I work in a shop. We use a presurized bottle that hooks to the air compressor lines and it sprays about 20oz of a cleaner chemical, similar to carb cleaner, but more mild. We run the sprayer right at the throttle body. I like to run about 60-90psi at 3000rpm's. I revv the engine, and yes if there is a lot of carbon and such it smokes a lot and stinks, but it makes a big difference. Afterwards, we usually do a tune up and you can see the metal surface of the piston. I also try to run it through the IAC, that makes a difference in idle quality.
Last year, with my car I took it for a spin and got the engine hot, then pulled the air tube with the MAF dissconnected and got the garden hose and turned it on low while holding the throttle open. Be real carefull, it's easy to hydrolock the motor this way.
What the cold water does is hits the hot carbon and basically goes from liquid to gas so fast it basically explodes blasting the carbon off the surface. One way to tell where you blow a head between the cylinder and the coolant becase it will be the really clean combustion chamber.
This won't clean the intake manifold very well, but a can of carb cleaner sprayed down the intake while the car is running will. It will also help clean the combustion chamber.
bluevenom867 said:
Leave the carbon on.Just get any loose stuff off the piston add leave the rest.Think of is as a free ugle piston coating.Haveing the carbon there increases compression and actually helps keep the piston cooler.Think about it, you got to get thru the carbon to get to the piston, so does detonation if it happens.Now of coarse if there is exsesive carbon you gotta take some of, but leave a little on.Trust me on this, I had a genius tell me this, and it makes perfect sense.Plus, do you know how hard that stuff is to come off?I was about ready to take the piston out and hit it with the DA sander befor the person told me this.
Genius?
Carbon is really bad, it retains heat, in fact gets real hot, causing detonation. It also causes an increase in NOX gasses which is bad if your trying to get past emmisions. Also, carbon will fill the valve reliefs.
Well, technically if you wanted to, you could leave the carbon on the pistons and run the car for a few million years and the carbon would turn to diamonds. Then you could trade you engine in for any engine you ever dreamed of.