Jeep Engines - Oljeep

286 MOPAR PERFORMANCE PARTSCRANKSHAFTThe 4.2L crankshaft has twelve counterweights; thecrankshaft is counterweighted and balanced independently.It has seven main bearings and six connecting rod journals.The crankshaft has a main bearing journal diameter of63.489-63.502 mm (2.4996-2.500 1 'I), and main bearingjournal widths of (No. I) 27.58-27.89 mm (1.086-1.098"),(No. 2) 32.28-32.33 mm (1.271-1.273"), and (Nos. 3, 4, 5,6 and 7) 30.02-30.18 mm (1.182- 1.188").The crankshaft has a connecting rod journal diameter of53.17-53.23 mm (2.0934-2.0955") and a connecting rodjournal width of 27.18-27.33 mm (I ,070- 1.076").The component parts of the crankshaft assembly areindividually balanced; then the complete assembly isbalanced as a unit.Note: On automatic transmission equipped engines, thetorque converter and converter flexplate must be markedprior to removal and installed in this position uponassembly.Service replacement dampers, crankshafts, flywheels,torque converters and clutch components are balancedindividually and, therefore, may be replaced as requiredwithout rebalancing the complete assembly.If the crankshaft is damaged to the extent thatreconditioning is not feasible, it must be replaced. Theengine must be removed from the vehicle for crankshaftreplacement.For more crankshaft specifications, refer to 4.2L EngineSpecificutions, 'Engine Assembly' section of this chapter.CRANKSHAFT MAIN BEARINGSThe main bearings are steel backed, sintered copper, leadalloy precision type.Each bearing is selectively fit to its respective journal toobtain the desired operating clearance. In production, theselect fit is obtained by using various-sized, color-codedbearing inserts.When required, different sized upper and lower bearinginserts may be used as a pair; therefore, a standard sizeupper insert is sometimes used in combination with a .001"undersize lower insert.Service replacement bearing inserts are available as pairs inthe following undersizes: standard, .001",.002",.010", and,012". The size is stamped on the back of the inserts.It may be necessary, in some instances, to use differentsized upper and lower inserts to reduce clearance by .0005".C ran ks haf tThe bearing insert nearest to standard should always beinstalled in the upper location.Caution: Never use bearing inserts with greater than .001"difference in size in pairs.Upper - Std.Lower - .OO 1 'I undersizeRemovalUpper - S td..Lower - .002" undersizeI. Disconnect the battery negative cable.2. Remove the spark plugs.3. Raise the vehicle.4. Remove the oil pan and oil pump. Refer to Oil PumpRemoval and Oil Pun Removal, 'Oiling System'section of this chapter, for the procedures.5. Remove the main bearing caps and lower inserts.6. Remove the lower insert from the bearing cap.7. Remove the upper insert by loosening (DO NOTremove) all of the other bearing caps and inserting asmall cotter pin tool in the crankshaft journal oil hole.Bend the cotter pin as illustrated to fabricate the tool(Figure 2-13). With the cotter pin tool in place, rotatethe crankshaft so that the upper bearing insert willrotate in the direction of its locking tab.Note: Because there is no hole in the No. 3 mainjournal, use a tongue depressor or similar soft-facedtool to remove the bearing insert. After moving theinsert approximately 25 mm (l"), it can be removed byapplying pressure under the tab.8. Using the same procedure just described, remove theremaining bearing inserts (one at a time) forinspection.