D.83
ENGINE
DESCRIPTION OF THE VALVE GEAR SYSTEM
The Navigator 1000 valve gear system consists of the crankshaft, the primary driving gear, the no. 1 valve motion
idler gear/sprocket, the no. 1 valve motion idler gear/sprocket shaft, the timing chains, the no. 2 valve motion idler
gears/sprockets and the camshafts.
This system allows the camshaft driving gear to be much smaller in diameter than a conventional timing sprocket.
The smaller size of the camshaft driving gears allows the overall cylinder height to be reduced. The primary driving
gear and the camshaft driving gears are of the scissors type. This allows the elimination of backlash and the
reduction of mechanical noise.
In this system, the angular position of the sprocket teeth on the no. 1 valve motion idler gear/sprocket relative to the
primary driving gear varies between the compression and exhaust top dead centres.
The figure below shows the positions of the primary driving gear and of the no. 1 valve motion idler gear/sprocket
when the piston in the front cylinder is at each of the two top dead centres. The difference between the compres-
sion and the exhaust top dead centres as seen on the gear, is in the position of the no. 1 valve motion sprocket.
While the meshing teeth of the no. 1 valve motion idler gear continuously change at each revolution of the crank-
shaft because the number of teeth of the primary driving gear and the no. 1 valve motion idler gear/sprocket is
slightly different, the sprocket teeth will take either of the two positions shown in the figure below relative to the
primary driving gear. Each of these two positions occurs alternately at every revolution of the crankshaft.
REAR INTAKE
CAMSHAFT
REAR EXHAUST
CAMSHAFT
REAR NO.2 CAM DRIVE
IDLE GEAR/SPROCKET
CAM CHAIN
NO.1 CAM DRIVE IDLE
GEAR SHAFT/SPROCKET
FRONT INTAKE
CAMSHAFT
FRONT EXHAUST
CAMSHAFT
FRONT NO.2 CAM DRIVE
IDLE GEAR/SPROCKET
CAM CHAIN
CRANKSHAFT
PRIMARY DRIVE GEAR
(SCISSORS GEAR)
NO.1 CAM DRIVE IDLE
GEAR/SPROCKET
Summary of Contents for Navigator
Page 5: ...A 1 GENERAL INFORMATION A Section ...
Page 9: ...B 1 MAINTENANCE B Section ...
Page 45: ...C 1 INJECTION AIR INTAKE SYSTEM C Section ...
Page 118: ...C 74 INJECTION AIR INTAKE SYSTEM ...
Page 119: ...D 1 ENGINE D Section ...
Page 199: ...D 81 ENGINE CAMSHAFT CYLINDER HEAD ...
Page 204: ...D 86 ENGINE VALVE TIMING DIAGRAM FRONT FRONT CYLINDER TDC OF COMPRESSION STROKE ...
Page 239: ...D 121 ENGINE Location of thicker 2 0 mm driven plate ...
Page 269: ...D 151 ENGINE CRANKCASE GEARBOX CRANKSHAFT CONNECTING ROD ...
Page 277: ...D 159 ENGINE ...
Page 297: ...D 179 ENGINE ENGINE LUBRICATION SYSTEM ...
Page 298: ...D 180 ENGINE ...
Page 299: ...E 1 SUSPENSIONS AND WHEELS E Section ...
Page 324: ...F 1 BRAKES F Section ...
Page 337: ...F 14 BRAKES ...
Page 338: ...G 1 ELECTRICAL EQUIPMENT G Section ...
Page 340: ...G 3 ELECTRICAL EQUIPMENT ...
Page 375: ...G 38 ELECTRICAL EQUIPMENT ...
Page 376: ...H 1 ENGINE COOLING H Section ...
Page 390: ...I 1 SPECIFIC TOOLING I Section ...
Page 391: ...I 2 SPECIFIC TOOLING ...
Page 393: ...I 4 SPECIFIC TOOLING ...
Page 394: ...L 1 TORQUE PRESSURES L Section ...
Page 400: ...M 1 INDEX M Section ...
Page 405: ...M 6 INDEX ...
Page 406: ...M 7 INDEX ...
Page 407: ...M 8 INDEX ...