Volvo Crankshaft

Main journals: Cylindrical surfaces that ride in the block’s main crankshaft bearing shells. They establish the rotational axis.

Crankpins: Offset journals where connecting rods attach. The offset (half the stroke) defines displacement. Fillet radii at each side are critical, small radii amplify stress concentration and threaten fatigue failure.

Crank webs: Plates joining a main journal to the adjacent crankpin, carrying bending and torsion. Web thickness and counterweight integration determine stiffness. Web oil drilling must maintain residual strength.

Counterweights: Masses opposite each crank throw to balance reciprocating forces and reduce bearing loads.

Thrust faces: Axial control surfaces, usually at one main journal, that run against thrust crankshaft bearing halves. They limit end float and keep the timing set aligned. Grooves route oil and disperse heat.

Oil passages: Drilled galleries linking mains to pins. Some shafts use gun-drilled diagonal holes; others use external transfer via slingers. Chamfered exits on journals retain oil wedge formation.

Snout: Carries the crank gear/sprocket for timing, vibration damper, and pulley. The damper protects against torsional resonance that could confuse crankshaft sensor readings or crack fillets.

Flange: Bolt circle for flywheel or flex-plate. Concentricity and face runout must be minimal to avoid clutch judder and transmission input bearing overload.

Keyways/tapers: Provide an anti-slip location for the damper or timing gear. Poor key fit propagates fretting and can corrupt the crankshaft working principle via phase errors.

Reluctor/tone wheel: A toothed ring read by the crankshaft sensor to report crank position and speed for the ecu. Missing-tooth patterns provide an absolute reference for tdc.