I was thinking the same thing about the effects, Tom.
Radial engines are pretty bad about burning oil, some are worse than others and Wright radials gained a reputation for burning and leaking the most. When the engine is sitting, the oil in the rocker arm cases along the top cylinders will drain into the top cylinders. Bottom cylinders get oil dripping off the connecting rods and crankshaft, which will slowly leak past the piston rings and accumulate in the cylinder head, if a valve happens to be open, it will drip into either the exhaust or intake manifolds. Starting these engines requires a very rich mixture, that creates a grey/white smoke. The colder the engine, the more fuel it takes to get it to fire, and that means even more smoke. As the cylinders begin to ignite the fuel, the oil inside the cylinders, exhaust manifolds, and any oil that is drawn in from the intake manifold begins to burn, creating blue colored smoke. More cylinders and larger displacement equals a larger plume of smoke. I find it to be a thing of beauty, I'm sure others nearly faint at the sight of all that smoke in the air.