Crankshaft: Service and Repair

CRANKSHAFT, FLYWHEEL AND DRIVE PLATE





DISASSEMBLY AND REASSEMBLY

INSPECTION

CRANKSHAFT
(1) Check the crankshaft journals and pins for streaks and seizure. Replace if necessary.








(2) Measure the journal O.D. and main bearing I.D. to obtain the clearance between the two (oil clearance). If the clearance exceeds the limit, replace the main bearing and, if necessary, the crankshaft.

Standard value: 0.02-0.05 mm (.0008-.0020 in.)

Limit: 0.1 mm (.0040 in.)

CAUTION A special surface treatment has been applied to crankshaft. Do not machine it to undersize.

CRANKSHAFT OIL CLEARANCE (PLASTIC GAUGE METHOD)
The crankshaft oil clearance can be measured easily by using a plastic gauge, as follows:
(1) Remove oil and grease and any other foreign matters from crankshaft journal and bearing inner surface.
(2) Install the crankshaft.





(3) Cut the plastic gauge to the same length as the width of bearing and place it on journal in parallel with its axis.
(4) Gently place the crankshaft bearing cap over it and tighten the bolts to the specified torque.
(5) Remove the bolts and gently remove the crankshaft bearing cap.





(6) Measure the width of the smashed plastic gauge at its widest section by using a scale printed on the plastic gauge bag.

CRANKSHAFT REAR OIL SEAL
(1) Check oil seal lip for wear and damage.
(2) Check rubber for deterioration or hardening.
(3) Check oil seal case for cracks and damage.





RING GEAR
Check teeth of ring gear for wear and damage. If necessary, replace the ring gear.
If the ring gear teeth are worn or damaged, also check the starter motor pinion.
To remove the ring gear, strike the ring gear at several points on its outer circumference. The ring gear cannot be removed if it is heated.
To install the ring gear, heat the ring gear to 300°C (572°F) for shrink fit.





FLYWHEEL
(1) Check the clutch disc friction surface for ridge wear, streaks, and seizure. If necessary, replace flywheel.
(2) If the runout of flvwheel exceeds the limit, replace.

Limit: 0.13 mm (.0051 in.)

DRIVE PLATE
Replace deformed, damaged, or cracked drive plates.

SERVICE POINTS OF REASSEMBLY

14. INSTALLATION OF CRANKSHAFT BEARING (UPPER)
Install the upper crankshaft bearing to the cylinder block.
There is an oil groove in the upper crankshaft bearing.
There is no difference between upper and lower bearings for the center (with flange).

12. INSTALLATION OF CRANKSHAFT BEARING (LOWER)
Install the lower crankshaft bearing (with no oil groove; there is no difference for center) to each bearing cap and apply engine oil to bearing surfaces.





11. INSTALLATION OF BEARING CAP
(1) Verify the correct identification mark and the direction of the arrow for installation.





(2) After installing the bearing caps, make sure that the crankshaft turns smoothly and the end play is correct. If the end play exceeds the limit, replace crankshaft bearings.

Standard value: 0.05-0.18 mm (.0020-.0071 in.)

Limit: 0.25 mm (.0098 in.)





10. INSTALLATION OF OIL SEAL
Using the special tool, press-fit the oil seal into the crankshaft rear oil case. Use a new oil seal.





9. INSTALLATION OF OIL SEPARATOR
Force the oil separator into the oil seal case so that the oil hole in the separator is directed downward (arrow in illustration).