Volvo Penta TAMD61A, Workshop Manual

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Design and function
Con rods
The con rods have an I section, and are drilled for
pressure lubrication of the gudgeon pins. Since the
con rods have obliquely split big ends, they can be
pulled up through the cylinder bores during engine ren-
ovation.
The gudgeon pin bushes are made of steel and have a
bronze alloy lining.
On the 71 and 72 series, the con rods have trapezoid
small ends, to give a larger effective bearing area
against the gudgeon pin.
Camshaft
The camshaft is drop forged and induction hardened,
the cams are profile ground. The camshaft runs in
seven bearings. End float is determined by the cam-
shaft gear wheel, the shoulder on the foremost cam-
shaft bearing journal and the thrust washer screwed to
the front surface of the cylinder block.
Con rods with trapezoid small end (71 and 72 series).
Flywheel
The flywheel is screwed to a flange on the rear of the
crankshaft. It is statically balanced and fully ma-
chined. The flywheel ring gear is shrunk onto the fly-
wheel.
Torsional damper
The torsional damper consists of a hermetically
sealed housing containing a steel flywheel bob of rect-
angular section. The flywheel bob (damping ring) ro-
tates on a central bushing and is surrounded on all
sides by a viscous fluid (silicone compound).
Torsional damper
1 Crankshaft 6 Housing
2 Hub 7 Lid
3 Fluid space 8 Timing gear housing
4 Bushing 9 Seal ring
5 Flywheel bob