The first aircraft start-up I ever recollect seeing, as a schoolkid, was a Dan-Air Airspeed Ambassador, with Bristol Centaurus radials, at Liverpool airport, starting up after an overnight stay.
The huge clouds of smoke (someone once wrote that it was LVPs for five minutes after an Ambassador started up) came from a basic design concept of a radial. The crankshaft is in the centre, with cylinders radiating all around. The crankshaft is as oil-tight as can be achieved with something which needs to flex, and handle thermal expansion, in other words not perfect. So as the aircraft stands and cools down oil inevitably creeps down from the centre into the lower cylinders. The Centaurus was a
sleeve-valve engine, and I am not sure if it had piston rings, but seemed more prone than most to this oil seepage. When you started up the oil was just burned off as the cylinders ignited, and this was the source of the smoke.
Oil consumption was apparently extraordinary compared to nowadays, lubricating oil was delivered in bulk bowsers. 56 gallon tanks on each engine on some types, and consumption that worked up to 5 gallons per hour, when it was time for an overhaul. Aircraft could be limited by lubricating oil range as much as fuel range. If you think about it, 56 gallons x 4 engines, and at 10 lbs per gallon (not sure) that is one
ton of lube. And by the time you got from Shannon to Gander most of that would be gone.
The last radial startup I saw was the DC-6 which came into London City for the airshow some 18 months ago, handled by guys who sometimes post on here. Nothing of the spectacle has been lost over the years !