Note. To perform the procedures below, you will need a micrometer and a plunger-type dial gauge.
Removing
1. Remove the engine from the vehicle, then remove the cylinder head, oil pan, oil pump intake, timing belt cover, timing and timing chains, and flywheel/drive plate from the engine.
2. Give fixing bolts and, having carefully prying, remove the holder of a back epiploon of a cranked shaft from the block of cylinders and a pin of a shaft.
3. Make sure that there are identification marks on the connecting rods and caps of their lower heads (apply them yourself if necessary).
4. Give fixing nuts and remove covers of the lower heads of rods, folding them in order of placement on the engine. Raise the connecting rods slightly by removing their lower heads from the shaft journals, but without pushing the pistons out of the cylinders.
5. Inserting the feeler blades between the crank web and the sixth main bearing, check the crankshaft end play. Push the shaft all the way into the leading edge of the center main bearing, then push the shaft all the way forward to determine end play.
Note. Alternatively, the end play of the shaft can be determined using a digital plunger-type meter mounted against the end of the shaft stud (see accompanying illustration).
6. If the axial play exceeds the allowable value (see tables of sizes and adjustments at the end of the guide), replace the center main bearing assembly.
7. Using the Plastigage measuring set, check the clearances in the main bearings of the crankshaft:
- Remove the first bearing cap and thoroughly wipe the shaft journal and bearing shell with a clean, lint-free cloth.
- Lay a piece of calibrated plastic wire from the measuring set (length equal to the width of the bearing) along the neck of the shaft.
- Install the bearing cover and tighten its fastening bolts to the required torque.
Note. Do not rotate the shaft with the measuring wire laid on its neck.
- Give bolts and carefully remove a cover with the bottom loose leaf of the bearing.
- Using the scale printed on the Plastigage package, measure the width of the flattened gauge wire to determine the bearing clearance.
- The widest section of the flattened wire corresponds to the minimum gap, and vice versa.
- Similarly, check the clearances in the remaining bearings.
8. Carefully remove the crankshaft from the crankcase, making sure that the upper main bearing shells do not fall out or are damaged (if they are reused).
9. If the liners are to be replaced, remove the old ones from your beds in the block.
10. Establish in the holder a new back epiploon of a cranked shaft.
Status check
1. Check the crankshaft main and connecting rod journals for signs of wear, taper and ovality. If the degree of wear exceeds the permissible values (see tables of sizes and adjustments at the end of the guide) relevant (main or connecting rod) necks should be machined to the nearest of the standard repair sizes, choosing the appropriate size (with humiliation) liners. Remember that even in case of wear or defect of only one of the necks, all the necks in the set are subject to turning (main or connecting rod respectively).
2. If the degree of wear is such that turning the journals does not help to correct the situation, the crankshaft must be replaced.
3. Check the thrust surfaces of the central main bearing for cavities and actuation marks. If necessary, replace the thrust bearing shells, which should bring the crankshaft axial play in line with the regulations (see tables of sizes and adjustments at the end of the guide).
4. Even if the clearances in the main bearings are found to be satisfactory, check their liners for scratches, scoring, flaking, cavities and wear marks. If necessary, replace defective liners in pairs with new ones of the appropriate size.
Installation
Installation is in the reverse order.
1. Monitor the reliability of the patency of all oil flows and do not forget to thoroughly wipe all necks (main and connecting rod) with a clean, lint-free cloth.
2. Thoroughly wipe all new or old bearings, then lubricate them with clean engine oil. Track correctness of installation of loose leaves in the corresponding beds of the block, covers or heads of rods.
3. Lay the crankshaft in the cylinder block, guiding the connecting rod journals into the heads of the respective connecting rods.
4. Place the bearing caps on the respective connecting rods and block bearings, tighten the mounting bolts / nuts to the required torque (see tables of sizes and adjustments at the end of the guide).
5. If the bearing shells have been replaced, check the clearances in them using the Plastigage measuring set.
6. Install the rear oil seal holder, timing and drive chains, flywheel/drive plate and other removed components.