Camshafts
Recent advancements in engine technology have brought about new camshaft designs. Most modern BMW engines use some form of composite camshafts which are assembled from individual components rather than machined from an solid cast iron blank. This technology not only provides a reduction in manufacturing costs, but also a considerable weight savings.
Scheme 857
| Index | Explanation |
|---|---|
| A | Intake camshaft |
| B | Exhaust camshaft |
| 1 | Drive flange |
| 2 | Flat for special tool |
| 3 | Shaft tube |
| 4 | Cam lobe |
| 5 | Output flange for vacuum pump |
| 6 | Reference for camshaft sensor |
| 7 | 3-point lobe for high pressure pump |
| 8 | Flats for wrench |
COMPONENTS DESCRIPTION CHART
The N63 engine has assembled camshafts of the type as used on the M73 engine. All components are shrink-fitted on to the shaft.
Scheme 858
The illustration shows the different components of the camshafts.
The drive flange, the wrench flats and the flats for the special tool are made from one single component. A three-point cam that drives the high pressure pump of the fuel system is additionally mounted on the exhaust camshafts. It is located after the first/fifth cylinder.
Another special feature of the N63 engine is that the exhaust camshafts for cylinders 2, 4, 7 and 8 produce a different valve lift curve than for cylinders 1, 3, 5 and 6. The exhaust valves of cylinders 2, 4, 7 and 8 open later, they have a shorter opening period and a smaller valve lift for even smoother engine operation.
Scheme 859
| Index | Explanation |
|---|---|
| A | Cylinders 2,4,7 and 8 |
| B | Cylinders 1,3,5 and 6 |
| 1 | Valve lift (mm) |
| 2 | Crankshaft angle (degrees) |
| 3 | Exhaust valve opens |
| 4 | Exhaust valve closes |
| 5 | Exhaust valve opening period |
| 6 | Intake valve opens |
| 7 | Intake valve closes |
| 8 | Intake valve opening period |
COMPONENTS DESCRIPTION CHART