60
Crankshaft
The crankshaft is either nitro-carburized or induction-
hardened (both alternatives exist). It has a new rear 14-
bolt flange against the flywheel (previously 10 bolts).
The crankshaft is single-piece forged in special steel.
The bearing surfaces are nitro-carburized to increase
strength and reduce risk of cracks.
The crankshaft has seven main bearings. Each big-end
bearing is placed between two main bearings. The
counterweights on the crankshaft are there to even out
operating surges so that torque is evenly spread out.
Up front the crankshaft has a polygon hub to which the
vibration damper hub is fixed. The main bearing and
big-end bearings consist of lead-indium plated and
lead-bronze lined steel shells.
Vibration damper
To further its damping qualities, the DH10A engine has
been given a more robust, built-in vibration damper.
The timing gear cover has had its shaped re-designed to
suit the new vibration damper.
The vibration damper consists of a housing containing
a rectangular damper ring, which is surrounded by sili-
cone oil, that acts as a speed buffer between the damper
ring and the housing. Since the housing is fixed to the
crankshaft, the speed buffer has a dampening effect on
crankshaft oscillations. The vibration damper is placed
on the inside of the timing gear cover in the figure.
Sound baffles
The engine timing gear cover and oil sump have been
fitted with sound baffles. These are built up of two
plastic layers with an intermediate damper layer of
plastic/rubber.
Crankshaft movement
Differences compared to THD104
Flywheel
The flyhweel has 14 holes.
Connecting rods
The connecting rods have trapezoidal gudgeon pin
ends.
Pistons
In design the pistons have been adapted to the trap-
ezoidal connecting rods. The shape of the combustion
chamber has been altered, resulting in altered compres-
sion ratio. Altered, too, are the specifications for the
piston rings.
Sound baffle for timing gear casing
Sealing strip
Sound baffle cover
Sound baffles for oil sump
