Nissan:: Sunny:: Processing of a head of cylinders / valves

3.3.8. Processing of a head of cylinders / valves

Saddles of valves with wear tracks and an obgoraniye can be processed, with preservation of adjustment corners and width of a saddle. Otherwise the head of cylinders has to be replaced. Always process saddles of valves before achievement of a faultless type of a working surface. The saddle of the valve can be replaced by means of the ordinary press equipment of a workshop. For processing the mill is necessary for a valve saddle. Since the handling of this tool demands special experience, this work has to be performed in a workshop.

Check of a type of a working surface of a plate of the valve

PERFORMANCE ORDER

	1. The contact surface of a facet of the valve (1) has to be in the middle of the plate width of the valve and pass evenly on all circle.
2. If the plate thickness of the valve (2) is lower than limit of wear (boundary value), replace the valve.

Amount of processing of a head of cylinders

If deformation of a sealing surface exceeds extreme value of 0,1 mm, it is necessary to process a sealing surface of a head of cylinders.

Height of a new head of cylinders: 137,9–138,1 mm.

Prevention

The head of cylinders and the block of the engine, can be processed in the sum as much as possible on 0,2 mm.