Author Topic: Easy way to clean carbon off pistons/cylinder head combusion chamber? (Read 98988 times)

hevykevy420 · « **on:** February 23, 2007, 12:56:36 pm »

I've tried everything, B-12 chemtool, Seafoam, carb cleaner, nothing seems to work except a screwdriver and a very fine wire brush (don't worry, doesn't scratch pistons heads).

I'm ready to just give up and begin the reassembly. I've been scraping for hours.

pddpimp · « **Reply #1 on:** February 23, 2007, 12:59:46 pm »

If I remember correct, I've used brake cleaner. I put some in a pan and set the pistons face down in it and let them soak for a bit. Then the stuff wiped off.

bwaller · « **Reply #2 on:** February 23, 2007, 01:17:17 pm »

Permatex gasket remover.

Gordon · « **Reply #3 on:** February 23, 2007, 01:53:44 pm »

Regular old chem-dip works well, too.

BobbyR · « **Reply #4 on:** February 23, 2007, 02:28:53 pm »

You can try a torch and a wire brush. You have to be careful about how much heat you apply to the alumunum.

MRieck · « **Reply #5 on:** February 23, 2007, 04:25:33 pm »

GM makes a carbon remover that is unbelievable. I don't know if it is available to the public though. I'll get the part# and name from my machinist.

ChevelleSSLS6 · « **Reply #6 on:** February 23, 2007, 04:28:42 pm »

To prevent much carbon buildup... I mix about 3oz acetone to 10 gallons of fuel, have carbs adjusted right and good flow in and out of the engine, and it'll be good. Works with the B&S 8horse I have in a little tractor. Adding about a quart of toulene to the fuel mixture and it doesn't bog down in the thick grass anymore. I add the toulene and 1oz acetone to the 3gal tank before adding fuel so it mixes as I add the fuel. I should probably check cylinder head temps using straight fuel and "my" mixed fuel so I know I'm not burning stuff up!

I heard of a guy who used Jet Fuel in a cushman cart. He fried his engine, but it ran pretty darned fast!

Stevien1 · « **Reply #7 on:** February 24, 2007, 01:46:37 pm »

An old-timer once showed me how to clean carbon off of pistons with just an oven and ice water.....

Using an old oven (not the one you cook food in!), heat the parts up to 350-400 degrees then pull them out and spray ice water on the carbon. Wear safety glasses (along with thick gloves) as the carbon will "pop" right off the pistons.

If you don't have access to an old oven, try GM's Top End Cleaner or Mopar's Combustion Chamber Cleaner. Both are designed to work with the engine running and up to temp, but it's worth a shot on dissassembled parts........

hevykevy420 · « **Reply #8 on:** March 07, 2007, 01:49:16 pm »

I had some permatex gasket remover laying around and that stuff worked better than everything else I used. took 99% off. the rest will have to burn off!

here's to correct jetting!

BobbyR · « **Reply #9 on:** March 07, 2007, 01:59:36 pm »

Quote from: ChevelleSSLS6 on February 23, 2007, 04:28:42 pm

To prevent much carbon buildup... I mix about 3oz acetone to 10 gallons of fuel, have cabs adjusted right and good flow in and out of the engine, and it'll be good. Works with the B&S 8horse I have in a little tractor. Adding about a quart of toluene to the fuel mixture and it doesn't bog down in the thick grass anymore. I add the toluene and 1oz acetone to the 3gal tank before adding fuel so it mixes as I add the fuel. I should probably check cylinder head temps using straight fuel and "my" mixed fuel so I know I'm not burning stuff up!

I heard of a guy who used Jet Fuel in a cushman cart. He fried his engine, but it ran pretty darned fast!

What you have done with the Toluene is used one of the main ingredients of carb cleaner. The Jet Fuel frying a motor is a Urban Myth. Jet Fuel is a highly refined Kerosene which is much less explosive and burns cooler than Gasoline.

Hockers Choppers · « **Reply #10 on:** March 07, 2007, 02:02:21 pm »

Hey Kevy, I've got about the same settup as you, just got it back together. What are you running for carbs? I have the stock carbs with pods on my 78 F3, 120 mains, 2 washers under the needles, 1 3/4 turns out. Haven't rode it much but it ran good stock like this. Have a set of CR29's but haven't put them on yet.
Thanks, Jesse

Jonesy · « **Reply #11 on:** March 07, 2007, 02:02:43 pm »

Quote from: MRieck on February 23, 2007, 04:25:33 pm

GM makes a carbon remover that is unbelievable. I don't know if it is available to the public though. I'll get the part# and name from my machinist.

"GM Top Engine Cleaner". Ask for it at the parts counter.

Personaly, I prefer to run full out at 125 MPH on the interstate. Blows the carbon right out!

(Just kidding!)

ChevelleSSLS6 · « **Reply #12 on:** March 07, 2007, 03:25:14 pm »

Quote from: BobbyR on March 07, 2007, 01:59:36 pm

What you have done with the Toluene is used one of the main ingredients of carb cleaner. The Jet Fuel frying a motor is a Urban Myth. Jet Fuel is a highly refined Kerosene which is much less explosive and burns cooler than Gasoline.

Thanks for the correction!

BobbyR · « **Reply #13 on:** March 07, 2007, 05:58:21 pm »

Quote from: ChevelleSSLS6 on March 07, 2007, 03:25:14 pm

Quote from: BobbyR on March 07, 2007, 01:59:36 pm

What you have done with the Toluene is used one of the main ingredients of carb cleaner. The Jet Fuel frying a motor is a Urban Myth. Jet Fuel is a highly refined Kerosene which is much less explosive and burns cooler than Gasoline.

Thanks for the correction!

No you were on the right path with the chemical additive. Jet fuel sounds sexy but it is pretty low grade stuff. Now, you want to get some kick in your motor till it blows, add some Nitrobenzine.

hevykevy420 · « **Reply #14 on:** March 08, 2007, 08:12:44 am »

Quote from: Hockers Choppers on March 07, 2007, 02:02:21 pm

Hey Kevy, I've got about the same settup as you, just got it back together. What are you running for carbs? I have the stock carbs with pods on my 78 F3, 120 mains, 2 washers under the needles, 1 3/4 turns out. Haven't rode it much but it ran good stock like this. Have a set of CR29's but haven't put them on yet.
Thanks, Jesse

I have 120 mains right now with an airbox and I have not changed the needle position on the stock '78K carbs. IT WAS WAY TOO RICH THIS WAY, that is why I had all the carbon build up! I did buy some pod filters, but i'd prefer to use the airbox, so I am going to drop down to 115 mains, and see how it runs with the airbox. I like the smooth low end with the airbox, but may try the pods if it is still too rich with the 115 mains.

wohali · « **Reply #15 on:** January 11, 2011, 07:52:04 am »

As of mid-2009, GM Top End Cleaner has been reformulated

"Use with Fuel Injector Cleaning Fixtures such as Kent Moore J35800A or OTC7448 - Fluid is pressure fed into fuel rail with these devices."

Here's what used to be in the GM Top End Cleaner before the reformulation:

Quote

Petroleum Distillates 64742-52-5 NE NE NE 50 – 60
Light Aromatic Petroleum Naphtha 64742-95-6 NE NE NE < 5
Heavy Aromatic Petroleum Naphtha 64742-94-5 NE NE NE < 5
2-Butoxyethanol 111-76-2 20 ppm 50 ppm 5 ppm 5 - 10
Sorbitan monotallate 61791-48-8 NE NE NE < 5
Diacetone Alcohol 123-42-2 50 ppm 50 ppm NE < 5
Liquefied Petroleum Gas 68476-86-8 NE NE NE 15 - 25

To me this looks pretty close to Seafoam, so I'll try that next, and then gasket remover. So far my attempts with oven cleaner have been...OK, it's loosened the most crusty stuff, but the exhaust side of the head is still absolutely filthy.

Recommendation for scrubbing tool: "non-stick safe" Scotch Brite pads or "fake steel wool." Works wonders, zero scratches. Hey if it won't scratch Teflon off a non-stick pan, it certainly won't scratch your engine!

domer · « **Reply #16 on:** January 11, 2011, 09:12:34 am »

Quote from: BobbyR on March 07, 2007, 05:58:21 pm

Quote from: ChevelleSSLS6 on March 07, 2007, 03:25:14 pm
Quote from: BobbyR on March 07, 2007, 01:59:36 pm

What you have done with the Toluene is used one of the main ingredients of carb cleaner. The Jet Fuel frying a motor is a Urban Myth. Jet Fuel is a highly refined Kerosene which is much less explosive and burns cooler than Gasoline.

Thanks for the correction!
No you were on the right path with the chemical additive. Jet fuel sounds sexy but it is pretty low grade stuff. Now, you want to get some kick in your motor till it blows, add some Nitrobenzine.

about 15 years ago, my dad and i were puttin around a lake here in ca while a few buddys were racing some badass boats... us in our 1957 glassper with the matching johnson 35... ran out of fuel, said eh what the hell and filled her up with some high octane #$%*, 114 iirr. that little 2 stroke gained about 20 mph and lasted about 30 minutes. never did open it up to see the damage, but it was locked up!

fasturd · « **Reply #17 on:** January 12, 2011, 06:49:16 pm »

Soak in simple green I have seen it do wonders on carboned up Subaru pistons...

xedge4lifex · « **Reply #18 on:** January 13, 2011, 01:20:28 am »

depending on how tight of a nozzle you can get, make sure its really dry and try soda/bead blasting the CARBON stop when you hit metal. at the very least it would help create a tooth to use the stuff everyone else is talking about. also AIRCRAFT REMOVER in spray can form absolutely killed rust/gasket material when i have done head work. keep it wet, soak it, keep it in an area above 70 degrees, and close to an open fire.

Duanob · « **Reply #19 on:** January 13, 2011, 10:46:15 am »

I'd be inetrested in the de-carbonizing while running method. I'll try the seafoam first. My Bro-in-law has a tiny camera he uses for looking into cylinders to see any problems. I may borrow it before and after the seafoam to see if it really works. If not I'll try something else.

Kong · « **Reply #20 on:** January 13, 2011, 10:56:34 am »

Just go talk to any old baboon that has run big two stroke outboards for a lesson in de-carbing a running engine, often with Sea-Foam and just about as often with Yamaha decarb aerosol.

I used to have to do it at least once a year in my old Suzuki 200 (carbed) and 225hp (injected) engines. Here is how you do it. Bring the engine up to operating temperature and then have someone hold the throtle so as to maintain about 2000 RPM. As they do so spray the stuff into the carbs alternatively and sequentially so as to nearly stall the engine. As the can runs out spray it so heavy that it finally kills the engine. Then let the engine set for about 20 minutes. After that refire the engine and do not stand behind the exhaust, because you are not going to believe the crap that going to shoot out of it.

And that is how you decarb a running engine from a guy who has done it dozens of times.

PS, on edit: The reason for this was trolling. Those engines would be run to the fishing grounds (normally an hour or two run) and then brought down to idle, where they would run all day long just chugging along dragging baits. It builds up a lot of carbon that is not burnt off by the run back to port. Do that weekend after weekend and the stuff really builds up, you have to decarb the engines often. Of course today the big ones are mostly all 4 strokes and you rarely if ever see carbon build up in them like it does in the 2-strokes.

Duanob · « **Reply #21 on:** January 14, 2011, 08:30:33 am »

Hey Kong, that's what I use my Honda 7.5hp 4 stroke kicker for! It'll run all day at idle no problem. Thanks for the tip on de-carbonizing.

MCRider · « **Reply #22 on:** January 14, 2011, 08:38:04 am »

Sodablasting will take it right off. No chemicals, no toxic residue, totally benign, looks like new.

I've offered my services on "services". Ship pistons and valves to me easily. Combustion chambers are harder only because of shipping weight.

Buy a soda blaster and do it yourself.
before

after

takes minutes, tops, insides, ringlands completely clean.

water and/or compressed air cleanup

Goofaroo · « **Reply #23 on:** January 14, 2011, 08:48:53 am »

Once you get them clean, if you polish the tops to as smooth and shiny as you can get them it will retard future growth of carbon buildup. Also, you always want to run the lowest grade octane fuel that your bike will allow. Start by getting it properly timed and tuned and then start with the lowest grade fuel available. If it doesn't ping (and a stock engine probably won't) then you are good to go. If it pings, move up to the next grade. If you run higher octane fuel than is required by the engine, it will cause excess carbon buildup and expel more pollutants. The higher amounts of octane in premium fuel makes the fuel less volatile and it won't burn completely unless the compression in the engine is high enough to compress it more densely. Thus high compression engines require more octane added to the fuel to eliminate the knock caused by preignition of the more volatile lower octane fuel. Absolutely no power is to be had by running higher octane fuel than an engine requires. In fact, all that it will cause is an insignificant power loss followed by more carbon and more pollution.

wohali · « **Reply #24 on:** January 14, 2011, 11:26:47 pm »

I have a bead blaster. Looks like many on the forum have done chambers and exteriors (but not threaded/machined surfaces!) with glass/plastic beads, so I am not terribly worried...but will be taping a LOT of things up. And yes I have a giant dessicating unit on the compressor, so the air will be very, very dry and filtered.

Don't think I'll try anything but chemical on the pistons themselves, though; don't want to accidentally hit the side of the piston with the beads. Unfortunately my blaster can't use soda...

Fortunately the pistons don't look even half as bad as the ones MCRider posted.

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Author Topic: Easy way to clean carbon off pistons/cylinder head combusion chamber? (Read 98988 times)

Stevien1