Removal
Note: before removing parts of the connecting rod and piston group, it is necessary to dismantle the cylinder head and pan (see chapter 2A).
1. Using your fingernail, check for presence in the cylinder (about 6 mm from the top) ridge, which may be in the upper position of the piston ring. If the presence of ridges formed as a result of wear on the cylinder surfaces and the accumulation of carbon deposits is confirmed, completely remove the defects using a special tool (see illustration). Follow the instructions for using the tool. Attempting to remove connecting rod piston parts without first removing existing ridges may result in damage to the pistons.
9.1. Remove the ridge that is located at the top of the cylinders using a special reamer - this must be done before removing the pistons
2. Once the ridges have been removed, turn the cylinder block upside down to expose the crankshaft.
3. Before removing the main bearing caps and connecting rods, check the end play of the connecting rods using a feeler gauge set. Insert feeler gauges between the end surface of the lower head of the first connecting rod and the crankshaft cheek until a feeler gauge is selected that slides in this gap with slight resistance (see illustration). Perform the described operation on each connecting rod. The axial play will correspond to the thickness of the feeler gauge. Check with your auto repair shop for the permissible limit for axial play (as a rule, it lies in the range of 0.13 - 0.38 mm). If the axial play exceeds the limit, it is necessary to replace the connecting rods. When installing new connecting rods (crankshaft) The end play may be less than the specified limit. In this case, it is necessary to machine the connecting rods. If necessary, consult a workshop.
9.3. Check the connecting rod end play using a feeler gauge set
Motor bearing condition analysis
Pollution
Incorrect assembly
Reboot
Inconsistency of provisions
Lack of lubrication
Corrosion
Lack of lubrication
4. Make sure there are identification marks on the connecting rods and bearing caps. If the marks are missing or difficult to see, apply them using a felt-tip pen or paint, marking each connecting rod and cover (e.g. 1, 2, 3, etc., depending on the cylinder number).
Caution: Do not use a punch or hammer to mark the connecting rods as this method may damage them.
5. Alternately loosen the connecting rod cap bolts by half a turn at a time until you can unscrew them by hand.
Note: During subsequent assembly, be sure to install new connecting rod bearing cap bolts. Do not throw away the old bolts immediately after removing them, as they should be used when checking the oil clearance of the connecting rod bearings.
6. Remove the cover and bearing shell of the first connecting rod. Do not allow the liner to fall out of the cover.
7. Remove the bearing shell and push the connecting rod/piston through the top of the cylinder. Push the connecting rod by resting the handle of a wooden or plastic hammer on the working surface of the bearing. If resistance is felt during ejection, ensure that the ridge at the top of the cylinder is completely removed.
8. Carry out the described procedure on the remaining cylinders.
9. After removing the connecting rod-piston group, reassemble the bearing caps and shells with the corresponding connecting rods, tightening the cap bolts by hand. Leave the old bearings in the connecting rods to prevent damage to the working surfaces before starting the assembly procedure.
10. Thus, the pistons/connecting rods are ready for inspection and restoration in a workshop.
Installing piston rings
11. Before installing the piston rings on the pistons, measure the cut gaps. It is assumed that the side clearances of the rings have been previously checked.
12. Arrange the pistons/connecting rods and rings in a certain order, which will ensure that the rings can be installed on those pistons and in those cylinders where the clearances were measured.
13. Enter the top (first) ring into the first cylinder and, pushing the piston, position it perpendicular to the cylinder walls (see illustration). Move the ring to the base of the cylinder, to a position that corresponds to the bottom dead center of the piston.
9.13. When measuring the gap, the ring should be positioned perpendicular to the cylinder walls (this is achieved by pushing the ring into the cylinder with a piston, as shown in this illustration)
14. To determine the ring cut gap, insert feeler gauges into the cut until you select a feeler gauge whose width is equal to the gap size (see illustration). Such a probe should slide through the cut with little resistance. The compression ring gap should be between 0.25 - 0.50 mm, and the oil ring gap should not exceed 0.76 mm. If the obtained and given values do not correspond, make sure once again that the rings are selected correctly. Contact the auto shop where you purchased the rings to confirm that they are the correct type.
9.14. With the ring positioned perpendicular to the cylinder walls, measure the gap using a set of feeler gauges
15. If the ring gap is too small, it must be adjusted to normal, otherwise the ends may close during engine operation, which will lead to serious damage to the power unit. If necessary, increase the gap by carefully filing the ends of the ring with a fine-grit file. Secure the file in a vice with soft pads, position the ring so that the file is in the gap and, slowly moving the ring, widen the gap to the required value. File by moving the ring only in the direction of the vice, from the outer end of the file (see illustration).
9.15. If the gap is too small. it should be brought back to normal. Place the file in a vice and file the ends of the piston ring
16. If the ring gap exceeds the norm by only 1 mm, then such a deviation should not be considered critical. Again, make sure you select the correct rings.
17. Carry out the described procedure with the remaining rings of the first cylinder and with each ring in the remaining cylinders. Remember to match the rings, cylinders and pistons.
18. After checking and adjusting the clearances, you can begin installing the rings on the pistons.
19. As a rule, the oil scraper ring is installed first (in the down position on the piston), which consists of three parts. Install the expander/seal into the groove (see illustration). If a locating pin is provided, make sure it fits into the hole in the piston ring groove. Then, using the same method, install the upper component of the ring (see illustration). Do not install the oil scraper ring components using a special tool as this may damage the parts. Instead, place one end of the ring component in the groove between the seal and the base of the groove and press firmly, wrapping your finger around the piston and guiding the ring component into the groove. Then install the bottom component in the same way.
9.19a. Install the expander/seal into the groove
9.19b. Do not install oil scraper ring components using a special tool
20. After installing the oil scraper ring, make sure that the upper and lower parts can be rotated freely in the groove.
21. Then install the second (average) compression ring. As a rule, there is a mark on it that should face up. Do not confuse the top and middle compression rings as they have different cross-sections.
Note: Follow the instructions provided with your new piston ring sets. The principles for installing rings from different manufacturers may differ.
22. Make sure that the mark is located on the top side of the ring, then install the ring into the middle groove on the piston using the special tool (see illustration). Do not spread the ring more than necessary to fit it into the piston groove.
9.22. Set the second and first (top) ring using a special device. Make sure the ring marks are facing up
23. Install the upper compression ring in the same way. Make sure the ring mark is positioned correctly. Do not confuse the first and second compression ring.
24. Follow the above procedures with the remaining pistons and rings.
Installation
25. Before installing pistons/connecting rods, make sure the cylinder walls are absolutely clean. The procedure is carried out after preliminary installation of the crankshaft and rounding of the upper edges of the cylinders by grinding.
26. Remove the cover of the first connecting rod (pay attention to the marks made during removal). Remove the old earbuds and wipe with a clean cloth (lint-free) the working surface of the bearing on the connecting rod and its cover. Work surfaces should be kept immaculately clean.
Checking the oil clearance of connecting rod bearings
27. Clean the back of the new upper bearing shell, then install it into the connecting rod.
28. Make sure that the protrusion of the liner and the notch of the connecting rod are aligned. Do not seat the bearing shell with a hammer, and do not damage the bearing shell's working surface. At this stage, the liner is not lubricated during installation.
29. Clean the back of the other bearing shell and install it into the connecting rod cap. Make sure that the protrusion of the liner and the recess of the cover are aligned. At this stage, the liner is not lubricated during installation. It is extremely important to ensure that the mating surfaces of the bearing, connecting rod and cap are spotlessly clean after assembly.
30. Arrange the piston ring cuts in the order shown (see illustration).
9.30. Location of ring cuts
31. Lubricate the piston and rings with assembly oil. Install a ring compressor onto the piston. The piston must protrude about 6 mm from the fixture so that it can be guided into the cylinder. The rings should be compressed until their surface is level with the surface of the piston skirt.
32. Rotate the crankshaft, bringing the first connecting rod journal to the position corresponding to the bottom dead center of the piston (BDC), then apply a layer of engine oil to the cylinder wall.
33. Place the mark on the piston towards the front of the engine (towards the chain), carefully insert the piston and connecting rod assembly into the first cylinder and press the lower edge of the ring compressor against the cylinder block.
34. Tap the top edge of the device that compresses the rings to make sure that it fits tightly to the block along the entire circumference of the cylinder.
35. Gently tap the piston bottom with the wooden handle of a hammer (see illustration), seating the connecting rod on the crankshaft journal. The piston rings may pop out of the ring compressor just before entering the cylinder, so it should be lightly pressed against the block. Carry out the procedure in a measured rhythm, and if resistance to the movement of the piston in the cylinder occurs, stop immediately. Be sure to determine the cause of the jam before continuing. Never force the piston into the cylinder using excessive force, as this may cause the piston and/or its rings to break.
9.35. The piston can be inserted into the cylinder by gently tapping it with a wooden hammer handle
36. After installing the piston/rod assembly, the connecting rod bearing oil clearances should be checked before final installation of the connecting rod caps.
37. Cut strips of plastic indicator of suitable size (slightly shorter than the width of the connecting rod bearing shell) and place it on the first crankpin, parallel to the shaft axis (see illustration).
9.37. Place indicator strips on the crankpins parallel to the crankshaft axis
38. Clean the mating surface with the liner in the cover. Make sure the alignment marks of the cap and connecting rod are aligned (see illustration 9.4).
39. Tighten the old cover bolts to the required torque.
Note: During the connecting rod bolt tightening procedure, a thin-wall socket socket should be used to avoid high torque errors that may occur due to the socket being wedged between the bolt and the connecting rod cap. If the head jams, you should lift it slightly and remove it from the gap between the bolt and the cover. Do not rotate the crankshaft during this procedure.
40. Unscrew the bolts and carefully remove the connecting rod cover. Do not allow the plastic indicator section to move. The cover bolts can now be discarded as new fasteners are required to be installed during final assembly.
Note: You MUST install new connecting rod cap bolts.
41. Compare the width of the crushed section of the indicator with the scale diagram that comes with the indicator, and determine the size of the oil gap (see illustration). The gap should be 0.025 - 0.05 mm. Check the value by consulting the company station.
9.41. Compare the width of the crushed section of the indicator with the scale diagram and determine the size of the oil gap (To determine the gap, compare the widest part); make sure that the gap was determined according to the appropriate diagram - the indicator is equipped with an inch and metric scale
42.If the gap is outside the required value, a mismatch in the size of the liners should be assumed (which means they need to be replaced). Before deciding to replace the bearings, make sure that there was no dirt or grease layer between the surfaces of the covers, connecting rods and bearings when measuring the gap. Also measure the diameter of the crankshaft crankpin. If the indicator expands at one of its ends, then the corresponding crankpin may be tapered. If the clearance still exceeds the required value, install bearings of reduced size.
Caution: When installing a new crankshaft, always install standard size connecting rod bearings.
Final installation
43. Carefully remove any remaining plastic indicator from the surfaces of the crankpins and/or bearing shells. Clean off any traces of indicator with your fingernail or the edge of a plastic card, being careful not to damage the bearing surfaces.
44. Make sure that the working surfaces of the bearings are impeccably clean, then lubricate both bearings on each side with molybdenum or assembly oil. To gain access to the connecting rod bearing surface, the piston must be advanced in the cylinder.
Caution: Install new bolts into the connecting rod caps. The use of old fasteners is unacceptable because they are stretched.
45. Place the connecting rod on the journal, install the cover and tighten the new bolts to the required torque. As before, tightening in this case is carried out in three stages.
46. Follow the procedures described for the remaining pistons/rods.
47. Some important features should be noted:
- A) Before assembly, make sure the back surfaces of the liners, connecting rods and caps are absolutely clean.
- b) Make sure the cylinders, pistons and connecting rods match.
- With) The mark located on the piston should face forward.
- d) Lubricate the cylinder walls with clean engine oil.
- e) Lubricate the bearing surfaces when installing the connecting rod caps, after checking the oil clearances.
48. After installing the pistons/rods, rotate the crankshaft by hand to ensure that it rotates smoothly and smoothly.
49. Finally, check the connecting rod end play again.
50. Make sure that the axial play complies with the standard by comparing the obtained values with the values given in the specifications. If before disassembly the axial play corresponded to the norm, and during assembly the same connecting rods and crankshaft were installed, then the axial play should be within the same acceptable limits. If a new crankshaft and connecting rods are installed, the axial play of the connecting rods may not meet the standard. If the play is not within the normal range, the connecting rods should be removed and taken to a workshop for machining.