Crankshaft

Cleaning

 CAUTION: Handle the crankshaft (6303) with care to avoid possible damage to the finished surfaces.

Clean the crankshaft with solvent, then blow out all oil passages with compressed air.

Inspection

Measure the diameter of each journal in at least four places to determine an out-of-round, taper or undersize condition. For specifications, refer to Section 03-01A (4.9L SFI), Section 03-01B (5.0L and 5.8L MFI), Section 03-01C (7.5L MFI) or Section 03-01D (7.3L diesel).

On an engine (6007) with a manual transmission (7003), check the fit of the pilot bearing in the bore of the crankshaft. A needle roller bearing and adapter assembly is used as a pilot bearing. It is press fit directly into the engine crankshaft and should not be loose. Inspect the inner surface of the pilot bearing for wear or a bell-mouth condition. Check the inside diameter of the pilot bearing to see if it is worn or damaged. The bearing and adapter assembly cannot be serviced separately. The pilot bearing can only be installed with the seal end of the bearing facing the transmission. The bearing and seal are pregreased and do not require additional lubrication.

NOTE: A new bearing must be installed whenever a bearing is removed.

Inspect the pilot bearing, when used, for roughness, evidence of overheating or loss of lubricant. Replace if any of these conditions are found.

Crankshaft Runout

1. NOTE: Check crankshaft journals for out-of-round before checking for runout, or an out-of-round condition on the center journal could be confused for an excess runout condition.

   Set V-blocks on surface plate and set crankshaft on V-blocks supported on the outer two main bearing journals.

2. Set up Dial Indicator with Bracketry TOOL-4201-C or equivalent to measure runout on center main bearing journal.

3. Zero dial indicator.

4. Slowly rotate crankshaft one revolution, recording highest and lowest readings.

5. Crankshaft runout should not exceed 0.03mm (0.0012 in.). If crankshaft runout is excessive, replace crankshaft.

   

Crankshaft End Play

Refer to crankshaft end play elsewhere in this section. Crankshaft must be installed in block with the bearings that will be used, but without connecting rods (6200), pistons, or flywheel (6375) installed to check end play.

Journals, Refinishing

Dress minor imperfections such as scores, nicks or burrs with an oil stone.

If journals are severely marred or exceed service limits for wear, taper, or out of round, they should be refinished to size for the next undersize crankshaft main bearing.

Follow crankshaft lathe manufacturer's instructions for refinishing crankshaft.

If the journals will not clean up to less than the maximum undersize bearing available, replace the crankshaft.

Always reproduce the same journal shoulder radius that existed originally. Too small a radius will result in fatigue failure of the crankshaft. Too large a radius will result in bearing failure due to radius ride of the crankshaft bearing.

After refinishing the journals, chamfer the oil holes. Polish the journals with a No. 500 grit polishing cloth and engine oil (crocus cloth may also be used as a polishing agent) to obtain a smooth finish.

Crankshaft Sprocket

Inspect crankshaft sprocket or gear for chipped, broken, or excessively worn teeth. If necessary, remove and replace as outlined in Section 03-01A (4.9L SFI), Section 03-01B (5.0L and 5.8L MFI), Section 03-01C (7.5L MFI) or Section 03-01D (7.3L diesel).