flybyjohn

My Feedback: (2)

I have a couple ABC engines to break in and the instructions call for 10% nitro and 20% castor oil. I have 10% fuel but oil content is 18% synthetic caster blend. I was thinking of adding enough castor to it to get 20% caster. Our club buys fuel in bulk but they do not have any full castor oil blends. Will adding castor oil work and if so where can I get it from. I was looking online and it looks like walgreens and cvs sells 100% caster oil for laxative. Is this the same stuff we use for rc?

ArcticCatRider

My Feedback: (6)

It will do in a pinch but it isn't the same. I don't think medicinal castor is de gummed like ours is.

You can buy it at a hobby shop. Sig makes "AA Castor" oil...sells it in quarts I think

w8ye

My Feedback: (16)

If you can take the castor oil internally (USP) it is safe to use in your engine.

However, it is usually cheaper to buy the Sig Castor oil

Looking on the Internet the castor per gallon seems to sell from $22 to over $55 depending on who you buy it from

Bax

My Feedback: (11)

You can use Klotz BeNol:

KSFP1175 BC-175 BENOL 2-STRKE CASTOR PT US$7.76

earlwb

If the medicinal castor oil is pure and hasn't had things like sugar added to it, you can use it in the glow engines. Some brands add stuff to it in an effort to make it taste better. it is a strong laxative.
But that would be for when you are out and need some in  a hurry as it is more expensive to buy it.
Many of the larger hobby shops usually have the SIG brand castor oil in stock. it comes in quart bottles.
Klotz also sells it in larger quantities too.

Campgems

Check the percent of oil mix. There is usually a good percentages ofCastor in the blended oil. Iwouldn't take the total oil mix much above the 22% mark.The engine really doesn't run very well above that percent.

When I fist started back into the hobby, Ihad the same question you did. I went to the drug store and bought a very expensive 40z bottle of Castor. I was going to use Omega 15% fuel and the overall oil mix was 17% at the time, it think they now quote 18%, Imade a spread sheet to calculate how much Castor to add to the the "Total" oil content up to the 20% in the manual. The Omega was a 70%/30% mix of synthetic to Castor. The 4 oz of Castor to a gallon of fuel brought up the overall oil to 21.9% and the synthetic/ Castor blend was 51% / 49%. Given the amount of Castor needed and the cost of the shipping a gallon from Sig and then what do you do with the left over, the expensive drug store stuff made a good choice.

Imodified the spread sheet a little so I could see the results of blending two fuels together, IECool Power FAI and Cool Power 25%. Or any other two fuels or components of the fuel.

Send me a PMif you would like a copy of the spread sheet. It is very simple.

Don

jeffie8696

Got to Wallyworld, buy the castor, dump it in your fuel and break in your engine. I do it all the time. Just make sure it has no added sugar.
Ifly my planes with the entire gallon of break in blend before I consider it broke in.

pe reivers

The more oil hurts performance is bullocks.
Some racing engines perform best at 30% castor. They just need larger tanks than permitted, so in some classes racers try to cut on oil as much as possible and have as much energy as possible in the tank so they can i.e. run more laps between refilling, which makes up for the loss in power.
Medicinal castor should be as pure as possible, and have no other stuff added. Degumming to me sounds like sell talk only. What is taken out of the pressed oil to make it "degummed". Does it still have the same emergency lubrication properties? Does it still mix with fuel as well? Is there less carbon after the same amount of running? Does it prevent the gum deposit on the piston skirt that necessitates a total cleaning once in a while?
I found medicinal (AA) castor to be as good as any.

earlwb

The degradation in performance as the oil percentage in the fuel increases isn't from the oil as much as it is the reduced amount of methanol in the fuel. As you increase the oil percentage you have less of the combustible methanol in the fuel. But you have to get above 40% before it becomes really noticeable. I remember someone posting a data list showing that a engine didn't degrade all that much in performance until the oil percentage was 40% or greater.

As Pe Reivers stated, higher oil concentrations don't really hurt anything. The early model airplane glow fuels ran 33% castor oil amounts. Later 25% was the common percentage of oil in the fuel. After that 20% became the defacto minimum oil percentage in glow fuel. Nowadays it is 18%. For older lapped piston, bushing crank engines use 25% oil or at least 20% oil in the fuel. The engines were designed back in the day when more oil was in the fuels and castor oil was the only lubricant available.
More modern ABC types of engines with ball bearing supported crankshafts can do well with lower oil percentages around 14% to 18%. Some fuel manufacturers like Fox manufacturing make special break in fuels with 25% castor oil in it.

But one thing to note is the smaller the engine the more oil it needs. The little 1/2a engines need 25% oil in the fuel, engines like the .010 and .020 may do well with 30% oil in the fuel. But as the engine gets ever larger and larger in size it needs less oil. A large engine can run on as little 12% to 14% oil content in the glow fuel. It is a factor of the surface area in proportion to the engine displacement as the engine displacement increases. The main limiting factor is whether the engines have a bushed connecting rod or a needle bearing connecting rod. Engines with needle bearings on the rod can run oil ratios down to 50:1 or so.

But there are some exceptions, the small .10 to 18 size car racing engines usually use a car glow fuel that has around 14% oil in it. This is for performance. Since the car engines are designed to run with less oil, tend to wear out fast due to their outrageous RPMs they turn, and the dust and dirt  they suck in, the low oil percentage is not a factor. So they go for performance. The 3.5cc car engines are in the same category too.

jeffie8696

SIG still makes 20 and 25% lube all castor fuels. Iuse them all the time.

w8ye

My Feedback: (16)

You lucky dog - You can drive over there and pick it up

The rest of us are burdened by Hazmat charges

jeffie8696

Four hours round trip , Ihave to make it part of a necessary trip doesnt happen very often.

w8ye

My Feedback: (16)

I get my Wildcat at Toledo every year when they have the model show. Good prices and no Hazmat fees. It is about 100 miles there.

downunder

But that's what the needle valve is for. Add more oil so open the needle a little so the same amount of methanol/nitro can get into the engine. Hey presto, same power .
As Pe said, with more oil you then have less combustible fuel in the tank which reduces flight time by an insignificant amount but it's the combustible fuel available that you tune the engine to, not the oil.

Castor marketed as "degummed" is just advertising hype because all castor is degummed as part of the refining (purifying) process after the oil has been extracted from the beans.

1QwkSport2.5r

So I'm at about 10 hours round trip.. For me, its almost a wash to drive there or have it shipped. I want to get some all-castor fuel but nobody will stock it locally and Sig is a bit cheaper than Fox (and within driving distance). Sadly enough, its about 10$ more to drive there than to have it shipped (based on a 2 gallon purchase - the all castor fuel is only sold in gallons)

gkamysz

My Feedback: (19)

Many castor based fuels contain an additive derived from castor (some sort of ester) that helps prevent carbon and gum build up. Most motorsport castor oils also contain it. I've sen a few that specify they do, some say so indirectly, but I would guess that most are using it. So while good virgin castor burns clean and varnish free a fuel or oil could run cleaner with the use of additives and still be mostly castor oil or marketable as such.

Motorcycle shops carry the expensive stuff. Maxima Castor 927 burns very clean.

Greg

jeffie8696

Ihave been trying to find the best deal on castor for years. It is OK to get it from SIG but if you only need some for a single gallon to break in an engine it is so convenient to grab a small bottle at WallyWorld for $2.50.

pe reivers

Maybe off topic
In Diesels, I have run several tests with different oils. Let me share:

Fully synthetic two stroke oil (for gasoline engines). Readily available.Does not mix with methanol
The oil mixed well, probably due to the lamp oil and ether in the fuel. 20% mixes in a .15 diesel ran excellent, but so did 10%! Never ran long enough to test engine durability in those lean mixes, but I would not be surprised to find no wear. The engine always felt well lubricated, but looser at room temperature due to lack of oil thickening.

GoKart racing oil (castor/?oil mixwith additives). Readily available.Mixes wellwith methanol
The oil was less sticky than castor, but in general could be mixed well, and performed well from 15% to 35% oil. same as above.

SAE50 engine oil. Readily available, does not mix with methanol.
Inferior results, lots of carbon. This oil always has been noted as a valid replacement for Castor. Not in my book. All the worn diesels I checked out had used SAE50 oil. Castor lubricated engines just wear out the lower connecting rod bearing, but not the liner/piston. Let this oil be used where it belongs. In the crankcase of a 4-stroke engine.

TimBle

The fuel you have is more than adequate to use in your engines. That 2% volume will make no difference.

Sport_Pilot

Actually AA castor has no gum. If it is degummed then it was A castor or worse and chemically treated to remove the gum. So degummed is actually inferior. Gum is not the varnish, or the congealed oil after it sits in the engine for years (something the marketers want you to think). Both of these are forms of oxidation. Gum will be slightly green and may even have poison, so it better not be there.

hsukaria

That castor oil exhaust leaves a big slime puddle when bench running though. I've had a lot of "fun" cleaning the goop off my old 4-Star when I used the Fox all-castor oil for break-in a few years ago.

TimBle

Degumming is a process of castor oil production. Anyone who think Castor Oil is pressed and botteld is sadly mistaken.

Castor oil is made by drying and cooking the ripe seeds and allowing them to split open. The cooking allows the protein to coagulate in the seed to ease separation.
They are then passed through a press where around 50% of the oil is removed. However theres still more oil in the seed casing so the cake (residue matrial)  is moved to a solvent extraction processor using either Heptane or hexane.
In the mean time the oil extracted from direct pressing is filtered throw a settling process and degummed to remove phospholipids and aqueous phase lipids from the oil. This is important as these are regarded as contaminants.

Neutralisation ( to remove fatty acids) is another step in the refining process and this done via either Chemical (alkali) or Steam stripping.

Then you have castor oil thats ft for use. I believe you have a special pharmaceutical grade in the US called USP?

Although Castor is wonderful lubricant, it still polymerises under temp and pressure creating varnish that can kill a ringed engine. A mix is prefered, syn to castor

jeffie8696

Iuse a blend in all my engines after break in . No problems so far but Iprefer an 18% as minimum.

hsukaria

So, when is it necessary to use full castor oil fuel for breakin? Some manufacturers recommend that (such as Fox)? With the exception of 1 engine, I broke-in all my engines with 5% castor/~15% synthetic. Now I remember my old Irvine engine recommended 0% nitro for breakin. I ran the first gallon at 0% nitro. That engine is still excellent after 16 years.

TimBle

if you'like to coat the entire inside of your engine with hard varnish then use a full castor fuel mix. No problem for an ABC but murder to a ring engine