As the lead in says, more than you ever wanted to know: Vintage Triumph Register - VTR 
Sort of off topic, but the assumption that "we" want to conserve oil may be faulty. As the manufacturers improve engine technology and the oil companies improve their oils to enable longer oil change intervals, old habits die hard - some folks can't let go of the 3K mile oil change, others want to do the "engine flush" thing, etc. Must really confuse the auto and oil company engineers.So if we want to conserve oil,a country that has no oil,ships its cars with old,'basic' oil,so you can get rid of it and conserve oil?