CRANKSHAFT AND MAIN BEARINGS-H.3 7. Check that the crankshaft end T;oat is within the limits given on Page B.6 by means of feeler gauges as shown in Fig. H.7. If incorrect, oversize thrust washers are available to give an overall reduction of 0.015 in (0,38 mm) (Refer to Page H.1 ). 8. Refit the rear main oil seal half housing. NOTE: If any leakage of oil is apparent from this seal then new seals should be fitted to the half housing as described under the heading "Crank- shaft Rear End Oil Seal" or fit a new assembly 9. Refit the suction pipe assembly and sump. To Remove the Crankshaft To remove the crankshaft it will be necessary to re- move the engine from the vehicle or application. 1.
Remove the starter motor, flywheel and flywheel housing. (Refer to Page P.1 for details of flywheel and flywheel housing removal) 2. Remove the crankshaft front pulley. timing case cover, timing gears and fuel pump drive hub. (Refer to Page J.1 for details of their removal) 3. Remove the timing case back plate. 4. Remove the sump and lubricating oil pump com- plete with suction and delivery pipes. (Refer to Page L.1 for removal of these). 5. Remove all the connecting rod setscrews. con- necting rod caps and bearing shells. (Refer to Page F.1). NOTE: All the bearing shells should be marked to indicate "top" or "bottom" and number of the rod assembly. 6. Unscrew the main bearing cap setscrews.
H7 Crankshaft Regrinding The crankshafts fitted to most 4.108 and some 4.107 engines are Tufftrided and these crankshafts must be re-hardened after regrinding. If facilities are not avail- able for Tufftriding, the crankshaft can be re-hardened by the 20 hour nitriding process but if this cannot be carried out, then a replacement crankshaft should be fitted. The Tufftrided crankshafts can be recognised by the part number that is stamped on the crankshaft nose or No. 1 web. The part numbers of the Tufftrrded crankshafts are 31315741, 31315827, 31315828, 31315829, 31315831. 31315836, 31315838. 31316111 31316112. 31316113. 31316114. 31316122. 31316128and 31316121.
The crankshafts fitted to 4.99 and most 4.107 and some 4.108 engines are induction hardened and do not require re-hardening after regrinding. The crankpin and main journal diameters can be re- ground to 0.010 in (0.25 mm), 0.020 in (0,51 mm) or 0.030 in (0,76 mm) undersize. For crankshaft regrind data, see Page H.5. When regrinding, only very light cuts should be used and adequate cooling must be maintained, especially around the fillet radii. The crankshaft should be crack detected and de-magnetised before and after regrinding and the fillet radii and the surface finish must be main- tained to within the limits given on Page B.6.
After regrinding and before polishing and where necessary, rehardening, the oil holes should be chamfered 0.0201 0.060 in (0,51/1,52 mm) at 45 to blend smoothly into the crankpin and main Journal diameters. NOTE: The rear seal half housing securing set- screws will require removal to enable the rear main bearing cap to be removed. (Refer to Fig. H.3) 7. Lift out the crankshaft and place where it is not likely to be damaged ready for inspection. 8. Remove the top half main bearing shells. 9. Finally, remove the top half oil seal housing. To Refit the Crankshaft 1. First ensure that crankshaft oilways are clear. 2.
Place the three top bearing shells in position then oil liberally with clean engine oil. NOTE: Unless a new set of main bearings is being fitted, those removed must be returned to their original locations. H6