Assembling Flywheels

After correct connecting rod bearing fit has been attained, clean and assemble parts as follows: Install sprocket shaft to left flywheel and pinion shaft and crank pin to right flywheel. Check to make sure oil passages through pinion shaft, right flywheel and crank pin are clear by blowing compressed air into hole near end of pinion shaft.

Position right flywheel assembly in vise, crank pin up. Wipe crank pin taper clean. Slip bearings and connecting rods over crank pin with forked rod to

4. Left flywheel

5. Connecting rods (one forked, one single end)

6. Bearing rollers and retainers

7. Lock plate screw (see item 1)

Figure following name

10. Right flywheel

11. Pinion shaft

12. Pinion shaft key

13. Lock plate screw (see item 1)

14. Lock plate (see item 2)

15. Crank pin lock nut (see item 3)

16. Crank pin part indicates quantity necessary fi

17. Crank pin key

18. Lock plate screw (see item 1)

19. Lock plate (see item 8)

20. Sprocket shaft nut (see item 9)

21. Sprocket shaft

22. Sprocket shaft key

23. Flywheel washer (2)

24. Flywheel washer (see item 23)

one complete assembly.

Figure 3E-8. Flywheel Assembly - Exploded View rear cylinder. Wipe crank pin hole in left flywheel clean and dry. Install left flywheel and tighten nut lightly. Hold steel straightedge along outer face of wheel rims at 90 degrees from crank pin as shown in Fig. 3E-10. Tap outer rim of top wheel until wheels are concentric. Tighten nut. Recheck with straightedge 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. Adjust so centers are snug. 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, 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-I1 or a combination of two of the three ways.

When wheels are both out of true as indicated in "A," tighten a C-clamp on rims of wheels opposite crank pin and lightly tap the rim at the crank pin with lead or copper mallet.

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

Figure 3E-12. Truing Flywheels on Truing Stand

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 (see Fig. 3E-12).

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. This could result in a broken crank pin.

Readjust centers, revolve wheels and take reading from indicator. Repeat truing operation until indicated run out does not exceed .001 in. (each graduation on indicator is .002 in.).

If it is impossible to true wheels, check 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 using Crank Pin and Flywheel Nut Wrench, Part No. 94545-26, or use torque wrench and tighten to foot-pound reading given in "Engine Specifications." Check connecting rod side play with thickness gauge as shown in Fig. 3E-13. If it is greater than tolerance shown in "Engine Specifications," Section 3A, draw up crank pin nuts until within tolerance. Insufficient play between rods and flywheel face is caused by one of the following conditions:

1. Flywheels and crank pin assembled with oil or tapers and nuts over-tightened. Disassemble, clean, reassemble.

2. New flywheel washers installed and not fully seated. Disassemble, inspect, replace deepest seating flywheel or exchange crank pin. As last resort, grind down width of forked rod.

3. Taper holes enlarged as a result of having been taken apart several times. Replace wheel seating deepest.

4. Cracked flywheel at tapered hole. Replace flywheel.

If sides of forked rod are ground to get desired clearance, backs of bearing retainers must be ground down to remain narrower than width of female rod.

After rod sideplay is checked and adjusted, crank pin nut pulled very tight and lock plate and screw installed, again recheck wheel trueness on truing device. Correct any run-out as above.

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