Perkins 1106C Genset Systems Operation Testing And Adjusting page 8

8
Systems Operation Section
Pistons, Rings and Connecting
rods
Illustration 6
The pistons have a Quiescent combustion chamber
in the top of the piston in order to provide an efficient
mix of fuel and air. The piston pin is off-center in
order to reduce the noise level.
The pistons have two compression rings and an oil
control ring. The groove for the top ring has a hard
metal insert in order to reduce wear of the groove.
The piston skirt has a coating of graphite in order to
reduce the risk of seizure when the engine is new.
The correct piston height is important in order to
ensure that the piston does not contact the cylinder
head. The correct piston height also ensures the
efficient combustion of fuel which is necessary in
order to conform to requirements for emissions.
The connecting rods are machined from forged
molybdenum steel. The connecting rods have
bearing caps that are fracture split. The bearing caps
on fracture split connecting rods are retained with
Torx screws. Connecting rods with bearing caps that
are fracture split have the following characteristics:
•
The splitting produces an accurately matched
surface on each side of the fracture for improved
strength.
Crankshaft
Illustration 7
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The crankshaft is a chromium molybdenum forging.
The crankshaft has seven main journals. Thrust
washers are installed on both sides of number six
main bearing in order to control the end play of the
crankshaft.
The crankshaft changes the linear energy of the
pistons and connecting rods into rotary torque in
order to power external equipment.
A gear at the front of the crankshaft drives the timing
gears. The crankshaft gear turns the idler gear which
then turns the following gears:
•
Camshaft gear
•
Fuel injection pump and fuel transfer pump
•
Lower idler gear which turns the gear of the
lubricating oil pump.
Lip type seals are used on both the front of the
crankshaft and the rear of the crankshaft.
A timing ring is installed to the crankshaft. The timing
ring is used by the ECM in order to measure the
engine speed and the engine position.
KENR6931
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