LO 8-11 Identify and describe the purpose, function, and types of diesel engine flywheels

SKILL DRILL 8-1  Reinstalling a Flywheel Housing

STEP 1
Clean the flywheel housing and inspect it for damage caused by a previously loose transmission mounting.

STEP 2
Mount a dial indicator on the face of the flywheel or crankshaft.

STEP 3
Place the indicator pointer on the inside circumference of the housing.

STEP 4
Mark the flywheel housing at 12 o’clock, 3 o’clock, 6 o’clock, and 9 o’clock.

STEP 5
Zero the dial indicator at 12 o’clock. Turn the engine through 90 degrees of crankshaft rotation. After stopping the crankshaft rotation, measure how far the dial indicator moved at each of the reference points and whether it moved in or out.

STEP 6
Record the dial indicator movement in four places.

STEP 7
Identify the Society of Automotive Engineers (SAE) size of the flywheel housing that the engine uses by measuring its opening diameter.

STEP 8
After identifying the SAE flywheel size, determine the maximum permissible runout for the flywheel housing size. Larger housings are allowed more runout than smaller housings.

STEP 9
Compare the total indicated runout (TIR) measured on the flywheel with the specifications in the provided table. TIR is calculated by subtracting the maximum movement at each position from its opposite minimum measure. For example, if the dial indicator moved 0.010" (0.254 mm) out at 3 o’clock and −0.004" (−0.102 mm) at the 9 o’clock position, the TIR is 0.006" (0.152 mm).

STEP 10
If the TIR is more than the allowed specification, the housing needs to be moved. To move a housing a small amount (less than 0.020" [.508 mm]), loosen all but two bolts in the housing. Tap the housing with a heavy hammer (a 5–10 lb [2–5 kg] sledge) in the correct direction to compensate for the off-center position. Recheck the bell housing runout once again to determine whether it is within specifications. On a housing that requires significant movement, remove the alignment dowels to move the housing. After the housing is aligned, redrill the dowel holes and reinstall the dowels.

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