How to clear soot from inside exhaust manifold (1.6TD)????

[towns]

I just got my head back today from being rebuilt and I wanted to clean the inside of my exhaust manifold before i put it back on.  It has a buildup of carbon/soot over the whole inside surface.  So, what is the best way to remove this carbon/soot buildup?  ideas?

Thanks

[fspGTD]

If you want to make it really clean, really fast, the best way is with a die grinder.  Chuck up a standard abrasives cross buff

and run that through your runners two or three times.  These do an amazing job of stripping all the carbon build up off the metal walls very quickly and effortlessly without removing any metal.

If you've got a die grinder but are looking for a cheaper or quicker solution, go to your local hardware store and buy a 1/4" steel rod.  Hacksaw a slot in the end of it, and then compress and insert a strip of 3M scotchbbrite into that.  Your setup would look like this (except instead of emery cloth strip as pictured, you would have a strip of scotchbrite):

Another name this slotted rod is often called is a "flapper stick".

If you have no die grinder, you must get by with manual hand-cleaning methods.  Removing carbon by hand is a real tough job, but you should be able to easily at least get most of the thick, light & fluffy build-up off by just running it under some soapy water and scrubbing it inside with a small brush.  A pipe cleaning brush, with bristles sticking out on all sides might prove useful for this, or a small stainless steel wire brush that can reach into the ports may be helpful.  After drying, use a strong solvent and paper towels for getting some more of the carbon out.  You can ram them in and out of the ports pretty far by grasping them with some long needle nose pliers.  Removing carbon deposits is a very nasty job.  I'm sure there are other ways, these are just some ideas for you.

If you are interested in preventing the carbon from sticking again in the future, consider polishing the walls of your exhaust ports so they are so smooth that carbon won't be able to easily stick to them.  Good luck.

[towns]

Thanks for the thorough reply!  I didnt even think about using my grinder.... :?  I'll see how that goes.  Thanks again  

[tackered]

5400 RPMs.

[GTD.]

I'm planning on "steam cleaning" mine when I put it back on the road in a similar way to the old water decoke trick used on petrol cars.

On a petrol car you get the engine nice and hot then take off a vac advance pipe that feeds off the inlet add a straw and a bottle of water and let the engine inlet vacume suck the water into the engine, where it flash boils inside the combustion chambers decoking the combustion chambers and exhaust manafold.

On my TD I was thinking of disconnecting the pipe that goes from the inlet manafold to the LDA then using a windscreen washer bottle/pump to pump water into the inlet as having no throttle butterfly means no vacume, and hopefully the water will flash boil in the combustion chambers, cleaning the engine out

I've already carried out the "Italian Tune Up" but I didnt get any visible black smoke and the the engine governer kicked in around 4000 rpm, though my engine has only done 65000miles (91 SB engine)

[Maarten]

On my TD I was thinking of disconnecting the pipe that goes from the inlet manafold to the LDA then using a windscreen washer bottle/pump to pump water into the inlet as having no throttle butterfly means no vacume, and hopefully the water will flash boil in the combustion chambers, cleaning the engine out

DO NOT POOR LIQUID into the intake... the high compression of a Diesel and non-compressable liquid will destroy your engine in a snap!

[GTD.]

Its not liquid, If the engine is hot enough by the time it reaches the combustion chamber it instantly turns in to steam which is a compressable gas, also you dont want the turbo boosting at the same time either so that should give you a bit more leway so you dont end up hydralocking the engine, basically its water injection without the high powered pump as you want the water to flash boil on entrance to the combustion chamber on the inlet stroke of the combustion cycle

[Maarten]

I still think it is risky business... every heard an engine runaway?

and by the way, steam is not gas

[GTD.]

In science and engineering "steam" refers to water in its vapor
state.  You boil liquid water, the resulting vapor is steam.

[Black Smokin' Diesel]

But the resulting steam still isn't a gas, even if it can be compressed.

[QuickTD]

By my calculations it will take just over 17ml of liquid in a cylinder to lock a 1.6 diesel solid and bend the rod. It doesn't matter if it has turned to steam or not, if 17ml of liquid entered the cylinder, it will be 17ml again when it is compressed.

 On a gasser it would take closer to 50ml in any one cylinder to destroy the engine. As you can see the margin for error with the diesel is significantly smaller. Liquids can also pool in the manifold/intake system and be injested in large "gulps" when the engine speed is raised, so small amounts are often no safer than large amounts. Add liquid to the intake at your own peril...

[zyewdall]

But the resulting steam still isn't a gas, even if it can be compressed.

Uh.. How do you define gas?   I don't think the pressure would be high enough for it to be supercritical, so that means it's either gas, or a constant boiling mixture of gas (which is the steam portion) and liquid, right?

[watsongs]

Throw the manifold on your BBQ grill - let it get nice and hot.  Dump it in a 5 gallon bucket of water - the carbon will flake right off.  I used to do that to clean out the burners on my kero boat stove, so I tried it on my exhaust, and it worked pretty well.  Very labor unintesive, as opposed to the die grinder job.

 You can also get, for about $15 at a restaurant supply store, a can of CarbonOff spray cleaner, used to clean up pots & pans.

[Rat407]

If you have it off the car, couldn't you bead blast it?  My exhaust manifold cleaned up nice in our bead blaster at work.

[dieselweasel]

I don't know why you'd bother cleaning the carbon off the inside of the exhaust manifold...it's not harmful and will just carbon up again anyway.  Also what's the sense in trying to decarbonize a diesel engine?  There's no way that carbon deposits on pistons that cause cylinder wear can be removed with steam.  It makes sense in a gas if carbon buildup is causing pre-ignition.  

As for steam not being a gas...I don't know what to say.  I think the first thing you learn in science class at school is that there are three (actually four) states of matter:  solid, liquid, gas and plasma.  

Ice=solid H20
Water=liquid H20
Steam=gas H20