cleaning valves

[Guest 1930]

Some of my old periodicals mention cleaning off the carbon that forms on the valves without removing the cylinder head but do not mention the actual process, I believe that it has to do with maybe putting an ignitable liquid down thru sparg plug hole and igniting. I think it might be referred to as burning off the valves but not sure, can anyone explain this to me and also wether it works or not, thanks

[nearchoclatetown]

In my opinion, they did a lot of unneccessary mantainance back then. I doubt that it is really needed if the car gets regular use and the carb isn't set up too rich. I've heard that dribbleing a glass of water down or UP the carb will clean the combustion chamber also. Maybe hook up a draft tube to the vacuum line to draw it UP? I've never tried it, then took the head off to see the results. With a blown head gasket it's usually easy to tell where it failed, as the area is perfectly clean of all carbon.

[Rusty_OToole]

This refers to cars of the WW1 era with very low compression.The combustion chambers were as big and open as the Carlsbad Caverns. They ran on straight run gas of low octane, next thing to kerosene.

After a time they would build up a soft black carbon inside. There were different ways to deal with this. One was to put a piece of brass chain down the spark plug hole and let the engine idle with the spark plug disconnected. This would knock the carbon out. Then you fish out the chain with a button hook and go on to the next cylinder.

This was a patented device sold in auto accessory stores.

The alternative was to take the engine down and scrape it out.

Once they went to high compression (in this context meaning above 5:1) and leaded gas came in (1928) they didn't get this kind of carbon anymore. They got a hard carbon buildup composed largely of additives.

Water or water vapor will steam clean the combustion chambers. Slowly dribbling water into the carb while the engine is running is one way to do this.

This was a common home remedy for spark knock at one time.

Be careful with this. Pour the water in too fast and you could get a hydraulic lock which could crack a piston like a walnut under a paratrooper's boot.

If you want to Mcgyver something try this. Get an old windshield washer tank and hang it under the hood. Feed it into the intake after the air filter. Run a switch up to the dash. With the engine completely warmed up, driving down the hiway at 60, throw the switch and let it run the tank dry. This will clean out your combustion chambers and valves if anything will.

[Guest 1930]

Thanks for the thorough explanation, I think that the mags I read about this in are very early or pre 28 for the most part.