Head-Mechanics

A crankshaft is a way to convert reciprocating linear piston motion into rotation. It does this through the crank pins/throws. These throws connect the pistons via connecting rods. These con rods connect to the piston though the small end and to the crank via the big end

End Bearing Journal    Pins      web's/counterweight        intermediate bearing

.A throw is 2 webs and a pin

The holes in the counterweight are drilled into the crank after it has been made. The drilled holes take weight out of the crank counterweight and therefore balance the crankshaft.

some crankshafts have the oil pump gear attached to the crankshaft and are driven via a chain. like the one above.

The crankshaft feed the bearings oil through holes drilled into the crankshafts. these holes can be seen here

The crankshaft surface must be completely free of any scuffs, pits or errosion. if any marks are present on the camshaft they must be polished or ground out. If grinding is needed then oversized bearing will need to be used. The crank pin measures a set distance. the bearing shells space the crank from the engine block. If the crank pin is reduced the bearing must compensate and become bigger to keep the correct spacing. below are some pictures of a pitted and scuffed pin and a polished pin.

We can fix it.