Looking for advice on cleaning my piston heads and combustion chamber. I used chem dip to clean the head combustion chamber and it worked like gang busters in that isolated area

Now as far as my piston heads I've use wd40 but there's still some carbon left that bother me. My question is, is it okay to use the chem dip to clean the tops of the pistons knowing that it could run down the cylinder walls? Obviously I'm gonna change my oil after this is all said and done but I'm wondering if it's going to leave behind residue that could contaminate future lubrication.

Thanks in advance for any advice and help

 

Any engine that has a few thousand miles on it probably has some carbon built up on the top of the pistons. There's nothing inherently wrong with carbon build up unless it's like 1/8 inch thick or more. I wouldn't really worry too much about it. The real risk is the small pieces of debris which get between the piston and cylinder above the top ring. There's no way to clean that small crevice without pulling the pistons out. Especially if you use Scotch Brite pads or Roloc disks which make a very fine abrasive dust. Spray some brake parts cleaner or whatever, blow it out with compressed air, and let her eat.

As far as cleaning residues, brake parts cleaner should wash away anything you'd be worried about. WD40 or motor oil should be used on the cylinder walls to help with lubrication for initial startup. If you're not dropping the pan, definitely change the oil after the first heat cycle.

 

Thanks @arlindsay1992
I've got a picture attached of what I have after I cleaned with the Wd40. The thing I'm concerned about is some being clean and some not, could that create hotspots in the combustion chamber?

 

I don't see anything out of the ordinary there. I don't think I've ever seen carbon deposits that are perfectly evenly distributed over the top of the piston. Some parts are always going to be cleaner. As long as there are no big chunks and it's not at risk of easily flaking off I wouldn't worry.

With what you have there, make sure there's no loose particles and grit on the piston and between the piston and cylinder. Clean up the deck surface and head bolt holes. Don't use Roloc disks or similar on the deck surface. A new OEM gasket, oil free and flat head and deck surfaces, and light oil on new head bolts and you should be all set.

 

Me, I'd run an ordinary "Scotch-Brite" on the tops of the cylinder walls to take off that carbon.

 

Since I've got it taken apart I think I'm gonna do the extra work to get him shiny and hopefully wont ever see this part of my engine for another 200k+. And I'm debris free, been super particular about that @arlindsay1992

I've heard to not use regular scotch brite and only use non-scratch because it could mess with your cross-hatching. Is that not the case in your experience? @scope103 All that I've cleaned is been with non scratch and its been mildly effective to be kind.

 

I wouldnt use any abrasives on the walls, as you said because of the cross hatching. If it were my motor, Id leave that carbon until I was ready to dissassemble the block n do the full job. But everyone has their own methods and Im no expert.