\nIn a car’s power train, as pistons are pushed down, they cause the crankshaft to spin because they are connected to it via connecting rods. The top end of the connecting rod links to the piston by a wrist pin, while the bottom end of the connecting rod encircles a part of the crankshaft, offset from the centre, called a connecting rod journal. The journals are at different angles surrounding the centre, so as the cylinders fire in turn, pushing their respective pistons down, the crankshaft is turned. That turning motion is ultimately harnessed to cause the car to drive.<\/p>\n
\nWithin each junction between a connecting rod and connecting rod journal is a layer of soft material (call it the “wear layer”) whose inner surface is intended as a wearing surface against the connecting rod journal. The friction should ideally be minimized by proper lubrication. However, if that fails, the friction can grow rapidly and fuse the wearing surface to the journal surface.<\/p>\n
\nAt that point, the outer surface of the wear layer starts to “spin” against the wall of its containing fitting. However, the outer boundary of the wearing surface isn’t supposed to move relative to its neighbour; the friction between them can’t be absorbed. The engine will lock up or else that piston connecting rod may break off, etc: the engine needs immediate repair.<\/p>\n
\nA spun bearing will generally happen due to insufficient lubrication – either not enough oil or dirty oil – perhaps paired with extreme demand on the engine. Preventing it is one of many reasons to change one’s oil often.<\/p>\n
Source:<\/p>\n
howacarworks.com<\/a><\/p>\n hagerty.com<\/a><\/p>\n YouTube: Motorcarnut<\/a><\/p>\nJack of Oracle Tutoring by Jack and Diane,<\/a> Campbell River, BC.\n","protected":false},"excerpt":{"rendered":" Self-tutoring about autos: the tutor mentions the term “spun bearing.” In a car’s power train, as pistons are pushed down, they cause the crankshaft to spin because they are connected to it via connecting rods. The top end of the …<\/p>\n