Maximum allowable wear of main mating engine parts
The wear parts are paired mainly with replaceable parts, which allows you to repair the cylinder block by regrinding or replacing liners, replacing worn camshaft bushings with semi-finished ones and then processing them to the required size, replacing crankshaft main bearing shells.
Restoring the performance of a pair of cylinder block bore - pusher due to their slight wear comes down to replacing the pushers.
Repair and replacement of cylinder liners
Fig. 1. Puller for pressing out the liner from the cylinder block: 1 - puller; 2 - sleeve; 3 - cylinder block
The maximum allowable wear of cylinder liners should be considered as an increase in the gap between the sleeve and the piston skirt up to 0.3 mm.
If there is such wear, press the liner out of the cylinder block using a puller 1 (Fig. 1) and bore it to the nearest piston repair size with a machining tolerance of +0.06 mm.
Do not clamp the sleeve into the jaw chuck during processing, as this will deform the sleeve and distort its dimensions.
Fix the sleeve in the device, which is a sleeve with seat belts with a diameter of 100 and 108 mm.
Insert the sleeve into the bushing until it stops against the upper collar, which is clamped with the overlay ring in the axial direction.
After processing, the liner cylinder mirror should have the following deviations:
1. Ovality and taper not more than 0.01 mm, and the larger base of the cone should be located in the lower part of the sleeve.
2. Barrel and corset - no more than 0.08 mm.
3. The beating of the cylinder mirror relative to the landing belts with a diameter of 100 and 108 mm is not more than 0.01 mm.
Fig. 2. Measurement of the protrusion of the sleeve above the plane of the block
After pressing the liner into the cylinder block, check the protrusion of the upper end of the liner above the upper plane of the block (Fig. 2).
Protrusion should be 0.005-0.055 mm. If the protrusion is insufficient (less than 0.005 mm), the head gasket may be pierced; in addition, coolant will inevitably enter the combustion chamber due to insufficient sealing of the upper belt of the liner with the cylinder block.
When checking the protrusion of the end of the sleeve above the block, it is necessary to remove the rubber sealing ring from the sleeve.
Fig. 3. Clamp for sleeves: 1 - nut; 2 - washer; 3 - sleeve
To prevent the liners from falling out of their sockets in the block during repairs, secure them with washers 2 and bushings 3, put on the cylinder head mounting studs, as shown in fig. 3.
Cylinder liners bored out to the third oversize of the piston, after wear, replace with new ones.
Related parts |
Ultimately admissible, mm |
Place and method of measurement |
|
gaps |
ellipse and taper |
||
Cylinder - piston |
0,3 |
─ |
Measure the cylinder in two mutually perpendicular directions (along the axis of the crankshaft and perpendicular to it) and two belts (at a distance of 8-10 mm and 60-65 mm) from the top of the block. Take the largest size. Measure the piston at a distance of 5-10 mm from the bottom of the skirt in the plane, perpendicular to the axis of the piston pin |
Main and connecting rod journals crankshaft - liners |
0,15 |
─ |
Measure as indicated in the article |
Crankshaft journal |
─ |
0,07 |
Along the axis of the crankshaft and perpendicular to it |
Crankshaft journal |
─ |
0,05 |
Too |
Axial clearance of the crankshaft |
0,25 |
─ |
Measure with a probe in several places around the circumference |
Camshaft axial clearance |
0,25 |
─ |
Too |
Axial clearance of connecting rod |
0,5 |
─ |
Too |
Cylinder block - pusher |
0.1 |
─ |
Measure in two belts on the length of the working surface |
Valve - guide sleeve |
0.25 |
─ |
Too |
Camshaft journal - sleeve |
0.15 |
─ |
— |
Camshaft journal |
─ |
0.05 |
─ |
Piston pin - bushing top connecting rod heads |
0,10 |
─ |
Measure in two belts on the length of the working surface |
Piston pin - piston |
0,10 |
─ |
Too |
Connecting rod bushing |
─ |
0,02 |
Measure along the axis of the connecting rod and perpendicular to it |
piston pin |
─ |
0,01 |
Too |
Piston ring - groove in piston (height) |
0,15 |
— |
Measure with a probe in several points around the circle |
Piston ring - gap in the lock |
3,0 |
— |
— |
Table: Dimensional groups of pistons
Designation dimensional groups |
Limit deviations skirt diameter, mm |
А |
0,000 -0,012 |
Б |
+0,012 0,000 |
В |
+0,024 +0,012 |
Г |
+0,036 +0,024 |
Д |
+0,048 +0,036 |