Question about removal of valve & cc deposits

[Lyondellic]

I know that this may seem obvious to some, but I am wondering how some of the more effective fuel system treatments (Amsoil PI, Red Line SI-1, etc.) remove valve and combustion chamber deposits? Here are the possibilities that I can think of:

1) They cause the temperature in the combustion chambers to increase to the point that deposits burn up.

2) They slowly break up deposits and small amounts of the deposits burn up during normal combustion until all deposits are basically gone.

3) They break up deposits quickly and it takes a little while for the material to burn up, so some material either remains in the combustion chamber or catalytic converter until it burns up.

 

[Lyondellic]

Wow! 70+ views and no one seems to know how these cleaners remove existing deposits, or even what happens to the deposit material once it has been removed. What if big chunks of deposit material break free in a combustion chamber? My guess is that the combustion chamber would have to run hotter to burn off deposit material, much like an oven during the cleaning cycle.

I am really curious now.

 

[Gary Allan]

Heck if I can illustrate the mechanism for deposit removal. Most deposits on injectors/valve/combustion chambers are residual non-volatile fuel components that are left over when you shut the engine off.

 

[MolaKule]

The deposits are mainly hydrocarbons with a high carbon content. The solvents in the cleaner react with the molecules in the carbon to soften and then flake them, then the air turbulence lifts them to sweep them out of the chamber.

The particles are usually very small.

Combustion deposits from fuel are easier to clean off than deposits from oil.

Combustion temps with a fuel additive are not much higher than with regular fuel, and in some cases are cooler, depending on the FA mix.

 

[pickled]

Combustion chamber deposits are like coke breeze scraped from a blast furnace. I scraped some and ran Thermal Gravimetric Analysis (TGA) on them and they looked very similar to metalurgical coke breeze. I'm assuming these were from motor oil. Thanks for the insight MolaKule!!

 

[Lyondellic]

How do the fuel system treatments that do not contain a solvent remove combustion chamber deposits then? Is PolyEther Amine considered a solvent? I always thought that PEA is a detergent. Red Line SI-1 supposedly does not contain solvents, or so I have been told, yet is is considered to be top notch at removing these deposits.

 

[Gary Allan]

http://www.dcs.state.ok.us/SW_Contracts....achment%20Z.pdf

 

[Mephy]

Interesting document

 

[Jax_RX8]

Interesting paper, raises a few questions:

- Poly Ethyl Amine (PEA) is really considered a "dispersant" and not a solvent"?

- Does PEA affect oil films when in use as I have read that it is not recommended for use with 2 stroke engines - sounds like it has some solvency even if not officially considered one?

- Also interesting, that when PEA was in use (in the fuel), it caused considerable oil viscosity increases, within like 1000 miles or so. I don't think you would want to use PEA-based products (like SI-1 and some use Regane at low doses) on an ongoing basis then, but restrict them to occasional use only. Thoughts?

 

[Mephy]

Originally Posted By: Jax_RX8
Interesting paper, raises a few questions:

- Poly Ethyl Amine (PEA) is really considered a "dispersant" and not a solvent"?

- Does PEA affect oil films when in use as I have read that it is not recommended for use with 2 stroke engines - sounds like it has some solvency even if not officially considered one?

- Also interesting, that when PEA was in use (in the fuel), it caused considerable oil viscosity increases, within like 1000 miles or so. I don't think you would want to use PEA-based products (like SI-1 and some use Regane at low doses) on an ongoing basis then, but restrict them to occasional use only. Thoughts?

 

[MolaKule]

A dispersant is a chemical combination of a solvent and a surfactant:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=530318#Post530318

The surfactant reduces the surface tension of liquids and particles in order to keep them in suspension or to allow them to "flake-off," respectively.

Since PEA is a polymer, I suspect the the older PEA polymerized the motor oil and increased viscosity.

The newer PEA's used today have a slightly different molecular structure so as not polymerize the oil.

 

[Jax_RX8]

^^^ Thanks!

 

[axjohn]

So Molakule, would it be useful to have a regimen of different cleaners to add to the gas? I read on this board that all gasolines leave a slightly different deposit on the valves and combustion chamber, so the recommendation was to switch fuels every few months or so. So the different fuel's additive package would clean some of the deposit's the 'other' fuel left behind.

Of course, one would have to keep switching.

Would it be beneficial to rotate between, say, Techron Concentrate, SI-1, Regane, and some of the other high-PEA products, or with Neutra and FP+?

Wouldn't each get different carboneus deposits in different parts of the fuel/combustion system, thereby cleaning the entire system?

Thanks in advance, and I hope this isn't a thread-hijacker question.

 

[Gary Allan]

If PEA is the agent of choice in all the rotating cleaners ..just what would be the expected different outcome? I would reason that effectiveness would be altered by concentration and/or frequency of use.

 

[evoboy]

Often I have seen the results of a blown head gasket. The most visible effect is one piston crown , combustion chamber and spark plug are totally clean of carbon. The reason is coolant has leaked into that cylinder through the failed head gasket , turned to steam and scoured the surfaces clean , I mean clean like new !! This effect is rarely accompanied by any other deleterious effects. I've often wondered if water mist could be introduced into the induction system as a maintenance procedure to remove carbon build up. Maybe immediately prior to an oil change to prevent possible water contamination.

 

[demarpaint]

I have a friend that sprays water from an old Windex bottle into his throttle body while running his engine at about 2000 rpms. Its less likely to lock up an engine than pouring it in like many have done with carburetor engines. I don't think it would hurt anything, and done twice a year would probably help clean things up.

Frank D

 

[Gary Allan]

Sure. Water is used as a cc cleaner. I imagine it does a decent job on the hot back side of the intake valve too. It tends to stifle combustion unless metered properly with a healthy throttle.

 

[MolaKule]

Gary reminded me of one theory I read that said water droplets become supercooled and impinge on the hot carbon causing thermal "shock" which flakes the carbon off various components.

It has be used judiciously, however, I.e., metered carefully.

 

[Gary Allan]

I imagine that even dispersal is the hardest part. I don't think you can draw too much water in via vacuum. Assuming you don't form a siphon due to level differences ..I don't think you could draw too much with the alterations on the combustion process and the subsequent alterations to the vacuum's ability to lift a water column.

Now it's much harder to find a central manifold tap on all engines and throttle bodies may be biased to one end of the engine. Even centrally located they will suffer the same issues that TBI injection did ..which I imagine could be compensated for with just doing it more often ..or longer.

I've done this with other agents, but I think routing a vacuum line into the passenger compartment (via the cowl/hood gap and through the window) and introducing the stream at highway speeds would produce the desired effects. Again, the distribution point has to be centrally oriented for the vacuum tap.

I wonder how a 50:50 blend of water and IPA would work

 

[chevrofreak]

Some people use windshield washer fluid, since it has methanol in it. Someone claimed it was 50:50, but I doubt that.