Also, the British used oil as a contributor to engine cooling as well. For example, the 70 hp 2.25 litre petrol engine in my 1973 Land Rover (an engine that was designed as a diesel in the 1950s), has a sump capacity of two gallons of oil. This is way more than is needed for lubrication alone.
I don't know if these high sump capacities and cooling function of the lube oil contributed to higher oil use or not.
Of course, the British were the first to discover the many benefits of what became known as the "Total Loss" lubrication system. Perfected in engines like the Rolls Royce Merlin that was used in the Supermarine Spitfire, the total loss oil system was quickly adapted by the British car industry. The theory behind the system is simple. If the engine is designed to leak oil, the operator will have to be pouring new oil in on a regular basis. Thus, the oil in the engine will remain much cleaner than if the engine didn't leak and the same oil stayed in circulation throughout the oil change interval. The British automotive industry used this system with great success and reliability until the car manufacturers began being acquired by foreign companies who began using their own engines in the cars. When Land Rover, for example, was acquired by BMW, they stopped using the Rover-designed and manufactured engines which experienced negligable engine wear due to the continuous replenishment of dirty oil with clean oil and substituted BMW engines, which, while they didn't leak, had very long oil change intervals and at 150,000 miles or so suffered from severe crank and cam bearing wear. The old Rover engines, like the one in my Land Rover, were barely broken in at 150,000 miles.
The Ford or Englane Dorset diesel that was marinized by Lehman is a prime example of an engine designed from the outset with the Total Loss lubrication system.* Leaks oil very nicely, and typically goes 12,000 to 14,000 hours (according to American Diesel) in recreational boat service before needing an overhaul.
Surprisingly only one US vehicle manufacturer recognized the value of and adapted the British Total Loss lubrication system, and that was Harley-Davidson. Sadly, they no longer use this system.
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-- Edited by Marin on Tuesday 1st of November 2011 02:14:02 PM