G'day

Remember, he was measuring the pH of the nitro he bought, not of the fuel he made. I agree, 1 is very acidic. Did you read the original article? Link above.

Cheers

Yeah I did read the original post on the Aussie forum, but I still think that the pH 1 is incredible for nitromethane production. I would tend to lean toward contamination at a the local packing company.
I don't think it would be at the chemicals manufacturing plant because such a high acidity will have a knock on effect on the overall plant operations. Pure nitromethane is however acidic, not neutral.

This however is an important post because nearly all fuel that we buy uses imported Nitromethane thats blended locally by a chemicals company that will also blend other chemicals. The opportunity for cross contamination is high if the facility does run-down blending and utilises the same piping for the other chemicals products. You think its unlikely that mistakes can be made but I have seen it at large and small operations.

Just a point to note: Any fuel is either slightly acidic or slightly basic. It will never be neutral. Hence most fuel companies whether gasoline, diesel or Jet (Kero) or oxygenate type fuel producers, add stabilisers to the fuel to limit the corrosion properties of the fuel as well the fuels own affinity for oxidation.

The majority of young modelers are being led by the model publications and the marketing folks' advertising into thinking that only the most powerful engines and fuel are worth consideration for their models. They actually behave as though they are racing against one another. P-shaw!

There was a time when low nitro was cool (environmental awareness) and engines burning little to no nitromethane in competition were considered "cool". Remember OPS, Picco and Rossi engines? Besides being cheaper to operate, the latter type of engines required more technical finesse to design and operate. I miss those days.


Ed Cregger

Ok group one more thing I saw on my instruction sheet with my MVVS 15Diesel, they state leave the piston at the bottom of stroke when storing this prevents any exhaust residue from being trapped (and moisture which can even come from the air which will condense some water out of the air when the engine cools) very good advice glow or diesel,no moisture trapped and alcohol even more to adsorb moisture this allows it to evaporate and leave the engine dry of course there is some oil still coating the engine but good insurance for any engine glow or diesel martin

the moral of the story is to run whatever anti corrosion you are using THROUGH the engine. Immersing the engine does nothing for it. So whether you use after run oil, diesel or kerosene distillates or heavier stuff like any polar molecule containing lube oil (motor oil included), run it through the engine and drain excess. The polar nature of the additives and the doublebonded molecules with paraffinic tails will adhere to the surface and protect it from corrosion. The trick is running through and drain.Anyone submerging engines is looking for trouble because nothing has drained especially the nasty stuff

Blah - Blah -Blah!


original quote attributed to: Eustice Baggs (Courage The Cowardly Dog).

My point being that after reading what everyone has espoused, including myself, I still do not see a clear and proven method of engine storage treatment. No one agrees with anyone else!


Ed Cregger

I have heard arguments before that we have "better" synthetic oils here, and might be true, but it does sound a little odd that there would be a difference now days when everything is being shipped all over the world and back. The quality of Nitro is an interesting idea, the price is much higher here (I would have to pay about $40 for one litre of nitro) and that might mean that we are used to a higher quality too. I will have to dig up some litmus paper...

Mr. Cox- that would be interesting but I think the high price is mostly based upon taxes in most countries.

Sounds like astrongacid with a Ph of 1. Sulfuric acid and weaker soloutions of HCL perhaps. I doubt nitro could degrade to that extent. Probably a bad batch,or the wrong chemical was poured into the jar.

It has a PH just below 7, it is basically neutral.  The burned byproducts are another matter.

actually its Acidly neutral, the pH is just below 7 remember...

chemically speaking anything below 7 is acid anything over is basic. Only 7 is neutral..


Ed, I agree blah blah blah. there is no right way. There is only science. The science says that in order to prevent corrosion you must displace the stuff causing the corrosion with something neutral or slightly basic.

Many neat synthetic oils tend to be slightly acidic hence they require the addition of basic additives to neutralise acids in the oil on the metal parts. This is why almost no synthetic motor oil is actually fully synthetic but a blend of mineral and synthetic components. Also hence why in RC engines, a blend of synthetics and castor is ideal.

you could even simply run your rc fuel through the engine with the glow plug removed and your finger over the plug hole. The pumping action removes the burnt stuff and replaces it with unburned fuel and oil thats far more friendly to the engine.

What is the PH of castor oil?
If you put your finger over the plug hole, why even take the plug out? Is it to put in fresh fuel through the plug hole? If you are doing that, why not just load it up with ATF or air tool oil? Why not just run FAI fuel, with no nitro since nitro in the big offender, Right? And, what is the PH of FAI fuel? What 2 stroke oil do you recommend for gas engines? (I had to add that last just to stir up the hornets nest some more). Thanks.

Regards,

Richard

There is no information on its PH level for Castor Oil, sorry: ref http://www.jtbaker.com/msds/englishhtml/C1500.htm
So then we wouldn't have any PH info for FAI fuel either as it is methanol and castor oil.
Yes FAI types of fuel is the way to go, no nitromethane in it. But here in the USA most modellers are hooked on using some nitromethane in their glow fuels. Usually many engines in the USA market are designed to use nitromethane in the glow fuel too. These engines typically do not run all that well off of no-nitro glow fuels. You would have to modify them to work better.

As for gasoline engines, use whatever 2 stroke oil you like a lot more to choose from. Since gasoline engines don't normally run nitromethane, you won't have any problems.
But years ago the special synthetic 2 cycle oils were known to be hydroscopic and tend to absorb moisture. A lot of guys found out about that the hard way, after parking their 2 cycle motorcycles for the winter. Then when they went to use them in the springtime, the bearings were all rusted out and bad. So it goes to show that synthetic oils do not really protect a engine from corrosion on the inside. So that led to the oil companies using blends with synthetic and mineral oils as one solution.

Now as for those gasoline engines that have been converted to run nitromethane and methanol, you have the same corrosion issues from nitromethane. But usually these engines are used in racing, so they get taken care of really well. If it is a 4 cycle gasoline engine, you need fire protection systems in the sump to prevent sump fires or put them out. That can get exciting if it happens to you and you are in the drag car sitting behind the engine when it occurs.

This is overly simplistic. You can have corrosion with a Ph of 7 or even way over 7. You can also have no corrosion with Ph well below 7. Not all acids eat all metals. And few do so above a Ph of 6 or so.

These are there to neutralise acids that are formed with the mixture of blowby, water, and oil. I know of no synthetics that are so acid that they need neurtralizing from the oil itself.

Castor oil has an acid value Pk of 1 to 2 which is very low. This means it only needs one or two milligrams of potasium hydroxide to neutralize it. Hardly worth worrying about.

Why can't they put a buffer in the fuel so that no matter what the burn products are they would be neutralized?

The one idea here that sounds sure fire is the diesel fuel. Does it ignite and run well enough in a glow engine to clean it out? I'm wondering what happens when you put something with 25% ether inside a four stroke and fire it up. Maybe it's fine. If so, it sounds like a great technique. If not, then keep a bit of no nitro all castor fuel on hand for a few second run at the end of the day sounds like the next best thing.

Jim

You know, many glow engines, especially those intended for little to no nitromethane in their glow fuel, will run off of model diesel fuel. Some engines run pretty good off of model diesel fuel other engines not so good. You would need to temporarily hook up neoprine or gasoline proof fuel lines to the engine before you tried it as the kerosene and or ether will eat up the silicone fuel lines.

Now you could just as easily simply run some FAI fuel through the engine (methanol and castor oil no nitromethane) and you would get the same effect. You would not even need ARO after you are done. So that might be a better solution. hard to say until some people try it for real.

I use some stuff called "ZIPP" in the heating trade and tried it in my engines to clean them out works like a charm ,clean and 100% dry, follow it up with some aro and no rust "ZIPP" can be had at your local heating supply house but be mindful it is a chlorinated solvent so keep it away from plastics.
for baked on residue use "grime solve" and rinse with "Zipp" the grime solve will turn plastic/ paint to mush but will cause baked on fuel to literally disolve on contact and leave behind nice clean bright shiny metal, don't tell anybody I told ya it's a trade secret, it's extremely good stuff ya just gotta be careful what ya spray it on both products will haze plastic on contact and turn it into a gooey mess if you leave it there long enough

The exhaust residues of diesels are bad too. A diesel engine should typically be left with the piston in BDC so that the bad fumes can get out of the cylinder in order to avoid rust. MVVS also recommends that the muffler is removed after each flight for the same reasons.

To avoid gumming up, due to the full castor diesel fuel, a bit of after run oil is also useful.

CAn we get some readings from different people here on their factory mixed fuels.
Iwill start. If I am reading the test strip right it came in at a 3.
The fuel was Morgans Omega 10% nitro with 4 oz added castor.

Nitro is the best CA remover there is

pH of castor oil, not sure but I can do some digging. Expect it to come out at slightly less than 7 though since its has a high concentration of long chain fatty acids.


I don; know why people do the strange things they. If I did I would have a cure for Crazy but I don;t so Crazy is still out there.

A few drops (like 10 maybe) down the carb, urn the engine over many times and then a few more drops of oil and turn it gain is all thats needed. Some fuel manufactures say no After Run Ol needed because they have Castor oil in. When running Omega I don't bother with after run oil. In fact I seldom bother with after run oil. If Ido, it's just the remains of the last top oil I used in my Golf, 10w 30 synthetic.

What you don;t want is to use methanol fuel as an afterrun oil. It has no lubricity (think engine seize), and contains oxygen (which promotes rust). FAIfuel has oil in it so i guess thats fine biut pure methanol , no no.

Generally I've had no problems either, but recently some guys in the club have had bearing failures on pretty new engines, including a Saito 100 and an OS 81a...expensive engines! There have been posts about others having failures too, so it makes me wonder if a better procedure might be needed. I like the idea of a short run with no nitro, all castor fuel because it would clean everything else out.

As for diesel fuel, I think it's the amyl nitrite (?...the ignition improver), isn't it? I think the kerosene, castor and ether are all fine.

Jim

I've always finished up my day's flying by giving the engines a run with methanol/castor and running them completely dry. In 50 odd years I've never seen rust. Oh wait...that's the only fuel I've ever used...oh never mind....

I don't bother to run the engine, Simply apply starter motor and flood it with fuel. then drain the fuel. All the nasty's should be out and all thats leftis the methanl with oil.

The methanol wil evaporate over a few hours leaving just the oil.

However Methanol contains oxygen so it can also promote corrosion if left behind for too long. At the end of the day, there is no fuel proof method to prevent corrosion entirely. On Planet Earth, water is everywhere