Searching for tips on cleaning the combustion chamber/pistons Options

[detoxcowboy]

Anybody have any tips on cleaning out the combustion chamber by hand not bead blasting etc.. wife won't do it..

[MBowman325]

There was a consensus on the MCML several years ago about using distilled water down the carb. About half a bottle slowly, then pour the rest in, stalling the engine, at least if I remember right. Give it 10 minutes and then fire it up and run it. Long drive afterward was recommended to ensure that the oil was dry.

There was concern about hydrolock which those that did it never seemed to encounter. I'd think there might be issues with cracking things too, though that never came up at the time. Maybe it was recommended to do on the first start near immediately? Would have to pull my archives out.

Not sure I'd try it on the 914, even excluding the FI predicament.

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Soak it in a liquid and wirebrush it?

[DBCooper]

There was a consensus on the MCML several years ago about using distilled water down the carb. About half a bottle slowly, then pour the rest in, stalling the engine, at least if I remember right. Give it 10 minutes and then fire it up and run it. Long drive afterward was recommended to ensure that the oil was dry.

There was concern about hydrolock which those that did it never seemed to encounter. I'd think there might be issues with cracking things too, though that never came up at the time. Maybe it was recommended to do on the first start near immediately? Would have to pull my archives out.

Not sure I'd try it on the 914, even excluding the FI predicament.

Anyone have an old English sports car or motorcycle and see instructions on pulling the head for "decarbonizing" periodically? There were no additives in the gas back then, and rings weren't what they are today, so the chambers built up lots of carbon deposits. Some smart guy realized you could use water and steam for "decarbonizing" instead of pulling the heads. You see it sometimes when a car's been driven with a leaking head gasket, the piston in that cylinder is super clean compared to the others. And there were people in the Forties and Fifties who ran light water injection, and the engines were spotless when you pulled a head. We used it in the seventies, too, for cars that were well tuned but still dieseled or pinged from running lean with carbon deposits. It was quick, easy and cheap, so we'd try it first, and if it didn't work then we'd pull the heads to clean up.

You get the engine hot, then slowly pour a pop bottle or quart oil can of water in, just a good solid stream while you keep the revs up. Not enough water for any possibility of vapor lock, but you'll be making STEAM baby, and you'll smoke out the whole neighborhood! You've been warned. DON'T dump a bunch in at once, and no reason to turn the car off. That superheated steam is what cleans the chambers, so when the smoke (vapor) dies down you're done. Yes, drive it a bit afterwards, but if the engine never stopped then as soon as it stopped smoking (steaming) there's no water in it any more. No, it never hurt anything, but of course that was before catalytic converters. I know that water vapor won't hurt them, but I don't know about what the carbon going out the back would do.

Bottom line is that it works sometimes. And if it doesn't you've wasted some time and a little water, and will be doing the mechanical repairs you would have had to do anyway. Once the engine's apart I just use solvent, a scraper and then a small light wire wheel to clean up.