Water injection is pretty effective at removing carbon deposites.

I have seen people who trickle a hose from the town water supply, down the intake while they give it full load at fairly high revs on a dyno. Wella, instant tune up.

Regards
pat

If your engine is apart and you have a few days to let
the carbon crusted pistons and other varnished up parts
soak, I've had good experience with this:

http://www.airosol.com/McKay%20MSDS/50240-41-42-44-46.htm

(no affiliation)

Repeated exposure is nasty on the hands and you wouldn't
even want to think about getting it in your eyes so beware.
Over a few days it will soften and dissolve hard carbon
deposits with a minumum of effort though.

It's normally available at most professional auto parts
vendors that deal to the trade in 1 qt., 1, 5, 55 gallon
drums.

It stains/ruins many painted surfaces, some plastics,
and dissolves many types of soft rubber seals so beware
what you drop in the bucket.  (you might not ever find
it again or if you do, it won't look the same as when it
went in the bucket)  It's generally pretty harmless to metals.

Chumley

standard carb dip, why didnt ithink of it. ive soaked many a holley in it, thanks.

Lacquer Thinner, Lacquer Thinner, Lacquer Thinner!!!!!!!!!!!!!!  WORKS INSTANTLY.
THE BEST ENGINE PRE ASSEMBLY CLEANER AVAILABLE, AND IT'S CHEAP IN BULK. 5GALLONS AT SHERWIN WILLIAMS FOR LESS THAN $20. OR YOU CAN BUY A GALLON AT HOME DEPOT FOR $8 OR A QUART FOR $3-4  BULK IS THE WAY TO GO.

Shaun TiedeULTRADYNE Arl,TX(stiede@ev1.net)

thanks shaun.

Well, of course nothing (but nothing) dissolves carbon.

However, the chemicals you've suggested (carb cleaner, thinners) will do a good job dissolving gum and resinous stuff that holds the deposit together.

But please be careful with this stuff. Methylene chloride does not need repeated exposure to the hands to cause problems. Even at 20%, a spot will give you a burning sensation in seconds and raise a blister (handy hint to men - wash your hands before visiting the little boys' room!). Even worse is what happens if you inhale it through a lighted cigarette. I forget what toxin is produced but if they found any in Iraq it would make Bush & Blair's day.

Thinners is also pretty unpleasant (lots of xylene) and of course it's extremely flammable.

So don't take risks with this stuff - water injection sounds like a safer bet.

Regards - John

I just 'gotta' go with Shaun on this one. That and a putty knife used with care.  Wire brushes (rotary) on cast iron and 'plastic' bead blasting on alloy works as does water blasting (with a suitable detergent added) but is monumentally messy and I just don't have the patience for clean up.  I would rather take a few minutes to scrape the carbon and then clean it off with laquer thinner than make some kind of big deal out of what is basically an unplesant part of engine building in the first place.  Besides, the thinner takes care of the varnish on the undersides of the pistons and bottoms of the ring lands---stubborn stuff gets the bead blaster!  Carb cleaner is great, for carbs!!! I don't need all that gunk in my carb cleaner bucket.

Rod

John Harris is correct
These are moderately to quite nasty chemicals, and exposure should be minimised, especially the methylene chloride.

Thinners could be a number of solvents, often being aromatic hydrocarbons or keytones, both of which are flamable and moderately toxic.

I hav'nt worked in a chemicals lab for 25 years now, so I can't find my toxicology books, but if you read the labels, and do a web search, I am sure you will find heaps of info.

Of course smokeing, even without other chemicals present is dangerous. I wonder why Saddam Hussein didn't turn the arguement around and declare all cigarette factorys as plants for the manufacture of weapons of mass destruction, when you consider how many people are killed each year. It would make september 11 pale into insignificane

Regards
pat

Lacquer thinner is Nasty. Just like the radio add states about a certain cough syrup... It tastes nasty, and it works. While I hope none of us has to tast Lacquer thinner, It is an awsome engine parts cleaner, carbon /deposit removal, and it evaporates quickly and it works. No more arguing. LOL!  

Shaun TiedeULTRADYNE Arl,TX(stiede@ev1.net)

Shaun
I'm not arguing, thinners is a good solvent, and only moderately toxic. Just use with care and minimise skin contact and ventilate the area to minimise exposure to vapour.
Find out exactly what is in them and obtain and read the MSDS. After you read the MSDS, remember they tend to emphasise the dangers, so don't over react, but use caution.

Regards
pat

  How exactly does one go about injecting water? Just feed it in thru a vacuum connection while the engine is running? How much? Should it be hot or cold? How do you know if/when it's actually cleaned out the carbon?

I've heard of this frequently, but never tried it. I'm just curious...

You will Fry an O2 sensor when you run water through it in quantities large enough to be worth the time. Hot engine, cold or hot water. All you do is take the air cleaner off of the carb. Rev the motor to about 4000, then with a plastic cup full of water, dump it slowly but fast enough to start to bog the motor. Dump it at the same time that you slam the throttle wide open to get the motor to clean up. If you have the carb set right and you run good Gasoline, you do not have a build up. If the engine keeps trying to run when you cut off the key (Dieseling), it is full of carbon. This will be a case for the water or ENEMA as a friend of mine likes to call it.
Once again, GOOD gas won't carbon an engine if it is tuned right. Most carbbed engines with holley carbs have the power valve blown or are the wrong valve for the idle vacuume the motor has. This carbons motors up and makes them doggy also. A carboned up motor runs like it is full of timing when it may not be. The carbon glows and is a pre-ignition source.

 

Shaun TiedeULTRADYNE Arl,TX(stiede@ev1.net)

the motor im cleaning is actually a ford efi 1.9. light coating on the pistons and almost none in the chambers. didnt seem to be beyond normalfor 100k miles.

The water enema thing is more for cars so carboned up, that performance is significantly decreased.

I never did it to anything new enough to have an O2 sensor

I don't know for sure, but I can't see the water doing the O2 sensor any harm, as there is a lot of water in normal exhaust gass, but I can see the carbon really gunking up the O2 sensor

If you have normal carbon deposites on a healthy, It's not that hard to scrape, wire brush and polish

Regards
pat

ive had cars that blew head gaskets and had significant water (coolant) go through the exhaust, the o2 sensor functioned but when put on the scope the waveform was very "dirty" and "spikey" not smooth like it should have been. so yea a lot of water will ruin it.

When my car did a head gasket - corrosion ate from the water galley into the chamber in the head - I found one very very clean cylinder among several dirty ones. There wasn't _much_ coolant loss, so it can't take too much water to do an effective clean. Now I'm worried about my 02 sensor...

I mentioned adding water thru a vacuum fitting 'cause it seems most cars I work on are injected.

Didn't think about the O2 sensor. However, if you start a car that's been sitting for awhile, you would probably have a lot of water vapor in the exhaust at first. Then, if the sensor is pre-heated, it could be fairly hot when the water hit it. That doesn't seem to damage the sensor.

If it takes a lot more water to cause damage, I'd think you could damage the engine as well, maybe to the point of hydrolocking it? Hopefully you got rid of the carbon, so it will be a little easier when you rebuild it .

I heard of a product, I think it was "PK-44" that is actually supposed to work (at least on a motorcycle engine). Haven't tried it, though. Hmmm. I figured if I just put in half these miracle products in my crankcase, I wouldn't have any room for oil. Think that would work?

  . . . Steve

Lacquer thinner is a chlorinated solvent.  When chlorinated solvents burn in an engine (or a cigarette) they produce hydrochloric acid.  This acid will corrode metal, and especially the electrodes on an O2 sensor.  That is why all "Throttle Plate Cleaners" are non-chlorinated for EFI engines; The traditional and most effective carburetor cleaners have a significant dose of methylene chloride in them, so they are not O2 sensor compatible.

Incompatibility of water with O2 sensors is news to me, and for reasons others have cited seems a little cryptic.  There's antifreeze and corrosion inhibitors and especially silicates in most coolant leaks, so frying an O2 sensor from that doesn't indicate water is the likely culprit, IMO.

Engines will run with a surprising quantity of water in the F/A charge.  The problem with introducing through a vacuum hose is the stream will flow into the nearest cylinder only.  Commercial products that use this approach add an atomizer to introduce the water as an aerosol so the droplets will distribute more evenly throughout the manifold.  If enough water goes in that it pools in a cylinder then the motor will hydrolock, and the carbon in the cylinders becomes a moot problem.

Polyetheramine-based gasoline detergents in high doses can remove pre-formed combustion chamber deposits in some cases, while other detergent types can actually cause CCDs (there are lots of SAE papers on this).  If the engine is apart then a putty knife and soaking in whatever solvents you like should do the trick.

I've never tried this personally (i.e. don't blame me if it doesn't work). I've heard of people injecting uncooked rice down the intake while the engine is running. Of course these engines don't have catalytic converters.

Allen

throwing rice down a motor! sounds like a wedding or something. if i saw someone doing that, i beleive it would appear quite comical!

When I mentioned Lacquer Thinner, I intended it being used on disassembled engines. Not actually running through them to be burned. I apologize for not clarifying that initially.

Shaun TiedeULTRADYNE Arl,TX(stiede@ev1.net)

DrWebb writes:

Lacquer thinner is a chlorinated solvent.
___________________________________________

Are you sure about that?

http://www.astrochemicals.com/3036.pdf
http://www.flo-strip.com/images/dg-1.pdf
http://www.flo-strip.com/images/lt1.pdf
http://www.automagic.com/MSDS/24-msds.htm

There are hundreds of different blends of lacquer thinners,
I havent seen one currently mfd. that is chlorinated.(that
doesn't mean there isn't one or more)  The EPA doens't like
that idea in the same way they nixed R12(CCl2F2) freon in
favor of R134a. (tetrafluoroethane)  The parts dip I
referenced earlier is without a doubt a chlorinated solvent
though. Normally it has a less volatile oily type surface
layer that reduces the amount of vapor that enters the
atmosphere. (as long as it remains in the supplied
covered dip bucket)

Just a theory on the O2 sensor destruction when water
blasting with the engine running.  Hard carbon deposits on
the cylinder head and piston tops generally contain sulfur,
zinc, phosphorous and other trace elements found in fuel
and motor oils.  They burn if they are rapidly knocked off
the combustion chamber surfaces if the engine is running
with sufficient O2, additional fuel, and an ignition source
present.  It wouldn't surprise me that their oxides find
the O2 sensor(s) and the catalytic converter(s) on their
way out the tail pipe!  Water (as a gas) is a normal
byproduct of the combustion process.  If it was a major
problem at the normal concentrations, I would think we
would hear more about it.

GM and a few other mfgrs. also have some solvent based
injectable decarbonizing treatments(engine running) that
they recommend as a part of their TSB's.  

Chumley   

I'm going from memory here, but I have to agree with Chumley

All the solvents and thinners tins I remember reading, said Acetone, Methyl Ethyl Keytone, MIBK, Toluene, Xylene and/or Liquid Hydrocarbons.

Not a chlorine atom in sight, and for good reason. Chlorinated hydrocarbons are a much greater risk to health than are hydrocarbons or keytones.

Regards
pat

i always use diesel to clean the engine parts...i've  cleaned up heads and intake manifolds with it and it worked very well

At least for a running engine, I always use GM top end engine cleaner. Works like a charm, just make sure you do it far away from anyone who might complain, because the stuff that comes out, if it isn't toxic, sure smells like it.

For disassembled engines I always use either Gasoline or Lacquer thinner ( Lord knows it is not as safe as other things though )

Now wait just a second here.  I was given to believe that the primary concern when you burn chlorinated combounds was the production of phosgene gas.  I've never heard anything that said hydrochloric acid was a byproduct as well.  Although admittedly phosgene poses a much greater health risk than does HCL, I would still think that it would at least be worth mentioning it to someone.  Can anyone else either confirm or deny this claim?

I think you will find that O2 sensors are frequently based on a heated ceramic substrate technology which is very susceptible to thermal shock.  The sensor may have a shield around it to provide reasonable protection, but I believe a sudden deluge of water is likely to cause failure.

PJGD

I just looked up Phosgene on the BOC Gas site.

The BOC site has some alarming and specific warnings about Phosgene

It is HCl2O, so it certainly could be a by product of the combustion of hydrocarbons and chlorinated hydrocarbons.

It is extreamly toxic, but unstable in contact with moisture, where it breaks down to hydrochloric acid.

I GUESS that by the time it comes out the exhaust in contact with large amounts of water vapour, it is mainly but not completely converted to HCl.

Either way, not nice for people and parts.

Bottom lone. DO NOT PUT CHLORINATED HYDROCARBONS INTO A RUNNING MOTOR, and be very carefull about useing them to wash parts

Regards
pat

patdaly writes:

"At least for a running engine, I always use GM top end
engine cleaner. Works like a charm, just make sure you do
it far away from anyone who might complain, because the
stuff that comes out, if it isn't toxic, sure smells like
it."

Still laughing!  (I knew that!) Smells like it, and looks
like it!  Wynn's V.I.C., same thing!    But, . . . . it
works!  Post dusk treatment advised.

Chumley

Re patdaley writes
Opposite problem with Phosgene.
Colourless and odourless. First sign is some irritation of the mucouse membranes. By then you already have a fatal dose.
It kills you before you even know it's there

Regards
pat

Hi Pat.  I'll have to look that Phosgene gas info up.
Somehow, somewhere, I knew burning chlorinated compounds
locally isn't the thing to do.  I guess I haven't been
(seriously) exposed to it, at least as of yet.  I loved
chemistry in college until one of my favorite professors
one day told me, "You do know, Chumley, that as of today,
the average life of a lab chemist is 58 years?"

Thanks to techguru for asking the initial question for
this thread.

Chumley

I have recently stumbled across a product that has been a godsend.  Its schaffer's oil fuel additive #131.  Its a fuel additive that can also be used to clean combustion chambers.  I have a 1978 slant six that pinged like crazy and would only not ping while using premium 93 octane.  I ran it on regular but the timing had to be pulled back 7-10 degrees depending on the temperature.

I found bobistheoilguy forum and found out about the additive.  I bought a gallon.  It had instructions on the bottle on how to use it to clean the cylinders.  On fast idle, I slowly poured 16 ounces down the carb.  

The results were stunning.  I was able to go back up to factory timing settings, run the carb leaner, and it does not ping under any condition with 87 octane regular.  Also runs like it should and it gets 20mpg now instead of 14-16.

I like it due to the fact that it is made for an engine and does not create other problems that using atf, water, or  cleaners mentioned earlier in this thread do.  It can even be used in the oil to help clean the engine.

Dan

MOBIL1 synthetic used to clean a sludged engine works well in the oil pan if the engine gets 180*+.

Shaun TiedeULTRADYNE Arl,TX(stiede@ev1.net)

My coworker just tried some Berryman's engine cleaner. Now he's rebuilding it....

this ended up being a super good post, thanks for all the input guys.