Cleaning baked carbon off the head


My donor car had some small issues like some shattered piston rings and a few messed up cylinders... anyway, I'm cleaning up the head while I'm waiting on the block to be resleeved. I spent hours today with a steam cleaner and rag cleaning up the external surface of the head and then went to work on the internal aspect. I quickly found that steam didn't have the horsepower to clean the area around the valves where carbon had been baked onto the aluminum. I didn't even attempt cleaning out the exhaust ports :(

What is the best way to clean this baked-on carbon in the exhaust ports? is there a wonder chemical that I can use along with a brush? Or should I take this in to be cleaned at a shop?


Goblin Guru
Oven cleaner is made to clean carbon, but it will attack the aluminum pretty hard. If you are painting the engine, it probably will look fine, but is it necessary to clean the carbon off if you are painting it anyway? Sand it smooth, and paint it.


Goblin Guru
Pictures of how much carbon might help. Walnut shell blasting is sometimes done on the internal passages of a Direct Injection head.

Scott #321

Well-Known Member
You mention cleaning the baked carbon "in" the exhaust ports. If you are just referring to the black coloring I would not worry much as it will return again when you get the engine running. If you are referring to a thicker carbon build up repeated soaking in a carbon dissolving cleaner followed by pressure washing scraping light wire brush should get you there. Be careful of oven cleaners and very strong cleaners that may damage the aluminum if left to soak for too long. I have found a heat riser solvent or egr valve solvent work well on heavy carbon deposits and lean towards more elbow grease and less on the caustic/abrasive cleaners that can cause damage. That said I soda blasted the exterior of my motor after through cleaning instead of painting it.


Well-Known Member
One option could just be to get the head ported. I polished my combustion chambers myself and then sent it to Cat V Port Worx to get ported. If I recall correctly, you had mentioned running a Z57 turbo correct? If so, a ported head is probably a necessity anyway. If you do go this route, Josh at Cat V does phenomenal work - he will also clean the head, install new valves, seals etc. Not affiliated with Josh in any way, but as a very happy customer, I can’t say enough good things about him and his work.