The crankshaft is installed in seven main bearings, the central one of which is a thrust bearing, responsible for the amount of axial play of the shaft.
Both main and connecting rod bearings have replaceable bimetallic liners with an antifriction layer on a steel tape.
Instead of separate main bearing caps, one common one is used with individual beds for each of the bearings, which gives the cylinder block additional rigidity.
The sealing of the crankshaft fit is provided by the front and rear oil seals, one of which is installed in the oil pump in the front part of the cylinder block, and the second - in the holder fixed to the rear wall of the block. The camshaft is also equipped with a front oil seal placed in the thrust plate of the shaft.
The material is taken from a web resource NissanBook.ru
The camshaft is driven by a toothed timing belt from the crankshaft toothed wheel. The belt tension is controlled by a special tension roller equipped with an adjusting spring and a locking (stop) nut.
All valves are equipped with internal and external springs with a shortened pitch of the lower coils. The twisting of the internal springs is made in the opposite direction in relation to the external ones. In addition, the direction of twisting of the sets of springs of the exhaust valves of the first, second and third cylinders is opposite to that for the sets of the remaining valves.
Hydraulic tappets make direct contact with the camshaft lobes and actuate cast rocker arms, which in turn control the valves.
Each hydraulic tappet, unlike the conventional one, is equipped with an automatic valve adjustment device that constantly maintains the valve clearance at zero.
The oil pump, located at the front of the cylinder block, is driven directly by the crankshaft.
The engine is hermetically sealed to the flywheel housing to extend the life of the starter and clutch. The lower part of the housing is provided with a plug for periodic drainage of water and oil accumulations.