Clean dirty pistons while still in engine?

-

WSUTARD

Well-Known Member
Joined
Jul 13, 2016
Messages
600
Reaction score
69
Location
Seattle, WA
Anyone have tips on cleaning my pistons while they are still in the block? Right now I am using carb cleaner as I figured it wouldn't hurt the engine since its combustible. It works ok but takes a ton of scrubbing with a rag.
 
I'd just keep any crud from down in the gap around the piston top. You don't want that in the piston ring groove.
 
Try a little Marvel Mystery Oil soaked into a microfiber sitting on the piston for a while. Followed by a non metal putty knife and grout brush(NYLON BRISTLE). Dont forget the shop vac.
 
WD40 works great on carbon, stuff rags on top of the pistons and soak them wit WD and let set a couple hours resoak and, it will take of the carbon with minimal scrubbing.
 
if it was running lean as someone thought,there would not be much carbon . I do not think it was lean. I would not go crazy cleaning, it is not a big deal. use wd40 or whatever, let it dry well then use a vacuum cleaner
 
Pictures are worth a thousand words for what you are dealing with but try to not invite trouble. Cleaners inherently dry out everything and if you are rotating the motor to get a better piston position for cleaning don't be bashful with wd40 or the likes as you go along...

I have found that in most cases to just leave it be unless you have a substantial amount of Carbon and even then you are limited as to what you can clean without removing Pistons...

Good luck,

JW
 
Here are one set of my pistons.
IMG_1373.JPG
 
if it was running lean as someone thought,there would not be much carbon . I do not think it was lean. I would not go crazy cleaning, it is not a big deal. use wd40 or whatever, let it dry well then use a vacuum cleaner
I sprayed a lot of WD-40 in my cylinders just to keep out moisture. ....a week later a rag removed most all my carbon...I was surprised!

Jeff
 
Put it all back together and run a cup of water through the carburetor with it about 2000 RPM.
 
I use scotchbrite pad and a small amount of solvent, just enough to keep the pad damp. I don't like using scrapers on a piston top.
 
Put it all back together and run a cup of water through the carburetor with it about 2000 RPM.
AGreed!
Or for those that live out in the country, ATF works great!
did you pull the head off just for carbon cleaning???
 
I had what I thought was a coolant leak. I'm not positive on that though since I didn't find signs of it.

I'm going to forget cleaning the pistons. Read enough to figure out it doesn't matter. I'm going to concentrate on cleaning the block surface. Going to use a scotch bright pad.
 
Put it all back together and run a cup of water through the carburetor with it about 2000 RPM.
I thought I was the only person who knew that trick. My High School Auto Shop Teacher, Mr. Farris, taught us that; only he used water in a Windex bottle. He said the water turned into steam and would clean everything as clean as a whistle. I have used it many times.
 
Same with the water my mate used to hook his wiper washer reservoir into the carb and whilst driving on the freeway inject the water in and plumes of crap left the engine.
 
I thought I was the only person who knew that trick. My High School Auto Shop Teacher, Mr. Farris, taught us that; only he used water in a Windex bottle. He said the water turned into steam and would clean everything as clean as a whistle. I have used it many times.

Our shop teacher, James P Lovett, (RIP) told us the same trick........but his method of delivery was a Coke bottle. I said cup because I figured hardly anybody would know what a coke bottle was. One handed delivery with your thumb over the top dribbling the water in. Works perfect.
 
I use a "mist-it" bottle to spray down the carb bores... Like from Windex. Bring the rpms up a little, spray as fast as you can down the carb until it studders and watch what comes out the tailpipe. ATF works too but harder to spray and smokes a LOT.
 
I use a "mist-it" bottle to spray down the carb bores... Like from Windex. Bring the rpms up a little, spray as fast as you can down the carb until it studders and watch what comes out the tailpipe. ATF works too but harder to spray and smokes a LOT.
Rislone dribbled down the carb does similar and makes a great bunch of smoke LOL
 
I have used a light duty cupped wire wheel on a drill to clean the pistons on two different motors within the last year.
Then I used compressed air and visual inspection to make sure there wasn't anything damaging left in the cylinders.

But yea, just leave it.
The deal with water is that when the water hits the carbon it soaks into it a little bit, and then when the cylinders fire that water gets instantly turned into steam and literally explodes the carbon off from expansion.
That's why when you see cylinders where a head gasket leaked coolant into it they are a lot cleaner than the others.

piston.jpg
 
Our shop teacher, James P Lovett, (RIP) told us the same trick........but his method of delivery was a Coke bottle. I said cup because I figured hardly anybody would know what a coke bottle was. One handed delivery with your thumb over the top dribbling the water in. Works perfect.


Showing you age again!!

I happen to know what a coke bottle is and it damn sure ain't no plastic junk. Good old glass, ice cold, from a vending machine. Damn I miss that.

And Pop Shoppe soda. But unless you grew up in PDX you wouldn't know what that was. And Ramblin' Rod. Damn I'm old.
 
-
Back
Top