A good friend of mine used to scrap/break tractors and diggers.
He once bought an insurance write off, rubber tyred digger, which had been badly burned in a fire.
He was able to salvage some useable parts, from the machine in question.
However, it sat in his yard for a long time, after that, so thinking he wouldn't get sale for anything else off it, he decided to cut it up for scrap.
He had it buried in a heap of scrap, awaiting collection, when out of the blue, someone rang him looking for an engine crankshaft.
He was just about to say that he hadn't one, when he thought of the aforementioned burnt digger, which would have originally been fitted with the same model of engine and crankshaft, as the man on the phone was looking for. He remembered the engine on the burnt digger was complete and the crank shaft may have been salvageable. Thinking he might have a potential sale, he told the man on the phone, he would ring him back.
He went fishing in his scrap pile and dragged out the carcass of the burnt digger. Everything was looking good until he went investigating further, the burnt engine had no crank shaft!
The penny then dropped. Whoever owned the digger, must have had a problem with the crankshaft, and couldn't get a new one, or didn't want to spend a fortune on a new one, so staged a fire with the machine in question. My breaker friend said when he collected it, was given the impression that it had gone on fire outside it's owner's dwelling house, when it was being driven, but the fire got a hold on it so quickly, it had to be pushed/dragged off the road, out of the way, which was where my friend picked it up.