Technical data

18
9
Crankshaft/main bearings
The crankshaft is forged from a high-strength
steel 42CrMo4 and weighs 21.63 kg. After
grinding the bearing points, the shaft is
nitrocarburized.
The colour codes of the main bearing shells
are stamped on the crank web of the first main
bearing.
Connecting rods
The forged connecting rods of the S65 are
made from the material 70MnVS4 BY. As on
the S65, the large connecting rod eye of the
connecting rods used on the S85 is cracked,
thus achieving an unmistakable parting joint
with outstanding fit accuracy. As on the NG
engines, the small connecting rod eye is
trapezoidal, enabling it to support the force
over a large area. The connecting rods weigh
582 g and are produced to a tolerance of ±
2 g. No classification is necessary in view of
this very close tolerance range. When
assembling the connecting rods and pistons it
is important to bear in mind that the
connecting rod is asymmetrical and, in the
same way as the piston, must be specifically
installed with respect to forward direction.
The one-sided reduction of the thrust collar by
1.5 mm per connecting rod serves the
purpose of shortening the lateral offset by a
total of 3 mm and therefore reducing the total
length of the engine by 3 mm. The installation
direction is indicated by two elevations on the
connecting rod.
1 - Main bearing classification (G = green; Y = yellow; V = violet)
2 - Asymmetry of connecting
rod