Naptha?

I doubt if it would do much, Bill. This is straight lye, with goop in it to keep it from sliding off of surfaces. It will saponify fats and oils, and it will attack some polymers and proteins (like the ones in your body cells), but it won't touch carbon.

If the problem is partially-burned castor oil with some carbon mixed in, it might work. But, chemically, it's no different from "heavy duty" version of Easy-Off oven cleaner. You might try that first. It's less hassle for small projects.

I've never had much luck finding a chemical way to get carbon out of an engine. There supposedly is some treatment but I can't remember what it is, nor have I tried it. When I did it, I used scrapers. Ugh.

BTW, don't use this stuff (or Easy-Off) on aluminum or galvanized steel. It eats aluminum and zinc for lunch. It's no problem on other platings, but chrome is porous, and it will get through it and attack the copper plating underneath, bubbling off the chrome, if you leave it on too long.

That's the voice of sad experience. d8-(

Tried the oven cleaner already, not so great. Sandblast would be interesting, but the shape of the pipe makes it impossible to really get inside with a normal nozzle. I'm actually desperate enough to be thinking of making a high velocity water jet with sand entrainment to try and scrape the gunk off "around the corner" of the chamber. Right now, I can get a reasonable cleanout only if I'm willing to spend hours fussing with it, and getting pretty grubby in the process. Must be a better way...

bill

Yeah, well, good luck. If you find something that works, let us know. I don't have to de-coke old British engine cylinder heads anymore, but it may be useful for something. d8-)

"Extrude-hone" comes to mind, forcing an abrasive paste/slury through the inaccessible passages. Perhaps that will spark some DIY ideas...

Alkaline degreaser will loosen/remove carbon deposits.

I used to soak Quincy 2-stage air compressor heads in it at a previous job, to remove the coked oil & crud from the internal passages before rebuilding & it worked very very well & even left the paint on them.

MikeB

It's a great product, but you'd really have to apply some imagination to use the principle for something like this.

Maybe someone with the required imagination will get involved. d8-)

I use the Zep Heavy Duty version (gray bottle). I have not found anything that works better.

If I want things *really* clean I do a two stage process:

1) Varsol to get the worst of it 2) Zep followed by successive hot water rinses.

Usually after this the piece will pass the Waterbreak test. Word of caution - if used on steel make the final rinse with distilled water. Delays the onset of rusting.

Michael Koblic, Campbell River, BC

(...)

Gaaah! Another naptha synonym: "Varsol? fluids are traditional solvents that are also known as mineral spirits or white spirits."

Thanks Michael

--Winston

You're really getting caught up in an overlapping lexicon. Varsol is a brand name, but it also became a sort of generic name for unbranded Stoddard solvent and similar types of hydrocarbon solvent. It was standard-issue paint solvent and cleaner, moderately slow-drying. It also is 50% of WD-40. An old-time hardware store in my town, now deceased, sold it from a tap. You brought your own can.

Mineral spirits, white spirit, Stoddard solvent, etc., are pretty much the same, unless you're a professional painter and are tuned into slight differences in drying speed. All of these closely-related hydrocarbons have similar characteristics. They're aliphatic hydrocarbons (relatively safe), sometimes with some aromatic hydrocarbons (very unsafe) in low percentages (making them safe enough for home use, more or less).

Naptha sold for painting use, known as Naptha VM&P ("varnish makers and painters), is not a precise product. Like the generic "mineral spirits," it covers a pretty broad range of volatility, and it may have small percentages of phenol and other dangerous crap in it. I think it's a bit more volatile than the usual run of "mineral spirits," but that's based on limited experience and long ago.

There is more, but my knowledge of chemistry taps out right here. I don't want to lead you astray. For your cleaning use, it seems unlikely that you'll notice any difference among these products, but maybe you will.

If you want a handy thing to try, give WD-40 a shot. As I said, it's 50% solvent that's in the Stoddard-solvent class, plus 15% mineral oil of some type, and the balance is propellant. If naptha works, WD-40 should work. Maybe.

(...)

I remember the local _Star and Bar_ gas station had a separate pump for 'White Gas'!

VM&P was the only stuff I found that would remove the rubber 'spots' left on my hardwood floor by 'throw rug' non-skid 'backing'. Left the floor shiny, and nice looking, it did. I used *lots* of ventilation.

Doubtless the VM&P I've used over the years has been a Dukes Mixture of leftovers from higher quality product. I never noticed, though. It always worked a treat.

In my misspent yout, I soaked the table of my sheet metal shear with WD-40 as a rust preventative. Oops. After the volatiles totally disappeared, I was left with a mottled waxy surface that *still* allowed rust spots to develop. I cleaned it off with some naptha :) and then, following an old trick gleaned from an ancient _Mechanix Illustrated_, I 'whooshed' on some dry graphite and rubbed it in with a cloth towel. The surface remains pristine and rather nice looking.

--Winston

(...)

This morning, I lit the burner and, in a bit, I was greeted by the musty aroma of burning Zep. Ooops. I want my naptha back!

:)

--Winston

Who and why? Coleman or Amazon? Cite?

That sounds like good old Christian Guilt.

-- Never underestimate the innate animosity of inanimate objects. --anon

Who cares? I'm just waiting for my fat check.

Then you asked the wrong question and didn't give us guessers enough info to go on. That's shameful, sir.

-- Never underestimate the innate animosity of inanimate objects. --anon

Oddly enough, the specialty Zep product I got was their Anti-Rust (5gal) that I use in the water table of my small CNC plasma cutter.

Minimum order: 1/2 a brush or $4,000, whichever is greater.

-- Never underestimate the innate animosity of inanimate objects. --anon

Try Simple Green. (Now in lemon scent, which I prefer.) It cleans burnt pine tars off tablesaw blades in 15 minutes. I'll bet it would work in an expansion chamber. A gallon might fill it. Tape one end and fill 'er up. You can prolly reuse it several times.

$6.99 at a Homey's Despot store near you. ($8.99 original)

-- Never underestimate the innate animosity of inanimate objects. --anon

(...)

Don't blame me, I forgot.

I'm wrapping up my tour of Alzeheimer's stage 7, remember?

(Took *over an hour* to replace the valve cover gasket on my older Camry this morning. Don't tell anyone.)

:)

--Winston

Consider the nature of the deposit - thermally polymerised vegetable oil

• carbon. If it was a drying oil (e.g. boiled linseed oil) + carbon black it would be a paint so for easy decoking, use paint stripper. Obviously don't use an alkali (caustic) stripper on aluminium parts, but dichloromethane (methylene chloride) based ones are safe on all metals found in an engine. Wash off any residue with methylated spirits (or if you used an alkali stripper just with water).

CAUTION: It will attack seals, gaskets and of course paint!

The only notable problem is that plastic toothbrushes don't last long in contact with dichloromethane based strippers, which is a pity as they are ideal for cleaning ring grooves, round valve seats etc.

I've seen a marine engineer (big ships!) burn out the carbon from a bronze exhaust system off a launch with a Stuart Turner two stroke engine - remove the exhaust from the boat, remove all the lagging, pour a cup full of petrol down it and shake well, build a bonfire round the whole exhaust and as soon as the flames coming out the far end died away, hook up a vacuum cleaner on blow! The result was an absolute inferno out of the manifold end and a dull red glow from the pipe. Apparently the trick is to rake the bonfire away from the exhaust once you have the glow and restrict the air supply as well if that doesn't control it as you DON'T want a BRIGHT red glow ;-) It actually took something like fifteen minutes to get the glow most of the way down the exhaust, at which point the engineer commented that it was now done, and he'd just let the bonfire burn out and it would be ready to reinstall the next day and it was also annealed as a side benefit!

I've never had the need or desire to try it myself . . . . YMMV!