- By means of a special vertical drill completely remove traces of step wear from the top part of cylinders - act according to the instructions of the manufacturer attached to a vertical drill. The step is formed on piston stroke border, approximately in 6.4 mm under the top cut of the cylinder due to mechanical production of metal and a nagaroobrazovaniye, it is possible to determine its existence to the touch by a finger nail. Attempts of extraction of conrod and piston assemblies without removal of step development are fraught with damage of pistons.
Removal of step wear from the upper edge of the cylinder by means of a special vertical drill
- Having finished preparation of cylinders, turn the engine upside down so that the bent shaft appeared from above.
- Before removing rods from a bent shaft, estimate the size of an axial side play of their landing on the corresponding necks of the last. Densely enter an edge(s) of the measuring probe into a gap between a sidewall of the lower head of a rod and a cheek of a crank, having completely chosen a rod side play on a shaft neck. Total thickness of the picked-up probe edges will also equal to the size of an axial side play of a rod. Compare result of the taken measurement to requirements of Specifications. If the size of an axial side play exceeds extreme admissible value, this rod is subject to replacement. The axial side play of a new rod, or old on new to a shaft, can appear less than the lower admissible limit, in this case the rod can be pierced, - consult with specialists of car service. Serially check all remained rods.
Measurement of size of an axial side play of conrod and piston assemblies
- Make sure available on the lower heads of rods and their covers of identification tags of belonging to the cylinder, in case of need put tags independently by means of a small center punch or a marker.
Before removal make sure available on covers of rods of identification marking, in case of need put it independently by means of a marker or a small center punch
- Turn a bent shaft so that pistons of the 1st and 4th cylinders appeared in provisions of NMT.
- In stages (on 1/2 turns for approach) weaken nuts/bolts of fastening of a cover of the lower head of a rod of the first cylinder so that the possibility of their otvorachivaniye manually appeared. Uncover a rod together with the bearing insert placed in it, - try not to drop the last.
On some engines the section of the lower head of rods is formed by a preparation razlamyvaniye with preservation of a form of a break by special processing for the best quality of a joint. At dismantle of covers from rods of this kind observe extreme care, - do not damage the interfaced surfaces.
- For protection of a neck of a shaft and a mirror of the cylinder pull couple of pieces of the hose suitable by the size on hairpins of fastening of the lower head of a rod.
- Take a bearing insert from a rod head, then, having rested the wooden handle of the hammer against a bearing bed in the lower head, push out conrod and piston assembly from the block at the top of the cylinder. At emergence of resistance immediately stop extraction of assembly and make sure of completeness of removal of step wear in the top part of the cylinder.
- Working in a similar manner, take conrod and piston assembly of the 4th cylinder from the engine, then turn the engine on the 180th hail. clockwise also take assemblies of the 2nd and 3rd cylinders.
Start extraction only after the rod is located strictly parallel to a cylinder axis!
- In order to avoid casual mechanical damage of bearings and loss of components, establish into place inserts and fix covers of bearings on the lower heads of the rods, having by hand tightened fixing bolts / nuts.
- Do not remove pistons from rods.