Engine internals

Camshaft

Times the opening and closing of engine valves.

Drag to turn it Open in the 3D lab
Where it sits

In the cylinder head on overhead-cam BMW engines.

How it works

Shaped lobes act through followers or levers, while cam timing is synchronized with crankshaft rotation.

Think of it as

A rotating schedule that tells each door when to open.

Symptoms when it fails

Timing faults, top-end noise or reduced performance can involve timing, lubrication or valve gear.

Lifespan

Usually condition-based rather than a routine replacement. Lubrication, overheating and the exact engine affect wear.

Repair cost

Internal-engine work is usually labor-intensive. Diagnosis and the engine code determine the repair scope.

The BMW angle

BMW VANOS adjusts camshaft timing; it is different from changing valve lift with Valvetronic.

Used in

BMW petrol and diesel engines; petrol-only systems are identified individually.

Sources
Same system

Engine internals

Engine blockHolds the cylinders and supports the engine’s rotating parts.Cylinder headCloses the cylinders and carries the valves that control breathing.Cylinder-head gasketSeals combustion pressure, oil and coolant between the block and head.PistonReceives combustion force and moves up and down inside a cylinder.Piston ringsSeal combustion gas and control the oil film on cylinder walls.Connecting rodTransfers piston force to the crankshaft.CrankshaftTurns the pistons’ back-and-forth motion into rotation.Crankshaft main bearingSupports the crankshaft on a controlled film of oil.