Torsional Vibration Balancer; Connecting Rods; Pistons - Porsche Cayenne V6 2008 Service Information

Engine – Cayenne V8
1 - Piston (naturally aspirated engine)
2 - Piston (turbo engine)
Page 1.20

Torsional Vibration Balancer

A torsional vibration balancer is used to reduce torsional vibrations on
the crankshaft and to minimize component stress, e.g. on the belt drive.
A shock absorber with the very best damping characteristics was
selected because of the greater power impulses associated with direct
fuel injection engines.
The viscous shock absorber has a floating flywheel in silicon oil in the
housing. This allows the counter movement of the bearing mass to a not
quite evenly rotating crankshaft.

Connecting Rods

Compared to the 4.5 liter engine, the connecting rods are 2.4 mm
longer. This reduces piston lateral runout and is more efficient. The
connecting rod bearings are "lead-free" three-component bearings with a
diameter of 54 mm. Oil is supplied to the connecting rod bearings via a
Y-bore in the crankshaft.

Pistons

The pistons are designed as recessed pistons made of aluminum alloy.
They have an iron coating (Ferrocout) at the sides to improve friction
characteristics. The pistons are different on cylinder bank 1 and 2 both
in the Cayenne S and Cayenne Turbo. Another difference between the
pistons in the Cayenne S and Cayenne Turbo is that the combustion
cavities have different depths because the compression ratios of both
engines are different. The piston ring packages for the turbo and
naturally aspirated engines are the same.