Removing Carbon From Cylinder Head

I’d love to hear what techniques you all employ to routinely remove carbon buildup from cylinder heads. Soaking? Ultrasonic? Abrasives? Anything you’re willing to share would be appreciated.

I run KZ, so I’m doing this both for cleanliness as well as to ensure I don’t violate the cc rule. The head inserts come from the factory with a polished look, so I’m essentially looking to restore the head insert back to a “new from factory” status if possible.

This also begs the question, are there performance gains/losses that come from the combustion chamber being polished?

I have had good luck using caster oil and a small scotch brite pad, clean-up with a paper towel.


If it’s really bad, you can soda blast, then super fine grit sandpaper (1,000 up to 3,000 in steps) and polish compounds. That won’t remove any meaningful amount of material

After soda blasting

After polishing

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What are you using in the ultrasonic?

This version of simple green is non etching aluminum safe, i use it for heads and carbs. Around a 1:4 ratio with hot water. That head was 25 minutes in the tank.

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I use 50/50 mean green and distilled water, crank the heat and run it in 10min sessions. Air gun dry it, wd it, then hit it with brake clean. Zero issues on aluminum this way as well.


Makes sense, very little amount of time in the simple green, very very low chance of etching. I’m probably being a bit overly cautious using the aluminum safe stuff if its rinsed well after.

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Not if you’re like me and forget the alum parts are in there and come back a few days later…


Haha true, or my concern, not so much with heads, but with carbs, would be it doesnt get rinsed properly, and some simple green got left behind in a tiny passage or orifice and just ate away at it.

I’ve heard of guys soaking aluminum car rims in simple green and losing their luster.

Breakthrough suppressor cleaner.

I put the head on a tool for the lathe an spin it with polishing compound clean with some cleaner looks like a mirror

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Easy Off oven cleaner. It will blacken the aluminum.