Poll - Decarbonizing engine with water
 

Okay, I've been doing some reading on previous threads about decarbonizing the engine by misting water into the intake, or in my case into the carbs.

I'd like to hear from those who have done it, and whether it was a good or bad experience?

What about misting in something like carb cleaner, or Ventil Sauber as opposed to running it through the fuel tank?

Seems like a simple "trick".

Some words from the pros would be great too!!

Jim

Did it yesterday on old Mercedes 200...it is friends car, mint condition but spark plugs has tons of carbon on them (car was driven by elderly gentleman before he got it). New ignition parts and water trick and now it runs like a champ.

Rev it to 3000 RPM and squirt a sizeable amount of water after the throttle.

If engine has lot's of accumulated carbon in cylinders, it works!

I did it once on an old 22RE Toyota engine and it reduced the compression numbers from about 195psi/cylinder to around 175-180psi per cylinder. The engine - due to high mileage I'm assuming - had built up so much carbon that the compression ratio had been raised and was knocking on anything less than 93 octane. After the "de-carbonization" I was able to use 89 octane...

Mike

I tried it last year for the heck of it while I was changing out my exhaust. I misted water into the intake and must say that I di not see much of anything come out the open exhaust.

I did not see any difference......probably because the engine is relativley low milage 68K.

I do hear that it does work on high milage engines.

Good Luck.

Mike

I tried it but I don't think I injected enough water. evidently it takes a fair amount. No result here. Engine came apart a month or 2 later and it was caked in carbon.

"misting" doesn't work. You have to squirt a lot of water to do any difference.

Yep, I literally poured water into the throttle body while keeping another hand on the throttle linkage to keep the thing running...

Mike

I put a garden hose into my intake...full blast...Just kidding ;) .

I can see a newbie happening upon this thread and pouring water into the intake with a bucket. How much is too much?

...and wouldn't the method of using a bottle of Techron or similar in the intake be more effective?

This is pretty standard for Gas Turbines. You flood the turbine with water at crank speed (10-20% depending on the model). You then let the engine drain out/spin cycle. Then you fire it up.

The carbon absorbs water. When it heats up, the carbon buildup explodes off the combustion hardware. Generally used for crude oil/heavy oil machines where the fuel contains waxes/long chain hydrocarbons.

How to properly apply this to a car engine, I am not sure. But on the GTs, the water is put in while the engine is cold, so the carbon is cold and will absorb the water.

If you put too much water in while running/cranking one of our engines, the piston will try to compress liquid water and most likely lead to pulled head studs.

If I were to do this, I would do it on a cold engine, with intake and exhaust ports open and flood individual cylinders in series, to make sure no liquid is left in the cylinder.

my $0.02

This trick works most of times but I believe most negative results stem from the fact that people are afraid of hydro-locking their engines and ae overly careful with amount of water. Which is probably a good thing as it won't hurt anything.

I don't say you have to flood it but motor spinning at 3000 RPM can swallow more water than you might believe.

A healthy sqirt from sport bottle is a good rule of thumb. It will start to stumble a little when quantity of water is just enough.

Great input folks.

Spoke with my mechanic this morning. He has been doing this for years. Water works, but he uses a different method. He uses chemicals, like carb cleaner, or ventil sauber and pours it in until the engine chokes down. Once to that point, he turns it over a couple times and lets it sit over night. He advised that when the engine is started the following morning, the shop gets blasted with carbon from the exhaust.

Probably a good idea when doing this to place a cardboard box or something similar in front of the tailpipe to catch the deposits.

Jim

I've done it on a 635CSi and a 944 with great results. I used a 16.9 oz bottle hooked to the vacuum line after the throttle body. At 3-4k the bottle drains quickly! Both times the engine ran noticeably smoother at idle and above. I'd follow up with a strong treatment of Techron, then change the oil when the fuel in the tank is low.

Hydrolock is a real caution that should be heeded......otherwise...go for it.

Wil

Another thing to think about is your catalytic converter. I would not do this on a car with a cat. All that carbon is going to end up clogging your expensive and hard to replace cat. I have been considering replacing my cat with a test pipe and saving the cat for the emissions tests every other year forever (since I have a 76 and not a 75). If I do this I look forward to trying the water cleaning technique.

Heard this many times and have done it on a lot of old cars. But on newer cars what does all the loose carbon do to the CAT? How about O2 sensors?

We did this in the late 50's to clear carbon out of engines. These were mostly V8's. We would pour water down the carburetor with the engine running at about 3K RPMs until it would stumble and the RPMs would drop way down. It produced huge billowing clouds of blackish gray smoke out of the tail pipe. I would be concerned about what it would do to the cats on modern engines. If you were pouring it down Webers one throat at a time, you should be able to dump quite a bit of water down them without worrying.

Anyone ever try this on a 3.6? I wonder where would you feed in the water?

Very intresting, how about just pouring some techron down the throat of the carb one at a time? Or does water work better some how?

Deutschmark wrote:
"....I'd follow up with a strong treatment of Techron, then change the oil when the fuel in the tank is low."

Good point. There's a good chance excess solvent will run into the crankcase and dilute the oil. It's a good idea to drain and refill the sump following this procedure w/Techron or equivalent.

Sherwood

I tried it using Seafoam hooked up to one of the vacuum lines. Smoked like hell but I could not really tell if it really got rid of anything since my car wasn't running badly in the first place.