How to De-Carbon Head & Combustion Chambers?

[Guest Silverghost]

Does anyone know of a good method to de-carbon an engine without removing the cylinder head?

I wish to remove carbon deposits from piston tops and combustion chambers of an older engine.

In the past I have heard stories of spray misting water into the carb at a fast idle or pouring small amounts of water down the carb...

I think this could be risky if too much water is used as it might hydraulically lock the engine as water does not compress.

Will water mist really remove engine carbon depsits?

Does anyone have any good methods to remove carbon deposits...short of pulling the cyliner head?

Are there any good products out there to de-carbon an engine?

How about marine two-cycle de-carboning can sprys?

Can you pour any product in to soak the carbon...

OR...

Should I just pull the cylinder head and use an electric drill with a brass wire brush and scrapers or the new 3M disc-pads?

All opinions & help appreciated!

[rocketraider]

What actually happens with the water is that, under combustion chamber temps and pressures it will flash to steam and "crack" the carbon deposits off. It's very effective though I have done it only once, many years ago.

"Sea-Foam" is also an effective CC cleaner. It can either be poured thru the carb or introduced into the engine thru a manifold vacuum port, or even the PCV valve (which has the added benefit of cleaning that system!). Sea-Foam is a very powerful petroleum solvent. Be warned though- used as directed by finally stalling the engine with it, and then letting it sit for a while to dissolve deposits, will make the most ungodly smoke cloud you have ever seen when the engine is restarted.

I try to run a can of Sea-Foam thru each of the cars every few months, even if all I do is dump in a can to about a quarter tank of gas and run it about empty.... Parts store knows I want a case of it when I ask for it <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />.

There are other brands of combustion chamber cleaner too. GM dealers used to have "Top Engine Cleaner" and "Engine De-carbon Solvent" on the shelf; pretty sure the other carmakers had similar products.

[Ron Green]

GM still lists a product for this as you noted. Don't have the number handy.

[Clipper47]

I have used "Sea Foam" with success. The product 'Techron" is supposed to be good also but Seafoam is my favorite . I usually use it on a back road not near any houses or at night so that the fire department isn't called out because of the white smoke! <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" />

[Guest Silverghost]

Tried the water treatment by misting entire window cleaner spray bottle of water into carb at a fast idle...

It did nothing!

Carbon still there...

No carbon came out the tailpipe...

Now trying the Chevron Tehron treatment...

Placed two bottles in 25 gallon tank with approx 20 gallons of gasoline in it.

Each bottle is for 12 gallons according to Techron directions.

Could not find SeaFoam im my area yesterday...

I will try again.

I will report Techron results...

Thank's for your help so far!

[caf]

I have had very good luck with a top engine cleaner that was sold by ford. I remember back in the 70's a car came into the dealership with a loud engine knock. I thought it was going to be a very expensive repair but the service mgr took it out back an poured in the engine cleaner then went to lunch. When he came back he started it up an it was silent, I couldn't believe it! Later I had the same experiance several times when an engine hadn't been run for awhile. I guess the carbon dries out and falls off onto another piece and the engine knocks like hell. both times I was able to fix it easily with the top engine cleaner.

[Guest Silverghost]

The two bottles of Techron in the gas tank appears to be a "Bust" as I see the same amount of carbon in the combustion chambers and the engine still "PINGS" like mad !

This engine is really full of top end carbon...so much it really pings under sight load.

Thermostat has been replaced with a cool 180" stat... Timing is fine...

glowing carbon seems to be causing pinging!

EGR valve replaced with a new valve...

Still engine pings like mad!

[Johan Boltendal]

You might try pouring little amounts of brake fluid throug the carb at fast idling,it smokes like hell,but it worked wonders back in the fifties decarbonising,learned the trick from my mechanic grand dad and dad as well.

Haven't tried it for a while,so have no exp. with modern brake fluids. Johan

[Dpass]

to get those stubbord carbon deposit out i had rerouted the window washer tubing

into the intake manifold as said before, and had brought the car onto the highway

after the engine was good and warm, i would coast down to 40mph and then step on

the accelerator to create a dyno like senario. as the motors struggles up through

it's rpm range and gains momentum, i would press the window washer button until i could

hear, see & feel a reaction then i would release the washer button and let the engine

regain it's rpm's. i would then let the engine clear out it's smoke and do it again

a couple more times, it's just seems to me that the difference is when the engine

is struggling under a dynamic load compared to sitting there is the reason the stubborn

carbon gets broken up and spit out the tail pipe. and im not even sure how someone

said in the prio post that they did not see any carbon chunks come out the tailpipe??

how does that happen, unless they have remove the header pipe and put a steel mesh over the

pipe? when i get back from my 1/2 hour highway drive you can feel & hear the difference.

P.S. make sure you do this on an empty highway, you can hurt someone from your cloud of smoke it's no joke!

[Ron Green]

GM sells a top end cleaner just for this. I have the GM # around here somewhere but can?t put my hands on it right now. The counter guy should be able to look it up.

[Guest De Soto Frank]

I believe "Sea-Foam" is a product of Kano Labs, the fine folks who make "Kroil" penetrating oil. You MIGHT find Sea-Foam at a boating supply house... but I've had to buy Kano Products mail-order or on-line.

Do a Google on Kano Labs and you will find the company's site and can order direct from them.

Have read quite a few reports from folks using Sea Foam, and they swear by its effectiveness.

Good luck !

<img src="http://forums.aaca.org/images/graemlins/cool.gif" alt="" />

[Guest Ken G]

I cannot resist re-posting the instructions from the instruction manual of my old Rover.

Ken G, 1925 Rover 16/50 (San Francisco)

DECARBONIZING ENGINE

BY OXYGEN PROCESS.

The engine can be decarbonized without removing head by making use of the oxygen process. A cylinder of compressed oxygen is necessary, also a strong flexible tube with a metallic nozzle of suitable length and shape to allow it to be inserted through the sparking plug holes, and to be turned round inside the head so that the stream of oxygen can be directed on to every part of the combustion chamber and piston top. A piece of 1/4 in. external diameter copper pipe, curved about 3 inches from its end, is suitable.

First turn off the tap on Autovac (the fuel pump) controlling supply of petrol to carburetter, and run engine until carburetter is quite dry. Remove bonnet completely by lifting away from radiator and from clip on clash. Protect wings and dash with suitable coverings, as the carbon leaves the cylinders in the form of burning granules.

Next rotate the engine until the exhaust valve of. No. 4 cylinder (farthest from radiator) is just closing. (The position of exhaust valve can be seen through sparking plug hole.) The piston of No. 1 cylinder will now be approaching top dead centre, and, when exactly at top of stroke, No. 1 cylinder will be ready for decarbonizing.

Now turn on oxygen until a fairly powerful stream emerges from nozzle of pipe, and direct this stream at sparking plug hole for 30 secs. Then touch edge of sparking plug hole with a lighted taper, and the carbon will immediately catch fire. Gradually work the nozzle all round the interior of the combustion chamber. and on to piston head taking great care not to allow it to remain in any one position for more than a moment, until no more carbon emerges. During this process, the operator should stand well out of the path of the burning carbon.

When no more carbon emerges, the oxygen should be turned off, and a stream of compressed air should be directed into the combustion chamber just cleaned to remove any fragments. (A few strokes from a powerful tyre pump will accomplish this if no compressed air is available).

To prepare No. 2 cylinder for decarbonizing, turn engine until exhaust valve of No. 3 cylinder is just closing, and set piston of No. 2 cylinder on top dead centre, proceeding as before. To prepare No. 3 cylinder, set piston on t.d.c. with exhaust valve of No. 2 cylinder just closing. To prepare No. 4 cylinder ?. etc. ?

The entire operation can be carried out inside of 30 minutes and a 10 cu. ft. cylinder of oxygen should be sufficient for one engine.