I've only tried the oven cleaner idea a couple of times, and didn't much care for the darker reult myself. As near as I can tell, there's an oxidizing reaction going on that is breaking down soils-grime-dirt - call it what you will - into microscopic particles and embedding it in the pores of the metal.
The reason I like brake cleaner, aside from the aroma
, is that it breaks down the soils and oils and leaves the metal alone.
Hands down, bead blasting is the *big gun* of cleaning processes. But likewise, you don't use a .458 Weatherby Magnum on a duck unless you want the feathers to come down in the next county.
Beading is fine for inner cases, jugs, heads, inner cam covers - anything that isn't normally polished or chromed from the factory. It will leave clean metal behind, but the texture will be rough and the sheen non-existant.
The problem with a beaded finish is it doesn't last all that long. Open pores, maxed surface area. Dirt, oils, grit and oxidation set in pretty quick. And it eats polish. A soft wire wheel applied with even pressure to a freshly beaded surface will knock the peaks off the surface, close a lot of the pores, and give it a soft metallic sheen.
The jugs, head and inner cam cover in this shot were bead blasted and wire wheeled:
The dyno, countershaft and cam cover ends weren't. They were cleaned with brake cleaner, sanded and then polished. If you ever plan to polish your dyno, clutch, countershaft and timing covers, re-read the first post - following it will save you a step or two.
NOTE: DO NOT sandblast aluminum. EVER. Fine grit in the sand gets in the pores of the aluminum, giving it a mottled, "dirty" looking finish that you'll play hell to get rid of.