Surprisingly, I haven't found much on here regarding carbon removal. I have quite a bit of carbon build up on my l98 pistons and heads. I've found via google a lot of suggestions on what works. Automatic transmission fluid, vinegar, permatex gasket remover, etc. I've got aluminum heads so I've got to watch what I use. Keep in mind, the heads are off of the engine, so seafoam recommendations won't work for me at this point. What say the thirdgen guys?

Steve

 

WD40, marvels mystery oil... sopft scrub pad. Clean all off and vacuum out especially around the rings. Then turn the engine over clean crap off walls, spray with some brake clean and bring piston to TDC and vacuum around rings again, repeat until there's no crap left on the down stroke. After immediately lightly lube walls and change oil. That's how I do it.

 

Doesn't too much matter what you do; in a few hundred miles it'll be back just like that again.

Not usually much point in getting very excited about it one way or the other.

 

Some carb cleaner will remove most of the deposits.

 

I'd just wait til you have it back together, seafoam it, and not worry about it for a little while. Just IMO

 

I had a Kohler engine on a garden tractor that I removed the head to replace the head gasket. I noticed some carbon deposits on the piston and valves. I always heard good things about Marvel Mystery oil, so I poured some on the combustion chamber and let it soak a couple days. When it was time to put the head back on I wiped everything down with clean shop towels. I was amazed as the carbon had completely softened up and wiped off easily!

 

I usually soak in mineral spirits for a couple of days, then hit it with carb-cleaner from a spray can.

Vinegar is really great on brass carburetor parts, but don't use it on aluminum or even steel for more than just a few minutes or you will lose material.

When I need stronger solvents I break out the Acetone or MEK.

If for some reasons chemicals fail, then I use a rotating wire-wheel, and/or scotchbrite pads.