Truing And Sizing Connecting Rod Lower Race

up to same size, rather than fit with rollers of two sizes.

When rods are correctly fitted with required bearing clearance, extreme upper end of female (forked end) rod will have just noticeable side shake; extreme upper end of male (single end) rod will have .025" to 1/32" side shake. This check should be made with bearings clean and free of oil. Fitting tighter is likely to result in a seized and damaged bearing shortly after engine is put back in service.

Overall width of roller retainer assembly must be less than width of female rod end. Check to be sure of this.

Assembling Connecting Rods and Flywheels

After correct connecting rod bearing fit has been attained, thoroughly clean all parts and lubricate with engine oil preparatory to assembling flywheels. Install connecting rods on crank pin bearing so female (forked end) rod will be to rear and male (single end) rod will be to front.

With right side flywheel and rod assembly held in vise copper jaws, wipe crank pin taper and left flywheel taper perfectly clean and free of oil, then install left flywheel and align as nearly as possible concentric with right wheel by means of a straight edge held against outer face of wheel rims, 90° from crank pin—see Illus. 51. Install nut on crank pin and tighten lightly. Check rim faces again with straight edge and, if tightening nut has shifted wheel, correct its position by striking rim of wheel with a lead or copper hammer. Do not use steel hammer. Turn nut tighter and repeat straight edge check. To prevent flywheel assembly from toning in vise while tightening nut, insert a rod approximately W diameter and at least 5" long through holes in flywheels and shift flywheels in vise jaws so that rod bears against some part of vise.

Determining Correct Lower Bearing Fit

(See "Checking Connecting Rod Lower Bearing for Excessive Wear and Looseness," for infor mation on checking lower bearing in connection with top overhaul and how much looseness may be allowed before bearing must be refitted.)

After lapping lower races of used rods as necessary, to smooth and true them, or replacing rods with a set with new lower races, install set of rollers and retainers on crank pin; rollers must always be new. Check fit of rods on bearing assembly. In making this check, flywheel pinion gear shaft must be gripped tightly between copper-faced vise jaws to hold flywheel firmly in a horizontal position. If neither rod will start over bearing, select a smaller set of rollers. If they go over easily and there is considerable shake at top end of rods, install a larger set of rollers. If lower end race of one rod is found to be slightly larger than the other, select rollers of a size that come closest to correctly fitting larger rod race and then lap rod with smaller race to bring it

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