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cleaning pistons!

80K views 19 replies 17 participants last post by  xzero117 
#1 ·
what is the best thing to use for cleaning the carbon of of pistion befor i reinstall them?
thanks
 
#5 ·
I just put some rings in my 91 prelude.It was an oil burner so the tops of the pistons had a lot of carbon on them(in the center of the piston).I soaked them in my parts washer and it didn,t seem to help much.
I had some BG intake cleaner that I had not used.I soaked them in it and the carbon came right off. :D
I don,t build engines that often.I would kinda of like to see what others use also.
 
#7 ·
When I cleaned my off I had my engine on a stand so this was a little easier to do. Rotated it so that the side I was cleaning faced down and slightly to the side. The bores on either side of the piston I was cleaning where tapped over so that no dirt got in them, also keeping the holes for the head bolts covered. Rotate the positions till the one you want to clean is at TDC and used a wire wheel to clean it.
The bore was lubricated with a thin coating of oil since the engine had been out for an extended period of time.
I took a wire wheel and went over the large portions of the piston till it was clean
The small dishes in the piston easily cleaned with a brush. Getting all the little bit out if there can be a pain but it completes the job.
When all the work was done the finished piston was rotated back down the bore the oil caught most of the dust.
I cleaned the oil away from there and the job was done. Also make sure to wipe down the piston top for left over dust.
A nice repeat process to go on from here and of course a double triple check at the end just remember how little it takes to kill a bearing.

... for an engine in a car i would use the same process but be even more careful about dust falling down into the ring land while cleaning. best of luck.

Chris
 
#14 ·
joe_padavano said:
Oven cleaner is the best, least expensive way to remove carbon deposits.
I would not suggest applying oven cleaner {acid} to a set of pistons.
A quality ring grove cleaner can take care of the carbon deposits there. A dishwashing pad made of brass guaze {Chore-Boy ect.} can clean most of the surface stuff on the skirts whithout gouging, and the carbon on top can be scraped with a dull pocket knife. The trick on the top of the piston is to keep a smooth surface, even if it means leaving a thin layer of carbon in some spots.
True: Excessive carbon film on the top of the piston can lead to preignition issues.
And, 'No carbon' is excellent.
But: Scatched surface imperfections on top of the piston will created an area for carbon to collect in that space and will enhance combustion chamber ignition local to that specific area of the piston, rather than allowing a uniform charge ignition across the piston top in that chamber.
JMO :)
Have Fun !!!
 
#16 ·
techinspector1 said:
If you are going to scrape or wire brush the pistons, run each one up to top dead center to do it, then use a shop vac with a snorkel attachment to vacuum the crud from around the ring lands. I've done it many times. No shop vac? Use mom's or girlfriend's or wife's vacuum cleaner.
Be sure to hide it in a barrel so she thinks it's a shop-vac. :D
 
#18 ·
My father used to build sports cars and taught me this neat trick how to get carbon, dirt, etc out of an engine cylinder (with the pistons in the engine).
Turn the crankshaft until the 1st piston is at the bottom of its stroke,
Then wipe the cylinder wall down with a heavy oil (straight 30 wt or heavier) then turn the crank until the piston up until its about an inch from the top of the cylinder and stop and turn the crank in the other direction.
As the piston travels back down the dirt etc, will remain suspended in the ring of oil running down the cylinder wall and you just wipe it out with a clean rag.
Then continue until all cylinders are clean.
This method traps the smallest particles.
Using a vacuum 1st would be a good idea.
 
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