Cylinder block — cleaning and inspection (Opel Omega B2)

Cleaning

1. Remove all external components and electrical switches/sensors from the block. For complete cleaning, the plugs must be removed. On 4-cylinder engines, the plugs are pressed in; To remove the plug, drill a small hole, then screw a self-tapping screw into it and use pliers or a sliding hammer to remove the plug. On 6-cylinder engines, the plugs are threaded.

2. Clean the cylinder block from any remaining gasket or sealant, being careful not to damage the surfaces.

3. Remove all oil channel plugs (where are there). They are usually very tight and will probably need to be drilled out. Use new plugs when reassembling the engine. On 6-cylinder engines, it is also recommended to remove the oil bypass valve; The valve is located behind the oil filter (when installing, use a new one)To remove the bypass valve, cut a thread in the center of the valve using an M10 tap. Screw a bolt with a washer and a socket into the hole as a spacer (see illustrations).







4. If any part of the crankcase is heavily contaminated, steam cleaning will be required.



5. Clean all lubrication holes and channels one more time. Rinse all channels with warm water. Dry all contact surfaces thoroughly and apply a thin layer of oil to prevent corrosion. Also lubricate the cylinder walls with oil. To speed up the drying process and blow out all lubrication holes and channels, it is recommended to use compressed air (see illustration).



6. If the crankcase is not very dirty, cleaning can be done with hot soapy water and a stiff brush. Regardless of the cleaning method, carefully monitor the cleanliness of all oil holes and passages, and thoroughly dry all components. Protect the cylinder walls as described above to prevent corrosion.

7. All tapped holes must be clean and dry to ensure accurate tightening torques during assembly. Run a suitable tap along each hole thread to clean and restore any rust, deposits or sealant. When finished, blow compressed air through the holes again to remove any dirt particles that may have appeared during this process. Also clean the threads of the cylinder head bolts and the main bearing cap bolts.

Text copied from an online resource: OPELBOOK.ru



8. Apply a suitable sealant to the new oil passage plugs and insert them into the holes in the block and tighten securely.

9. If the engine is not going to be assembled right away, cover it with a large plastic bag; protect all contact surfaces and cylinder walls as described above to prevent corrosion from developing.

Inspection

10. Inspect the crankcase parts for cracks and corrosion. Check the integrity of the threads in the holes. If there are signs of internal coolant leakage, have a specialist diagnose the block using special equipment. If defects are found, repair (if possible) or replace the unit.

11. Check the cylinder bores for nicks and notches.

12. Measure the diameter of each cylinder at the top (just below the wear step), in the central and lower part of the cylinder, parallel to the crankshaft axis. Please note that there are different size groups of nominal diameter, taking into account permissible manufacturing deviations; the size group marking is printed on the top side of the cylinder block.

13. Compare the results with the Specifications at the beginning of this Section. If any measurement exceeds the Specification limit, the cylinder block must be rebored if possible or replaced and new piston assemblies installed.

14. If the cylinder walls are heavily worn, or in case of excessive ovality, taper, or if the clearance between the piston and the cylinder wall is exceeded (see Chapter 12), the cylinder block must be bored (if possible), or replace and install new pistons. Repair pistons (0.5 mm) are available for all engines.



15. If the cylinders are in good condition and not worn to the limits specified in the Specifications, then the piston rings should be replaced. In this case, the cylinders must be honed so that the new rings are properly seated. This increases the bearing surface of the piston rings, and accordingly improves the seal between the piston and the cylinder. The honing tool is driven by an electric drill. In addition, some kerosene will be required (or honing oil) and rags. Lubricate the cylinder bores with honing oil, insert the tool into the bore, squeezing the stones. Turn on the drill and move it up and down in the bore. Ideally, the honing lines should intersect at an angle of 60°, although some piston ring manufacturers may specify a different angle. Use oil when honing. Do not remove more material than necessary. When finished, do not remove the tool from the bore while it is rotating; slide it down until the nozzle stops, then remove the tool by rotating it by hand in the normal direction. If new pistons are being installed, manufacturers may specify different honing angles, so refer to the ring manufacturer's instructions first. After honing, wipe off all honing oil. If you do not have the necessary tools or skills, contact an engine repair specialist.

16. On 6-cylinder engines, drive the new oil bypass valve completely into the cylinder block using a hammer and pipe punch (a 15mm socket would be ideal) (see illustrations).