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AB Volvo Penta / Diesel Engine TAMD71B
7 Technical description
Engine
These engines are four-stroke, straight six marine diesel engines with overhead valves. They are flu-
id-cooled and equipped with turbochargers. The inlet air to the engine is cooled by a raw water-cooled
charge air cooler (CAC) or air to air cooler after compression in the turbo.
The engines have piston cooling (oil-cooled pistons). The lubrication system has a full flow oil filter.
The cooling system is divided into a freshwater and a raw water system. The raw water cools the
freshwater system via a heat exchanger.
7.1 Cylinder heads
The engines have two cylinder heads, each covering three cylinders, and are made of special-alloy
cast iron. The cylinder head gaskets are made of solid sheet steel and have special rubber sealing
rings inside for oil and coolant channels.
7.2 Valve system
The camshaft is journalled in seven bearings and is driven by the timing gears. The camshaft actuates
the inlet and outlet valves in the cylinder heads via lifters, push rods and rockers.
These valves have double valve springs.
7.3 Cylinder block
The cylinder block is made of special alloy cast iron and cast in one piece. The cylinder liners are of
the wet type, can be replaced, and have a flame barrier which considerably increases the service life
of the cylinder head gaskets.
7.4 Crankshaft
The heavy-duty crankshaft is extremely strong and is journalled in seven main bearings. This shaft is
statically and dynamically balanced and tempered according to a special method (nitrocarburization).
This increases the fatigue strength and gives the bearing journals an extremely hard surface.
The journal at the front of the crankshaft has been ground to a polygonal shape. A polygon joint can
withstand the stresses from the vibration damper (extra pulley or disengageable clutch) considerably
better than a keyed joint.
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