Crankshaft: Service and Repair

CRANK SHAFT





COMPONENT

DISASSEMBLY
1. Remove the timing belt, front case, flywheel cylinder head assembly and oil pan.
2. Remove the rear plate and the rear oil seal.
3. Remove the connecting rod caps.

NOTE: Mark the main bearing caps to permit reassembly in the original position and direction.

4. Remove the main bearing caps and remove the crank shaft. Keep the bearings in order by cap number.

INSPECTION
1. Check crankshaft bearing and crank pin journals for damage and scoring.
2. Check oil holes for clogging.
3. Set crankshaft on V-blocks.





4. Measure crankshaft run-out at center journal. Replace crankshaft if it is not within specification.
5. Grind crankshaft only if there is visible scoring, or if out-of-round is excessive.
6. Only grind crankshaft amount necessary to correct condition.
7. If a crankshaft must be ground 0.020 inch (0.50 mm) or more, heat-treat crankshaft to ensure durability.





MAIN JOURNAL DIAMETER UNDERSIZES:





CRANK PIN JOURNAL DIAMETER UNDERSIZES:

MAIN BEARING AND CONNECTING ROD BEARINGS





1. Check main and connecting rod bearings for peeling, scoring and other damage.

MAIN BEARING SELECTION











1. Standard main bearing selection





2. Main bearing housing bore size





3. Main journal shaft diameter





4. Main bearing thickness

REASSEMBLY
1. Inspect journals and bearings for any foreign material. Clean crankshaft, oil holes, and main bearing journals thoroughly, and dry components with compressed air.
2. Install grooved main bearings into saddles on engine block.





3. Install thrust bearings with oil groove facing crank shaft.
4. Set crankshaft on installed bearings.
5. Install remaining main bearings into main bearing caps.
6. Position Plastigauge on crankshaft journals.
7. Install main bearing caps along with lower main bearings according to cap number and <- mark.





8. Tighten main bearing cap bolts.

CAUTION: Do not rotate crankshaft with Plastigauge on crankshaft journals.





9. Remove main bearing caps and check bearing clearance.

NOTE: The widest point of Plastigauge is the smallest clearance, and the narrowest point of Plastigauge is the largest clearance.





10. If oil clearance exceeds specification, grind and polish crankshaft and use undersized main bearings.
11. Lift crankshaft out of cylinder block and carefully remove Plastigauge from main bearings and crankshaft journals.
12. Apply a light coat of engine oil on main bearings and install crankshaft by gently lowering it onto bearings.
13. Apply a light coat of oil on crankshaft main bearing journals and on main bearings on main bearing caps.
14. Install main bearing caps along with lower main bearings according to cap number and <- mark.





15. Tighten main bearing cap bolts according to the following procedure:
Tighten bolts in order shown
16. Rotate crankshaft to ensure it does not bind.
17. Place a dial indicator against front of crankshaft and zero gauge.
18. Using a prying tool, move crankshaft forward and zero dial indicator.





19. Move the crankshaft toward the rear of block with prying tool and check the amount of movement on dial indicator.
20. If end play exceeds specification, grind crankshaft and install oversized thrust bearings, or replace crankshaft and thrust bearings.





OVERSIZE THRUST BEARING WIDTH

21. Install the oil seal in the crankshaft rear oil seal case. Press fit the oil seal all the way in, being careful not misalign it.
22. Install the rear plate and tighten the bolts.
23. Install the connecting rod caps. Refer to "Piston and Connecting Rods".
24. Install the flywheel, front case, oil pan and timing belt.