Nissan Maxima QX

since 1993 release

Repair and operation of the car


Nissan Maxima QX
+ Cars of the Nissan Maxima brand
+ Maintenance instruction
+ Settings and routine maintenance
- Engine
   + SOHC engines
   + DOHC engines
   - General capital repairs of the engine
      General information
      Check of pressure of oil
      Check of compression pressure in cylinders
      Diagnostics of a condition of the engine with use of the vacuum gage
      Alternative versions of schemes of recovery repair of the engine
      Removal of the power unit from the car - preparation and precautionary measures
      Removal and installation of the engine
      Order of dismantling of the engine by preparation it to capital repairs
      Dismantling of a head of cylinders
      Cleaning and check of a condition of a head of cylinders
      Service of valves
      Assembly of a head of cylinders
      Removal of conrod and piston assemblies
      Removal of a bent shaft
      Cleaning of the block of the engine
      Check of a condition of the block
      Honingovaniye of mirrors of cylinders
      Check of a condition of components of conrod and piston group
      Check of a condition of a bent shaft
      Check of a state and selection of inserts of radical and conrod bearings of a bent shaft
      Check of a condition of camshafts, pushers of valves and bearings
      Engine assembly order
      Installation of piston rings
      Installation of a bent shaft and check of working gaps of radical bearings
      Installation of a back epiploon of a bent shaft
      Installation of conrod and piston assemblies and check of size of working gaps in conrod bearings of a bent shaft
      Trial start and running in of the engine after capital repairs
+ Cooling systems, heating
+ Power supply system and release
+ Engine electric equipment
+ Control systems of the engine
+ Transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment

Check of a condition of camshafts, pushers of valves and bearings

 PERFORMANCE ORDER

1. Check bearing surfaces under installation of camshafts for existence of cavities, scratches, zadir and other signs of excessive wear. In case of detection of defects it is necessary to replace a head.

2. Measure the outer diameter of each of bearing necks of shaft. Write down results of measurements and compare them to the nominal rates specified in Specifications. Measure internal diameters of bearings in heads of cylinders and subtract from results of the last measurements results corresponding the first. The received difference will make the size of gaps in bearings of shaft. Compare the obtained data with requirements of Specifications. In case of need make replacement of shaft and/or heads.

3. Estimate the size of a radial beating of shaft, stacking them in V-shaped blocks and using the dial measuring instrument of plunger type. Rotate a shaft in blocks slowly, write down the taken readings and compare them in nominal rates (see Specifications). In case of need replace the corresponding shaft.

4. By means of a micrometer measure height of cams of shaft. Compare results of measurements to requirements of Specifications, then subtract them from the last for the purpose of definition of degree of wear of cams. If wear exceeds extreme admissible value (see Specifications), replace the corresponding shaft.

5. Estimate a condition of working surfaces of pushers of valves.

If the contact surface of a pusher is worn-out, it makes sense to estimate also a condition of a working ledge of the corresponding cam of a distributive shaft / an adjusting washer on DOHC engines.

On SOHC engines pushers should be held vertically in order to avoid hit of air in them (see the Part SOHC Engines of the present Chapter).

6. By means of a micrometer measure the outer diameter of each pusher. Compare results of measurements to requirements of Specifications. Replace the pushers which are worn out over an admissible limit.

7. Measure diameter of each pusher, compare results of measurements to requirements of Specifications. In case of need replace assembly of guides (SOHC engines), or a head of cylinders (DOHC engines).

8. Subtract sizes of outer diameters of pushers from sizes of internal diameters of the corresponding nests in a guide/head for the purpose of definition of a gap of landing of pushers in nests, - at installation of new components (pushers, a guide/head) the probability of an exit of this parameter out of limits of admissible values is not excluded.
9. On SOHC engines estimate degree of wear of yokes and their axes (see the Part SOHC Engines of the present Chapter). At excessive wear of overlays of a yoke are subject to replacement - at all do not make attempts of carrying out their recovery wear.
10. Remember that the condition of all components, - new or suitable for the further use old before installation has to be without fail checked.