Captain Pugwash, I’ve heard about these problems quite a lot. I use Castrol R40 all the time and with regard to settling in the petrol tank I think there may be something in it. I rode my scooter (S2 TV175 engine) around this morning and there was frost on the grass and on windscreens. The old girl did seem to smoke a bit more than usual at first so perhaps the oil was starting to settle at the bottom of the tank. Time will tell on this score because I shall be riding her around whatever the weather.

Castrol R is a vegetable based oil that only really dissolves in what are called 'polar solvents' like ethanol, acetone, or a good one for washing it off is cellulose thinners. It is very reluctant to dissolve in petrol, which used to be a non-polar solvent, but is now a more vicious a solvent when it contains ethanol. It is equally reluctant to dissolve or mix with non-polar, hydrocarbon oils. Hope the pic ain't too small to see but this is the extent of carbon build up after running the engine for years on a mixture of Castrol R40, plain modern mineral, part-synth, fully-synth, and sometimes a mixture of one, or more than one other of the aforementioned. Despite what they say about Castrol R not mixing with other oils I believe this to be a misunderstanding. On four-strokes where people use Castrol R in their crankcases I can see why they wouldn't mix, and this is where the warnings come in; but on the total-loss, burn the whole damn lot in the combustion chamber two-stroke, it seems not to matter.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 Only in 1953 was Castrol R superseded by R20, again containing castor oil but this time mixed w,ith a semi-synthetic, and the successes began all over again.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.

It is curious that we understand much better than its inventors the way Castrol R works, yet take it for granted. Keith Howard redresses that balance Brought to you by Castrol Classic oils, Castrol GTX Classic 10w/40 is a high quality mineral engine oil for vehicles from 1978 to 1993. Produced to original formulation as specified in motor manufacturers’ vehicle handbooks. Containing anti-wear and anti-corrosion additives to provide high levels of protection necessary for older technology vehicles. 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. Castrol GTX Classic protects classic engines against problems like sludge, helping to extend the life of your mechanicals. With GTX Classic in your engine, there’s a great road ahead.

There is also a mass of oil left in the oil tank after it is drained so (IMHO) this would have to be taken off and washed out with cellulose thinners. Castrol POWER1 R 40 is a castor-based lubricant containing specially prepared additives to prevent rapid deterioration through oxidation. Its superior oiliness over mineral oils, imparted by the chemical structure of its components, gives it a great affinity for hot surfaces and provides excellent load-carrying properties which is an important consideration with highly stressed engines running at peak revolutions. 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. 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.