How to clean engine internals
 

What do you guys use to clean the baked on carbon off of the rotors?

Mmo

I use my pneumatic 90* die grinder with scotch-brite 2" circular pads. Couple of minutes tops. No solvent mess, no fuss...

This setup also works well for any old gasket removals...

Do you mean with the engine in the car and assembled, or on a bench disassembled? It makes a huge difference, as the two previous answers show.

Rotors: 3" wire brush (flat disc, not cup) mounted on drill or die grinder...or soda blast. Then take old seals and dig out the grooves for side seals and apex seals. Take a dremel tool with a small cup brush and insert it into the corner seal slot to clean that. Dip in a solvent/parts washer tank to get the leftovers out of the grooves, and final cleaning.

Rotorhousings: soak in parts cleaner/tank. Remove...take above mentioned wire brush and clean side mating surfaces to shiny bare metal, not staying in one spot too long. A side angle grinder with a cup brush mounted will do the work much easier and faster. Pressurewash or soda blast the externals. Pressurewash the coolant passages to remove dirt and such.

Irons: soak in parts cleaner/tank. use a small jewelery screwdriver to scrape out the remnants of coolant seals (now softened by the solvent) back down to bare metal. Use the disc wire brush to go back over the grooves, press it into the groove as you use it, it'll clean it quite well. Pressurewash externals and coolant passages. Be sure to blow off with compressed air or light rust may set in.

I heard that Amsoil powerfoam works really good. For cleaning while the engine is still in the car.

I used a drill and a 3 inch brass brush. Worked like a champ.

Rat

PB Blaster also works nicely on the rotors, as well as oven cleaner. Just keep it off the bearings.

For most of my general cleaning, I use a parts washer filled with generic "gunk" degreaser. Not the best for carbon, but wonderful on everything else.

I worry about using anything too abrasive on the rotors, as it can strip the cadmium coating and thus make them much more prone to corrosion.

Thats why I used a brass wheel. You think thats too abraisive?

Brass brush I wouldn't worry about using, but a spinning brass wheel, I dunno. What does the coating look like after that?

I worry about anything involving a power tool. :) There are so many cleaners around dissolve carbon with very little effort, so I have never had to resort to mechanical means. I scrape all grooves with old side/apex seals. For the irons, I have ground down a flatehead screwdriver to perfectly fit in the coolant seal groove.

Hmm.. Oh well.

I used a brass brush on a drill.. Guess I took some coating off. Good times!

And Wayne, the rotors looked fine. I just used the brush to knock off the carbon. Once it was off, I moved to another spot.