PatG

I have a question for any motor mechanics out there. Let me begin by relating my observation/experience. Back before I owned real cars I had a 4 cylinder Nissan that blew a head gasket. Coolant was entering one of the cylinders as a result. When I pulled the head I noticed that the cylinder where the coolant leaked was shiny clean. Every bit of carbon buildup was gone. Likewise the valves in that cylinder were completely clean and free of buildup.

Now for the question. Is there a safe procedure whereby one can inject water into the carb or intake and decarbonize the piston chamber? I can't be the only one who has made this observation. If one can do this is it worth it?

flood

I will be interested in the answer to this one.

I would assume that injecting water/antifreeze would be a huge :nono: but you never know.

inqbus383

Injecting water also cools the cylinders, preventing pre ignition. Edelbrock used to make water injection systems for these benefits.

Unfortunately injecting water also washes some of the oil layer away, resulting in more friction and ring wear. Some people even say that liquid gas from your accelerator pump can be detrimental after years of use.

PatG

I am not talking about injecting water all of the time, just as a maintenance procedure, say every 20,000 miles.

jbroughton

I have also heard that water, as you say, will clean carbon deposits in your engine. Also, GM sells a top engine cleaner to do the same thing. For more information on using it, see http://www.gnttype.org/techarea/main...e/cleaner.html

Hope that helps!
Jeff

63Banshee

This procedure can be used without negative impact if done with common sense. Three fine mists into the carb (about six inches away) under moderate rpm is all you need.

73Ken73

Water in the cylinders will break down the carbon deposits. It works best if the engine is real hot. Blocking the radiator with cardboard to raise the engine temp is a good idea. Only trickle small amounts of water into the carb and play with the throttle to keep the engine running. This trick was found out many years ago, 1920s or 30s , by Jaguar mechanics. The old Jaguars would build up carbon and then ping because the compression ratio would be too high. People who owned Jaguars would have to have the heads pulled off and the carbon cleaned every year ot two. Some smart mechanic figured out the water trick and made a fortune. I did it on an old Cadillac and it worked but the car back fired and blew up a muffler. I think that I added the water too fast.

63Banshee

Hence the fine mist idea. Water will not atomize like fuel does.

LT1man

I've used the GM top engine cleaner in the past. Recently looked at my valve train while doing some engine work-clean as a whistle on a 30 year old car.

MotorHead

Doesn't the water just wash the oil off the cylinder walls thereby increasing friction and decreasing engine life ?

Smokehouse69

Real oldtimers used to use a mixture of ATF and water, or sometimes plain ATF. Go out on some disserted road, take the air cleaner off, and with one hand keep the engine running by moving the carb linkage, while you trickle the mixture in slowly. My Dad did it about once a year on our old Chevys and Pontiacs. Always cured the pinging from carbon build up.
I would not recommend that anyone do this today, first of all the carbon can break off and really mess things up, secondly the amount of smoke that comes out of the exhaust would probably get you arrested as a gross polluter. The EPA would probably put you on their "10 most wanted list!"

UKPaul

Just my experience here: If you ever strip a motor & want to clean the carbon off of the heads then turn them upside down & fill each chamber with water. Leave it like this while you work on the rest of the engine & when you come to remove the carbon it will come off really easy (especially if you covered the chambers with degreaser 1st to remove the oily stuff). Never tried this on iron heads though.
I wouldn't recommend spraying water into the engine regularly as it will wash some of the oil out of the chambers. The wear caused by losing this oil is scary. A well known problem with old bikes is caused by leaky petrol taps that would regularly flood the carbs overnight. The engine would always start 1st kick on the coldest of mornings, but after a few months of this there would be incredible wear at the top of the cylinders due to the extra rich mixture washing the oil out (bore washed). I expect you'd have to regularly go mad with the water spraying to cause this sort of wear - but anything that could promote bore wear isn't good.
Also, don't overdo it with the amount of water that you put in. I've seen a bent rod caused by turning an engine over that had a small amount of water in it (plugs left out while it was raining).
Some vintage cars used to have primitive water injection that was basically a hollow copper tube wound around the manifold. This would condense water from the atmosphere & so drip very small quantities into the intake. The water, as well as helping remove carbon build ups, would sit on the top ring & help to seal it promoting better compression. Don't know how true this is but I got a 2 hour lecture on early tuning methods from a vintage car restorer last week when I asked what the copper tube was for (one of those times that you wished you hadn't asked!).
Are carbon deposits a problem these days??? When using our old 4* (highish octane, leaded gasoline) carbon built up quite rapidly. Now we're using modern unleaded fuel the carbon build up is insignificant. Unleaded burns hotter so maybe thats why there's less carbon (or it could be the additives that they say are in there?). When I've looked in engines that run on unleaded there is just a fine layer of light tan carbon in the chamber, the same types of engine used to have black carbon liberally spread around inside when run on our old leaded fuels.
:cheers:

emsrescu

I use the water down the carb keep her running. Just keep reving up as you add the water small glass will do you about 4 oz. My friend uses brake fluild but that smokes big time if your use it do it outside but not near the firestation. :smash:

Tom454

First, let me start by saying that I do head work... I machine heads... cut valves, cut valve seats, install bronze valve guides etc etc. I don't farm it out, I do this work professionally, in my own shop. Combustion chamber deposits is still an issue. But that will disappear when we go to hydrogen cars.

I re-ringed my 327 around 1984. At that time, I blasted the heads & valves, refaced the valves, and did a 3 angle valve job. I don't know how many miles I put on it with unleaded fuel since then, but it isn't very many. Definitely less than 6000 (I drive my other Vette). Just tore the 327 down to replace the cam. There are "medium" deposits in the combustion chambers, and on the back sides of the valves. The engine was not burning any oil, compression was good. If I were to guess, I would say the water trick would clean this much up. There are deposits, but not enough to drop off in chunks which would do damage. So... even with unleaded fuel, deposits can/will occur.

The cam had lost a few lobes and was in the process of melt-down. This is probably my own fault from letting the engine idle for extended periods of time just to warm it up.. High lift cam & extended idling = extensive wear. My bad. I should have known better. When I tried to start the engine, not knowing that the cam was toast, I flooded it many times. And I mean FLOODED it. When I tore it down, the cylinder cross hatch (which I personally honed into the walls) was completely gone, and when I turned the engine over by hand... it "squealed" just like an engine does when it overheats and seizes. This is the result of lack of oil on the walls & rings. I re-oiled the walls, but the rings/walls still squealed. Anyone who has ever built an engine properly knows that it should not "squeal" when turned over. The damage was done. Y'all be the judge.

The flip side is... running an engine without cylinder wall/piston ring lubrication causes instant damage to both the cylinder walls and the rings. Some ring sets I have installed recommend very light oil during assembly. However, all it takes is a couple revolutions of the crank to deposit enough oil up onto the walls to take care of business.

So will it (water) work? I think it will remove a "light dusting".
Will it cause immediate engine failure and the sky to fall? Nah.
Is it safe? I'm skeptical.
If you loosen up big chunks, you are in trouble. If you run an engine without wall/ring lube, you are in trouble.
I guess this is another one of those "pay yer money, take yer chances" things since none of us have the ability to shrink down and set up house inside a combustion chamber.

Tom



[Modified by Tom454, 12:57 PM 1/17/2002]

63Banshee

Some of you guys brought up an interesting point concerning washing the cylinder walls down. In all reality a person does more harm by “goosing” or revving an engine before shutting it off... just cause it’s cool or something. You guys know who you are!

Revving the motor gives each cylinder a heavy shot of fuel, which tends to wash cylinder walls down if the oil pressure isn’t kept up afterward (i.e. shutting off the motor).

When you consider that water and oil don’t mix (ever try washing oil off the driveway with just water?) and no one is stupid enough to inject water into their motor and then instantly shut it off, it is exceedingly worse to rev a motor just before shutting it off then it is to “decarbon” the cylinders with the water method.

...

I just remembered something that happened to me many years ago that sort of falls along the same lines as this subject...

My S/S Dodge developed a leak in the #8 exhaust port as a result of porting, rust inside the water passage, and core shift. On the second day of racing at Thunder Valley Raceway in OKC I started the motor up and it looked like I installed a steam engine the night before.

Long story short... I pulled the head and found a pool of coolant resting on the piston. Not only did I not bent a connecting rod (Two points for MOPAR connecting rods) there was no damage to the cylinder walls from “wash down.”

I brazed the port, put the motor back together, tweaked the chassis, and it ran it’s best ¼ mile time (10.99 @ 124) a few months later.


[Modified by 63Banshee, 11:44 PM 1/22/2002]