• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

cleaning pistons

Swiggles

Swiggles

Donating User
Ive got some carbon built up on the top of pistons, how do i clean them off? i dont have air tools. please be detailed.
 


Soft wire brush (brass) and some carb cleaner or gasket removing spray. Be careful though. If your short block is still assembled, have a shop vac going next to the area to suck up all the carbon/crap, so it doesn't full in between the cylinder wall and piston.
 
the motor is out of the car and the heads are off...

but maybe ill just put it back together and try that method.
 
Thats what I'm saying...he did it out of the car as well...just poured it on all the pistons when the head was off...
 


ooh ok, i didnt read the whole thing, my bad.

what do i do if some stuff gets in between the cylinder walls
 
FWIW GM Dealerships carry the same thing, referred to as Top Engine Cleaner #12346535 & Upper Engine & Fuel Injector Cleaner #88861802

Stuff works wonders, Ive used it on several cars in the past. You just have to follow the directions to the letter or you can mess stuff up :th_winking:
 
i know you engine is apart, but water down the throttle body at an increased idle works really well. and i know it sounds like a bad idea (dumping water down the T/B) but if you have every blown a head gasket you'll notice that one piston looks really clean compared to the others, well what happens is the coolant/water mix steam cleans the engine basically, so the water down the t/b does the same effect and causes no harm to the engine. just make sure the idle is increased to 2000 rpms or so and just pour a steady stream down the intake.
 
HAHAHA im definitly not doing that! i understand the steam theory but theres no way im pouring water down my TB!

Im going to get some top engine cleaner.
 
deadcell608 said:
i know you engine is apart, but water down the throttle body at an increased idle works really well. and i know it sounds like a bad idea (dumping water down the T/B) but if you have every blown a head gasket you'll notice that one piston looks really clean compared to the others, well what happens is the coolant/water mix steam cleans the engine basically, so the water down the t/b does the same effect and causes no harm to the engine. just make sure the idle is increased to 2000 rpms or so and just pour a steady stream down the intake.
Click to expand...

This reminds me of the sand in the heads to "port and polish" them. Nice theory, but very poor effectiveness.

For what your saying to work would have to be a very finite amount of water, not a "steady stream @ 2000 rmps". A blown headgasket is already allowing excess pressure to escape so no further damage would occur and the leak is small that's why you don't hydrolock your engine when it gets a blown head gasket. If you poured water thru the TB it would mess up the Supercharger 1st, then would go into the engine and IF... IF it didn't hydrolock instantly (because water is not compressable) or bend/snap a connecting rod... it would instantly blow both headgaskets, 1 for certain and that would be TONS worse than just dealing with the carbon buildup.

Be safe, do like the little guy on your shoulder said... use the Top Engine Cleaner :th_winking:
 


deadcell608 said:
i know you engine is apart, but water down the throttle body at an increased idle works really well. and i know it sounds like a bad idea (dumping water down the T/B) but if you have every blown a head gasket you'll notice that one piston looks really clean compared to the others, well what happens is the coolant/water mix steam cleans the engine basically, so the water down the t/b does the same effect and causes no harm to the engine. just make sure the idle is increased to 2000 rpms or so and just pour a steady stream down the intake.
Click to expand...

I've heard of guys using a spray bottle to mist a wee bit of water in. Come to think of it, my when my buddy's girlfriend hydrolocked her engine it was clean as a whistle.
 
top engine cleaner isnt compressible either, and if you add too much top engine cleaner you can destroy a cat, water is harmless to a cat. i work at a buick gmc pontiac dealer and i have used this method more times than i can count and never had any negative side effects, but i also completely understand anyone being hesitant of trying this. If you did try this and did have an actual carbon buildup driveability concern such as pre-ignition, you would see a huge difference. also how would water mess up the supercharger?
 
deadcell608 said:
top engine cleaner isnt compressible either, and if you add too much top engine cleaner you can destroy a cat, water is harmless to a cat. i work at a buick gmc pontiac dealer and i have used this method more times than i can count and never had any negative side effects, but i also completely understand anyone being hesitant of trying this. If you did try this and did have an actual carbon buildup driveability concern such as pre-ignition, you would see a huge difference. also how would water mess up the supercharger?
Click to expand...


A) Top Engine Cleaner is like fuel with cleaning chemicals, it will ignite when the fuel does and will get burned out as well.

B)If it is dangerous to a cat, so its gas, and water alike. It will burn up and go out thru the exhaust. Yes it will smoke and make your car look like a freight train, but it has never clogged up a converter to my knowledge. If your having converter problems, you were having them before you tried using the cleaner, usually a carbon buildup in the engine resulting in a subsequent buildup on the cat too.

c) you do not work at a Buick GMC Pontiac Dealership. You work at a Buick GMC Dealership... Pontiac is dead, your job doesn't sell them anymore, lets not kid ourselves.

D) What works for you (a supposed ASE Tech) may not work for John Doe the "shade tree mechanic". Lets not have someone TRY something that you can do, and cause more problems that are now the fault of yours and this forums. Should the OP add too much water (regardless of how well it works for you) and it locks his engine, will you fix it because you told him to do it??? I highly doubt it.

We try to stick to tried and true info that anyone can use, not miracle fixes that someone can mess up and will result in even more problems than they were having originally
 
Misting water in your TB will not mess up your engine. Have you ever seafoamed an engine? Its essentially the same thing, the water is vaporized when the cylinder ignites. Youre talking like someone told him to stick his garden hose in the TB.Also as far as compression is concerned cylinder ignition doesnt occur until around TDC, so according to you any top engine cleaner would have to be able to be compressable as well.
 
Brian,

I used a couple shots of brake clean (you know me) and a plastic bristle brush. Didn't take any time and I could read the part number off each one.
 


TLSheff, i understand and respect your points and agree with you that a john doe should not attempt this, i was just trying to be helpful. this is a 0$ fix for carbon build up but i can understand why you or someone else would like to steer away from this, and as far as top engine cleaner goes if too much is added to the fuel, or too much fuel/cleaner mixture is sprayed into the engine then the car will run rich and begin to misfire, and what happens when there is unburned fuel in the exhaust? it destroys cats. so yes follow the directions take the risk and use that yourself just good luck not destroying a cat (or a fuel pump if injecting through the fuel rail) i'll try to keep my opinions to myself in the future.
 
I might be taking this thread off course a little, but my question is: why?

I think a thin layer of soot would be much less likely to preigition as opposed to a clean piston top with casting bumps.

If you have a ton of building such that it might affect your compression ratio or flake off and clog your valves etc, then sure, clean it. If not, I think it doesn't accomplish anything. It will be black again within 30 min of rebuilding.
 
Our pistons don't have casting bumps. They are smooth and coated.

IMG_4174.jpg


IMG_4164.jpg


IMG_4181.jpg
 
You must log in or register to reply here.
Back
Top