Assembling Flywheels

After correct connecting rod bearing fit has been attained, clean all parts and lubricate bearings with engine oil. Install connecting rods on crank pin bear ing so female rod is to rear cylinder. Assemble key and sprocket shaft to left flywheel with sprocket shaft nut, lock plate and lock plate screw.

Position right flywheel assembly in vise. Wipe crank pin taper and crank pin hole in left flywheel clean and dry. Install left flywheel and tighten nut lightly. Hold steel straight edge along outer face of wheel rim at 90 degrees from crank pin as shown in Fig. 3E-24. Tap outer rim of top wheel until rim faces of both wheels are in alignment. Tighten nut. Recheck with straight edge at frequent intervals. Use soft metal hammer to realign wheels. To prevent flywheel assembly from turning in vise while tightening nut, insert a rod 5 in. long and about 1/2 in. in diameter through holes in flywheels and between vise jaws so that rod bears against some part of the vise.

When nut is fairly tight, install flywheel assembly in Flywheel Truing Device, Part No. 96650-30 as shown in Fig. 3E-25. Adjust so centers are just snug.

Figure 3E-23. Lapping Connecting Rod Bearing Race

Wheels must turn freely but shafts may not be loose in centers. If flywheel assembly is either loose or squeezed, indicators will not indicate accurately. Adjust indicators to take reading as near to flywheels as possible, and so pointers read at about the middle of the scales.

Turn flywheels slowly and observe the movement of indicator pointers. Movement toward flywheels indicate high points of shafts. Find highest point of each shaft and chalk-mark flywheel rims at those points. Loosen centers slightly, just enough so looseness may be detected, and make corrections as follows:

Flywheels may be out of true three ways, A, B and C, Fig. 3E-26, or a combination of two of the three ways.

When wheels are both out of true as indicated in "A," a C-clamp is tightened on rims of wheels opposite

Figure 3E-25. Truing Flywheel on Truing Stand crank pin and the rim at the crank pin is moderately tapped with lead or copper mallet.

When wheels are both out of true as indicated in "B," a hardwood wedge is driven between the wheels opposite the crank pin and the rims near the crank pins moderately tapped with a mallet.

When wheels are out of true as indicated in "C," strike the rim of the wheel a firm blow at about 90 degrees from crank pin on high side.

When wheels are out of true in a combination of any of conditions shown, correct A or B first, tapping rim of offending wheel only, and then correct condition C.

The number of blows required and how hard they should be struck depends on how far shafts are out of true and how tight nuts are drawn. Remember that centers must be loosened slightly before striking flywheels. Making them too loose may result in damaged centers. Never strike wheels a hard blow near crank pin.

Re-adjust centers, revolve wheels and take reading from indicator. Repeat truing operation until indicators show run-out to be no more than .001 in. (each graduation on indicator is .002 in.).

If it is impossible to true wheels, look for a cracked flywheel, damaged or enlarged tapered hole, or a sprocket or pinion shaft worn out of round at surface where indicator reading is being taken.

When wheels are true, position in vise and draw crank pin nuts very tight. Check connecting rod side-play with thickness gauge as shown in Fig. 3E-27. If it is greater than tolerance shown in "Engine Specifi-

Figure 3E-24. Squaring Flywheel Faces
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