Removal
1. Remove the power unit from the engine compartment (see the relevant chapter).
2. Disconnect the gearbox from the engine.
3. Remove the timing cover.
4. Remove the cylinder head (see the relevant chapter).
5. Remove the crankshaft rear oil seal cover.
6. Unscrew the mounting bolts and remove the connecting rod bearing caps.
Attention! Bearing caps 1-5 are marked with corresponding numbers on the exhaust valve side (see arrows in the illustration). Covers 6 and 7 are not numbered.
7. Loosen the tightening of the main bearing cap bolts, acting in the sequence 1-7, unscrew the bolts and stow so that when reassembling to install the caps in their original places 9 See illustration). If available, use a fixture KM-849.
(The article was published on the website OpelBook.ru)
8. Remove the main bearing caps and place them in a sequence that ensures their subsequent installation in their previous mounting locations. If available, the KM-849 device can be used to place the caps.
Caution! Do not place the removed crankshaft on the oil pump gear.
9. Remove the crankshaft from the cylinder block.
10. Clean and inspect all parts for damage and wear and replace them if necessary.
Caution! If you are replacing the crankshaft, remove the oil pump gear from the old one and secure it to the new shaft by tightening the mounting bolts to 5.5 Nm.
Installation
11. Lubricate the main bearing shells with engine oil and place them in the cylinder block.
12. Install the main bearing caps and secure them with new bolts. When installing the caps, make sure that the grooves on them match the lower grooves for the engine oil outlet (see arrows in the illustration).
13. Tighten the main bearing cap bolts to 25 Nm and then turn them an additional 50°, following the sequence 7-1 (see illustration 7.12).
14. Install the connecting rod bearings.
15. Install the crankshaft rear oil seal cover, replacing the old sealing gasket with a new one.
16. Install the timing cover.
17. Connect the gearbox to the engine and install the power unit in the engine compartment.
Crankshaft - checks
Clearance between the liners and journals of the main bearings of the crankshaft. Measurement using a calibrated plastic wire - method "Plastigage"
The clearance between the liners and the journals of the crankshaft main bearings is checked by calculation, measuring the parts. Before this, the crankshaft and its journals are cleaned, and the liners are lubricated with a thin layer of motor oil.
18. Usually, a calibrated plastic wire is used to check the gap.
19. Clean the working surface of the liners and the corresponding neck and place a piece of plastic wire on its surface (see arrow in illustration).
20. Install the main bearing cap on the journal being checked and tighten the mounting bolts to 25 Nm, then turn them an additional 50°.
21. Unscrew the bolts and remove the bearing cover, then use the scale on the plastic wire package to determine the gap size by flattening the wire (see illustration). The permissible gap between the liners and covers is 0.020-0.058 mm.
Measuring the clearance of connecting rod bearings using a bore gauge
In this case, the clearance between the connecting rod bearing liners is determined by measuring the bearing diameter with a bore gauge at three points. The results obtained are summed up and divided by 3. The result is the average diameter value (see illustration 7.21a).
Example:
I - the result obtained when measuring at point I - 57.972 mm
II - the result obtained when measuring at point II - 57.981 mm
III - the result obtained when measuring at point III - 57.984 mm
173.937:3 = 57.979 mm
22. Measure the diameter of the corresponding crankpin at two points using a micrometer, add up the obtained values and divide them by 2.
Example:
I - the result obtained when measuring at point I - 57.962 mm
II - the result obtained when measuring at point II - 57.964 mm
115.926: 2 = 57.963 mm
To obtain the value of the clearance of the connecting rod bearing shells, the value of the journal diameter should be subtracted from the value of the bearing diameter:
57.979 mm - 57.963 mm = 0.016 mm
The permissible gap is 0.016-0.058 mm.
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