Does anyone have a chart, or even an insight, into the British Army's lube oil specifications in WW2? The reason I ask the question is that there were a few experiments undertaken in changing the oils in tank turret hydraulic traverse mechanisms. For example with the Centaur, there were trials using M80 and C1117, My (limited) understanding is that the 'M' oils were motor oils, while the 'C' oils were gearbox oils, which tended to be of higher viscosity. Thanks in advance for any assistance.
There is an overlap between engine and gear oils in terms of viscosity. A straight 50 engine oil is similar to a 90 gear oil. The two standards are completely different... The British changed in 1943 from the M prefixes for engine type oils to HD detergent oils...yet another complication. There may be some clues here, or they may cause even more confusion, as they do amongst most vehicle owners.
Thanks very much, gents, that's very helpful. IIRC the 'C' gearbox oils had a higher mineral content in order not to break down under the higher physical stresses.
