Topic: Disolve Carbon Build Up on Pistons

[chewbacca5000]

I am going to be rebuilding 3 or 4 engines over the winter and would like to be able to pour something into the cylinders to dissolve the carbon build up on the pistons.  Not rust removal just the carbon.  I can test on a few spare pistons with carbon on them.  Any ideas?

Thanks!

[ekpent]

Not sure of a magic elixir but maybe set them upside down in a little pan of kerosene or diesel fuel to soften it up.Some of those powerful cleaners like Greased Lightning and such have also surprised me before how well the work. Probably will still have to apply a little gentle 'elbow grease' though.

[Rigid]

Gunk brand makes a caustic engine cleaner but that is to be used with the pistons off the engine and immersed for 24 hours.  Anything you put into an assembled engine will end up in the crankcase so seals and gears will be at risk for contact.  Most specialty auto parts stores will have gunk or equivalent.

[tortelvis]

I know it sounds crazy but a drag racer I knew back in the 70s told me his method. I had an old crappy Renault that would run on for 10 minutes after switching off. He told me to remove the air filter, start the motor and pour water into the carb! He swore that water would disolove the carbon buildup quicker than anything else. He said white smoke would pour from the exhaust but assured me that it would clean the carbon off. I have to say that I never had the nerve to try it, sold the POS instead.

[luap]

why do you want something to poor down the cylinders if your going to be rebuilding the motors? wont you be replacing the rings.new gaskets why not just pull the pistons off. 50/50 water simple green an heat takes the carbon build off easily

[KJ790]

I know it sounds crazy but a drag racer I knew back in the 70s told me his method. I had an old crappy Renault that would run on for 10 minutes after switching off. He told me to remove the air filter, start the motor and pour water into the carb! He swore that water would disolove the carbon buildup quicker than anything else. He said white smoke would pour from the exhaust but assured me that it would clean the carbon off. I have to say that I never had the nerve to try it, sold the POS instead.

Good way to hydrolock a motor and bend a rod or destroy the crank...

To the OP, why don't you just clean the pistons after you take them out of the engine?

[camelman]

I just use Seafoam after I scrape the pistons with a pocket knife.

[grcamna2]

I'm not sure if it's still available...but I have used an old product called "Firezone" oil; it did clean them up,but I'm not sure if it's still on the market.

[strynboen]

glass blast them..done it on mine..and valves and top..

[BobbyR]

I know it sounds crazy but a drag racer I knew back in the 70s told me his method. I had an old crappy Renault that would run on for 10 minutes after switching off. He told me to remove the air filter, start the motor and pour water into the carb! He swore that water would disolove the carbon buildup quicker than anything else. He said white smoke would pour from the exhaust but assured me that it would clean the carbon off. I have to say that I never had the nerve to try it, sold the POS instead.

Good way to hydrolock a motor and bend a rod or destroy the crank...

To the OP, why don't you just clean the pistons after you take them out of the engine?

That is an old trick and still used by mechanics in Europe on hi end cars. It is done with a spay bottle not a garden hose.  TAkes an awful lot to hydrolock a motor.

[grcamna2]

BobbyR ,
    Have you tried cooling down some of those hot babes w/ a spay bottle?; some of them are really hot.

[FuZZie]

I know it sounds crazy but a drag racer I knew back in the 70s told me his method. I had an old crappy Renault that would run on for 10 minutes after switching off. He told me to remove the air filter, start the motor and pour water into the carb! He swore that water would disolove the carbon buildup quicker than anything else. He said white smoke would pour from the exhaust but assured me that it would clean the carbon off. I have to say that I never had the nerve to try it, sold the POS instead.

Good way to hydrolock a motor and bend a rod or destroy the crank...

To the OP, why don't you just clean the pistons after you take them out of the engine?

That is an old trick and still used by mechanics in Europe on hi end cars. It is done with a spay bottle not a garden hose.  TAkes an awful lot to hydrolock a motor.

Lets also not forget water injectors used in some turbo and supercharged systems to control detonation (engine knock or pinging if you rather).
A garden hose is another story .....

[KJ790]

I know it sounds crazy but a drag racer I knew back in the 70s told me his method. I had an old crappy Renault that would run on for 10 minutes after switching off. He told me to remove the air filter, start the motor and pour water into the carb! He swore that water would disolove the carbon buildup quicker than anything else. He said white smoke would pour from the exhaust but assured me that it would clean the carbon off. I have to say that I never had the nerve to try it, sold the POS instead.

Good way to hydrolock a motor and bend a rod or destroy the crank...

To the OP, why don't you just clean the pistons after you take them out of the engine?

That is an old trick and still used by mechanics in Europe on hi end cars. It is done with a spay bottle not a garden hose.  TAkes an awful lot to hydrolock a motor.

Right, spritzing water into the intake and pouring water into the intake are two different things. If you pour a cup full of water into your intake while the engine is running you will almost definitely hydrolock the motor. I would just clean the pistons when they were removed.

[BobbyR]

BobbyR ,
    Have you tried cooling down some of those hot babes w/ a spay bottle?; some of them are really hot.

Dude, I sincerly wish I could. 

[FuZZie]

a cup, that would be about 240cc? OR about 1/3 of the volume of a 750 yea I think you'd have a good shot at breaking shat. 

[MCRider]

Soda blast after the fact. Clean, quick, environmentally friendly, water cleanup. Cheap to DIY...or...

http://forums.sohc4.net/index.php?topic=79458.0

[Xnavylfr]

I have to call a BS on hydrolocking an engine by pouring even a FULL cup of water in the intake. I've done it many times since I got my FIRST car in 1968.
You let the engine warmup to temp and slowly pour the water in the carb a little at a time, I usually hold the throttle open to about 2500 RPMs then rev a little each time I add water. Trust me, as soon as the cool  water hits the hot metal in the cylinders/pistons it will break up 90% of the carbon build up because you'll blow it out the tailpipe.. Same as HIgh Pressure spray with a STEAM gun on greasy cruddy parts you don't need any pre soak with any solvent or soap!!

Xnavylfr(CHUCK)

[chewbacca5000]

Wow!  Lots of great responses and some good tricks to boot!  Wish I had a better air compressor to drive my soda blaster that would be the cats meow.  The water idea is really interesting to me and should work on a running engine the same way you deglaze a cast iron frying pan.  I have a heavy 10+ lb frying pan that I pour water into after I finish frying up my moose steaks and it gets rid of all the burnt on mess.  I might give this a shot in the future.  For now a might try kerosene as I can pour it down the spark plug holes of a locked engine.  Maybe it will just all wipe off after several weeks of sitting.

Much Thanks for all the great responses!  If anyone has another way to remove carbon from parts I'd be interested in hearing it.

Thanks!

[BobbyR]

If the engine is stuck the preferred method here is to pour a 50/50 mixture of ATF and Acetone into the cylinders. It seems to penetrate better than Kero.

[chewbacca5000]

Thanks Bobby!  I'll give it a go.

[FuZZie]

I have to call a BS on hydrolocking an engine by pouring even a FULL cup of water in the intake. I've done it many times since I got my FIRST car in 1968.
You let the engine warmup to temp and slowly pour the water in the carb a little at a time, I usually hold the throttle open to about 2500 RPMs then rev a little each time I add water. Trust me, as soon as the cool  water hits the hot metal in the cylinders/pistons it will break up 90% of the carbon build up because you'll blow it out the tailpipe.. Same as HIgh Pressure spray with a STEAM gun on greasy cruddy parts you don't need any pre soak with any solvent or soap!!

Xnavylfr(CHUCK)

Yea this can happen chuck, on the compression stroke... think of trying to compress water, it works much like any other hydraulic piston.  I'm with you I think it would be rare and have never seen for myself. It would require at least 1 full cylinder and if some air was in it well it would just compress that air much like air in a brake line.

[ekpent]

I love how these threads get a life of there own.The guy wanted to know how to get a little carbon of the top of his little pistons and now we got garden hoses running through the engine. Well I guess thats one way to do it. ----------


PS-Bobby-Your advice is always +1 as our your pics-------

[Kanticoy]

Seafoam in a bucket, piston crowns down in said bucket, seal bucket, come back in the morning, and they'll wipe clean.  Works with heads too.  Use it all of the time.

[Xnavylfr]

I have in-depth KOWLEDGE of what a HYDRO-LOCK is , I spent 40+ years as an aircraft mechanic specializing in "WAIT FOR IT"  Hydraulics.  YES I agree it COULD happen ,but you would have to FILL the compression area capacity. The water turns to STEAM in a hot engine.
This situation changed completely when he said the engine was STUCK. USE THE SEAFOAM. or the ATF and acetone, either will work fine to help break it loose.

Xnavylfr(CHUCK)

[Rigid]

Seafoam in a bucket, piston crowns down in said bucket, seal bucket, come back in the morning, and they'll wipe clean.  Works with heads too.  Use it all of the time.

What does a "bucket" of seafoam cost?  They get $9.00 a bottle locally.