cleaning combustion chamber carbon with water

[jemeadows]

hankL mentioned this in my previous post. for anyone who knows how to do it... please tell me how i can give it a shot. for those of you who don't know my story...i have a bad case of spark knock. i have narrowed it down to my stock timing chain with 162K miles (yes, it will be replaced asap) and carbon buildup. my performance computer has come out for the time being for my engines sake. this is something easy i want to try before i go to soaking my chambers with chemicals. thanks
eric

[hemivaliant]

Using water is the only way I know how to other than removing the head and scraping it off.

In your message I'm not sure if your asking what the procedure is for removing carbon from the combustion chambers with water. If you are here's how I do it: 1.Get a spray bottle and fill it with about 2 cups of water, 2.start your engine and let it warm up to operating temp. 4.while reving the engine spray water down the TB or carb, make sure you spray the water in it as a mist. 5.continue until all the water is gone. For a heavy buildup of carbon it may take more than two cups of water.

HV

[This message has been edited by hemivaliant (edited October 06, 2000).]

[HankL]

Danger, Danger, Danger.

What follows is a description of a method to clean carbon out of a Ram's cylinders that is not totally developed or tested to be safe to your engine. Try at your own risk. It is safer to use fuel injection cleaner frequently instead.

What I did was take a 18 inch long piece of half inch internal diameter clear plastic hose from Home Depot and push it onto the air conditioner drain on the passenger side of the engine compartment. The AC drain is hidden below the AC dryer. You will need to ream the end of the hose inside edges slightly to get it to push on to the AC drain easily.

I then took the PCV valve loose from its grommet. The bottom of the PCV valve is also half inch. Press this into the half inch hose from the AC drain. You now have water injection system that turns on when you turn on the air conditioner.

Note however, that this water and air going through the PCV is not filtered. More on that later.

If the 3/8 hose from the PCV valve to the intake manifold is not long enough you may need to get some additional length of 3/8 hose. I think it is best to have enough 3/8 hose so that the water from the AC drain runs downhill all the way through the 1/2 hose to the PCV valve, then the 3/8 hose lifts it up to the intake manifold.

Tie this hose system away from the heat of the exhaust.

I felt it was also important to keep the PCV system working. Larry Widmer says that the PCV system is key to keeping oil from being contaminated with water - not just water from this AC injection - but all exhaust gas has water in it and the part of the exhaust that blows by the piston rings gets into the oil and needs to be vented away by the PCV system.

So I went to an auto parts store and bought a length of 3/16 hose and a Purolator 10007 PCV that had two outlet nipples: one the normal 3/8 that I plugged off, and another nipple that was 3/16. I ran the 3/16 hose from the 'test port vacuum nipple' on the other side of the Ram's manifold and then connected it to the Purolator PCV valve, and pushed new PCV valve bottom into the grommet for the original PCV valve on the passenger side valve cover.

How much water does the AC drain put out ? On a humid 90 F day I measured 0.3 gallon in an hour by dripping it into a bucket with the blower on the 2nd notch and the temp control turned to full cool. It could be more or less depending on your weather. Setting the fan to higher levels than 2 will condense out more water.

I found that this much water injection will not keep the Ram from pinging at full throttle when you first try it. It took two tank fulls of gasoline run while using this water injection to have the pinging go away. It looks like this modest amount of water slowly cleans away the carbon deposits.

The water injection does affect driveability. Sometimes when accelerating way from a stoplight the engine would miss and buck, then catch strongly.

There will be weird sucking/gurgling noises heard in the Ram's cab coming from the passenger side.

You need to turn the AC off four or five miles before the end of your trip - or the next time you start your Ram the plugs will be wet and it will start a little harder.

What I don't like about this method is that the water {and some air} being injected into the intake manifold is unfiltered. I definitely would not drive a Ram this way on a dusty gravel road.

I have been looking for a fuel filter I could put in the the 3/8 hose between the PCV valve and the manifold. I bought a Fram G2 fitler for $2.40 at Walmart that I thought would work, but its end connection nipples were 1/4 and too small. At an Autozone store I saw a "Chrysler Vacuum Hose filter" that looks like it has 3/8 connections and might work.

CAUTION: it is unlikely, but possible, that a big enough slug of water could flood a cylinder. This would cause the piston to rise against a cylinder filled with water - which would crack the cylinder head or piston !

It is also possible that if you don't turn the AC off well before you stop the engine that enough water will be in the cylinder to rust the cylinder walls.

And now the bad news: within 3000 miles the carbon deposits came back and the engine pinged again slightly. Running one tank of gasoline with the water injection system hooked back up stopped the pinging again.

One other note: when I took this system off, I kept using the Purolator 10007 valve with the two outlets. I now have a PCV valve that injects into both sides of the intake manifold through the 3/8 original port and the 3/16 vacuum test port. I feel that the factory PCV system injects the blowby gases with its load of oil vapor into one side - where they go mainly into driver's side cylinders - especially #3 and #5 cylinders. In addition, the fuel injection system and O2 sensor need to have all cylinders getting the same mixture for best mpg. Injecting the PCV into one side seems to me to make one bank of cylinders 'rich' from lack of oxygen.

My 1995 Ram has the PCV system on the passenger side. Sometime (1998 ?) Dodge changed this to a PCV system on the driver's side. Why ? I don't know, but I suspect it has to do with the pinging problem. Oil vapor injected into the cylinders from the PCV system is one source of carbon deposits in cylinders.



[This message has been edited by HankL (edited October 06, 2000).]

[MeanGreen98Machine]

About 20 years ago I read in some performance magazine about using a water bottle, a brass thumb-screw metering valve and some vacuum hose to inject a fine mist of H2O into the intake via a "port vacuum" tube. You'd only get a tiny mist of water under heavy acceleration. The harder the acceleration the more water. The purpose was to "cool down" the air/fuel charge enough to allow advancing the timing a couple more degrees without preignition/detonation for faster performance.

I suppose a water injection system like this would work to help remove/reduce carbon build up -- and maybe cure the pinging problem in some really tough cases.

Two things come to mind, however. Using good quality gasoline with plenty of good detergents (hi octane does not necessarily equal hi detergent) and occasionally adding a bottle of Chevron Techron, or the like, should make this whole issue moot. And, it seems like some of us are worrying excessively about a small bit of carbon build up. It's not like we're running diesel fuel through our engines.

For what it's worth.