaning tool; this makes the process relatively quick and painless.
The second is to take a piece of piston ring and scrape the carbon out; that's what I did. It is neither "quick" nor "painless" but it has the advantage of being approximately "free".
It took about an hour, and made my right hand and left shoulder (the bum one) hurt quite a bit. When I got to the last piston I tried sharpening the bit of piston ring to make gouging out the carbon easier, and found that I had given it the ability to shave metal from the ring groove, so I flipped it over and used the other side.
But the pistons are clean. I managed to abrade away a small patch of skin on my right index finger in the process, but they're clean.
Next I turned my attention to the cylinder head; I had to remove all traces of the old gaskets from it. I got the intake and head gasket faces clean, but the exhaust gasket face is being stubborn. This makes sense, considering how much heat the gasket endures, but the head is aluminum and that limits how hard I can scrape the surface.
Still, little by little I am zeroing in on having everything ready to go back together. I could reassemble the bottom end right now if I really wanted to, but I want to make sure everything is clean first--all wire-wheeling and painting done--so that I need only wipe things down with clean rags before laying them out on a clean table.
Cleanliness is the key to engine longevity; keeping everything clean during the rebuild ensures less guck in the engine, which means less wear (or worse) during operation. Ideally you want the engine parts to have nothing on them but clean oil when you put them together. For the most parts, contaminants will be flushed into the oil pan and filtered but why let them get that far?
So I've still got some cleaning to do. The oil pan is filthy; it's next, once I get a halfway decent day on which to hose it down with Dawn and water.
The oil pan's bottom was coated with sludge, and I found that a bit dismaying. I changed the oil in that engine regularly, and every other part of the thing showed it; that sludge should not have been there.
Well, it won't be there much longer.
It's hard to believe it's now been more than two weeks since I started this little project.