25 Jul

Castor Oil . . . I Love the Smell of This Stuff . . . Can it Be Used in Our Cars?

Subject: Castor oil

Hi mark!  I love the smell of this stuff. I know John Sheally has used it. I see it on eBay sold as pure castor oil. Do you know if it can be used in our cars?

[Castor Oil was a basic ingredient in original Castrol Oils. In its raw form Castor Oil is the crap your parents gave you when you were feeling ‘poorly.’  I use a kitty litter like substance impregnated with ‘Castor Oil’ to combat the armadillos that are tearing up my lawn (ok, weeds . . .)  It really doesn’t smell all that good.   On the other hand, when it was originally used in Castrol Oil, the smell was intoxicating. 

Castrol is now a major lubricant brand and it has products for just about everything that requires lubrication on a Morgan.   Not sure of the chemistry on this new stuff but I am sure it is inline with all the other major brands (e.g. lots of synthetics and semi-synthetics). 

I doubt the current stuff has that ‘certain’ smell.   

From what I understand, the traditional Castrol Oil, the one that smells so good, is Castrol R.   A short bit on Castrol R follows, I took it off the web.  Mark]

Castrol R  (http://www.motorsportmagazine.com)

It is curious that we understand much better than its inventors the way Castrol R works, yet take it for granted.

In the case of Sir Charles Cheers Wakefield, later Baron Wakefield of Hythe, the sweet smell of success was more than a metaphor. You still catch the scent of the substance that made his company a household name in the early 1900s wherever older racing engines are exercised: that distinctive, heady perfume of Castrol R. Although castor oil, the origin of the smell, was still the purgative bane of many a childhood when C C Wakefield & Co introduced its Castrol range in 1909 (the name being a contraction of castor oil), to high performance engines on the road and in the air it was to become a more welcome part of the diet.

The story begins in 1899 when, having spent 15 years working for the London office of Vacuum Oil Company of Rochester, NY, later to metamorphose into Mobil, Charles Wakefield resigned his position as general manager and determined to strike out on his own. It was an auspicious time to be doing so. Within four years the Wright Brothers would take tentatively to the air, followed albeit somewhat belatedly by compatriot Samuel Franklin Cody at Famborough in 1908. A year later Louis Bleriot flew the English Channel and, five years after that, storm clouds over Europe would spur a period of unprecedented aircraft development effort. On the ground, progress was scarcely less momentous as the horseless carriage progressed from being a curiosity and plaything into an increasingly practical mechanism, as well as another vehicle of human endeavour and national rivalry.

Charles Wakefield wasn’t slow to realise that here lay both an important new market for lubricating oils and, just as significantly, a whole new marketing opportunity also. The world was agog at the daredevil exploits unfolding on land and in the air; having your product name attached to such derringdo was a golden opportunity to exploit what today we would call product placement. So Charles Wakefield determined to produce a new breed of oil for this new breed of machine, and make certain that the world knew of it.

Engine oil development, like engine development itself, was then in its infancy. Today’s world of multigrade and synthetic oils was a long way off. Prior to the sinking of the first petroleum well in 1859, engineers had had to use animal and vegetable fats and oils for lubrication, but these proved far from ideal at the extremes of temperature involved in the internal combustion engine. As every cook knows, fats and oils thicken when you put them in the fridge and leave gummy, varnish-like deposits when you heat them in a pan. This same behaviour in an engine made cold cranking difficult on startup, while oxidation of the lubricant at combustion temperatures could, literally, gum up the works.

Mineral oils relieved these limitations, even in their early forms offering a level of thermal and oxidative stability traditional lubricants couldn’t match. But they were far from perfect In particular they lacked what, at the time, was termed “oiliness”, the ability to adhere to metal surfaces in a thin, continuous film. Wakefield researchers found that whereas castor oil coated a hot metal surface, mineral oil tended to pool on it, leaving areas of metal exposed.

Today we have a much better understanding of why this happens. Castor oil is composed almost entirely of triglyceride fatty acids, of which ricinoleic glycerides form by far the largest proportion (typically around 86 per cent). Fatty acids are polarised molecules comprising an oily, hydrophobic (water-hating) head and a hydrophilic (water-loving) tail; the hydrophilic ends of castor oil molecules are adsorbed to the metal surface, leaving the oily heads protruding.

The result is that castor oil provides excellent boundary lubrication, much better than that achieved by early mineral alternatives. In hydrodynamic bearings, like crankshaft bearings, where a relatively thick layer of oil is established, this offers no benefits. But where the oil layer is thin — on cylinder walls and cam lobes, for instance — it ensures a higher level of scuff resistance.

Mixing castor and mineral oil therefore seemed a good idea in the early 1900s, but the two are not readily miscible. What Wakefield researchers discovered was that a surprisingly small proportion of castor oil — as little as 0.7 per cent — was sufficient to confer its high film strength on the mix, and thus Wakefield Motor Oil (Castrol Brand) was born. In fact, five variants were introduced initially for different applications, Castrol R being the flagship product intended for aero and racing engines. Wakefield & Co’s core business was — and in the immediate future, would remain — lubricants for the railways and industrial customers, but it was Castrol Brand that was to carry the company name to the four corners of the globe.

Success was almost immediate. In October 1909, Britain’s first aviation prize, the Inauguration Cup, was won by Frenchman Leon Delagrange using Castrol oil. Following which, on land and in the air, the litany of Castrol successes encompasses many of the most significant events in aviation and motoring history, including Britain’s winning of the Schneider Trophy three times in a row with the R J Mitchell designed, Rolls-Royce powered Supermarine S5, and most of the World Land Speed Records established during the highly competitive inter-war years. In the Great War, Castrol R even came to the attention of Kaiser Wilhelm II, achieving almost ‘secret weapon’ status when it was discovered that a captured British aircraft could operate at considerably higher altitudes than German equivalents due to its engine oil’s superior low temperature performance.

In the 1920s castor oil was removed from general motoring oils as mineral oil technology advanced, but its superior film strength ensured it a continued role in high performance engines. Only in 1953 was Castrol R superseded by R20, again containing castor oil but this time mixed with a semi-synthetic, and the successes began all over again. Mercedes-Benz immediately chose it for the advanced W196, Fangio scoring a first-time-out victory for both oil and car when he won the French GP in ’54. Even today castor oil remains the lubricant of choice in certain applications, notably methanolpowered two-strokes because of its complete miscibility with alcohol fuels. As a result you don’t have to go to a historic race meeting to catch that distinctive castor aroma. Appropriately, it can even be smelt where enthusiasts fly model aeroplanes.




2 thoughts on “Castor Oil . . . I Love the Smell of This Stuff . . . Can it Be Used in Our Cars?

  1. A couple of notes. Rotary radial engines in WWI aircraft (such as the Oberursel and LeRhone) had a stationary crankshaft and a spinning crankcase and cylinders. Air/fuel mix entered the engine via the hollow rear end of the crankshaft and castor oil was mixed with this to provide lubrication to the crankcase contents. Quite a bit of unburned castor oil exited the exhaust and ended up all over the pilot’s face. It was difficult to avoid ingesting some, and the reputed cure to still the bowels was a nip of brandy in a flask kept in the pilot’s kit.

    I’ve seen what a sticky mess is left all over the belly of the plane by use of castor oil in a rotary radial engine. Oven cleaner is about the only thing that will cut the polymerized oil.

    Also, as is well known, castor oil comes from the castor bean plant, Ricinus Communus, which is considered the most poisonous plant in the world. The highly toxic poison known as ricin is made from the beans. A lethal dose of castor beans for an adult is only four to eight beans. Remember the Georgi Markov, Bulgarian dissident writer who died in 1978 from ricin poisoning after being poked with a sharpened umbrella tip while walking down a sidewalk in London? A tiny, perforated metal pellet the size of a pin head was found in the wound.

    Castor beans are still sometimes found inside baby rattles. !!

  2. This also why scarves were de rigeur for WW1 pilots. Unsure whether silk was preferable to cotton or wool to protect face—possibly myth or affectation?

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