Inspection
1. Check the condition of the connecting rod and main journals of the crankshaft so that there is no wear or scratches, check them for ovality and taper. If the dimensions of the working surface do not fall within the allowable limits given in the Specifications at the beginning of this Section, the connecting rod and / or main journals will need to be reground.
2. When the bottom end of the connecting rod and the crankpin are worn, metallic detonation is felt, especially noticeable when the engine is loaded at low speeds, all this is accompanied by some drop in oil pressure.
3. When the main bearing and main journal are worn, a strong vibration of the engine is felt - increasing with increasing speed, and again accompanied by a drop in oil pressure.
4. If the crankshaft needs to be reground, contact an engine repair specialist, he will also tell you the correct repair dimensions of the liners.
5. Inspect the connecting rod end and main bearings for signs of general wear, wear, pitting, and scratches. Bearings should be matte grey. Bearings with indium content in the substrate, and if the protrusion of copper-colored inclusions on the working surface is noticeable, the bearings are considered to be heavily worn. Replace bearings if they are in this condition or if there are other signs of wear or pitting. We strongly advise you to replace the liners, regardless of their condition, during the overhaul of the engine. Installing used bearings is a false economy.
6. Oversized repair bushings are designed to fit into a re-ground crankshaft. In fact, the liners are slightly larger than stated, as there are working tolerances in their manufacture.
7. Main and connecting rod bearings can be identified by markings on the end. Standard sized earbuds are marked with STD or.00, oversized earbuds are marked with the stated outer dimension of 0.020 u/s. This marking method only applies to replacement liners, not to those used in engine production.
8. A special Plastigage tool is used to accurately determine bearing wear. The crankshaft is located in the main bearings (and, if necessary, connecting rod), and a piece of Plastigage is placed across the neck. Opel recommends liberally lubricating the crankshaft journals and bearings to prevent the Plastigage from sticking and tearing when the bearing cap is removed. The cover is installed and the bolts are clamped with the tightening force regulated by the Specifications. The cover is then removed and the width of the crushed Plastigage is measured using a special table which shows the operating clearance of the bearing. The clearance must be compared with the data in the Specifications.
9. Where applicable, check that the teeth on the crankshaft TDC sensor wheel are not damaged (see illustration). If these damages are found, the crankshaft must be replaced.
10. Similarly, check the condition of the pins in the front crankshaft counterweights that are used to install the diagnostic sensor unit used by Opel dealers (see illustration).
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