Section 03-00: Engine, Service | 1996 All F-150, F-250, F-350, F-Super Duty and Bronco Vehicles Equipped with 4.9L, 5.0L, 5.8L or 7.5L Gasoline Engines, and 7.3L Diesel Engines Workshop Manual |
Plastigage® Method
Clean crankshaft journals. Inspect journals and thrust faces for nicks, burrs or roughness that would cause premature bearing wear. When replacing standard bearings with new bearings, it is good practice to fit bearing to minimum specified clearance. If desired clearance cannot be obtained with a standard bearing, try a 0.050mm (0.002-inch) undersize bearing set to obtain proper clearance.
CAUTION: Do not position jack under crankshaft pulley. Crankshaft post damage will result.
If fitting main bearing in-vehicle, position a jack under counterweight adjoining bearing which is being checked. Support crankshaft (6303) with jack so its weight will not compress Plastigage® D81L-6002-B or equivalent and provide an erroneous reading.
Place a piece of Plastigage® D81L-6002-B or equivalent on bearing surface across full width of bearing cup and about 6.35mm (1/4 inch) off center.
| Item | Part Number | Description |
|---|---|---|
| 1 | D81L-6002-B | Plastigage® |
| 2 | — | Plastigage® Scale (Part of D81L-6002-B) |
| A | — | Check Width of Plastigage® |
| B | — | Location of Plastigage® Prior to Tightening |
Install cap and tighten bolts to specification. Do not turn crankshaft while Plastigage® is in place.
Remove cap. Using Plastigage® scale, check width of Plastigage® at widest point to get minimum clearance. Check at narrowest point to get maximum clearance. Difference between reading is taper of journals.
If bearing clearance exceeds the specified limits, try using one of the various combinations of undersize bearings as directed by the accompanying table. Use of any other bearing combination is not recommended. Bearing clearance must be within specified limits. Refer to Specifications 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), for main and connecting rod bearing clearance limits. If use of these bearing combinations does not bring clearance to the desired limits, refinish the crank journal to a standard undersize, and use the appropriate undersize bearing.
After bearing has been fitted and cleaned, apply a light coat of engine oil to journal and bearings. Install bearing cap. Tighten cap bolts to specification.
Repeat procedure for remaining bearings that require replacement.
Refer to Crankshaft End Play procedure in this section for proper thrust bearing seating.
| For This Amount Of Bearing Clearance Excess | Use This Bearing Size (Upper Bearing) | Use This Bearing Size (Lower Bearing) | |||
|---|---|---|---|---|---|
| mm | Inch | mm | Inch | mm | Inch |
| 0.0-0.013 | 0.0-0.0005 | 0.025 | 0.001 U.S. | Standard | Standard |
| 0.013-0.026 | 0.0005-0.0010 | 0.025 | 0.001 U.S. | 0.025 | 0.001 U.S. |
| 0.026-0.039 | 0.0010-0.0015 | 0.050 | 0.002 U.S. | 0.025 | 0.001 U.S. |
| 0.039-0.052 | 0.0015-0.0020 | 0.050 | 0.002 U.S. | 0.050 | 0.002 U.S. |
Bore Gauge Method
Install bearings in the cylinder block (6010) and bearing caps.
Install crankshaft and tighten main bearing cap bolts to the specified torque as outlined in the appropriate 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).
Remove bearing caps and crankshaft.
Reinstall bearing caps with bearings still installed in cylinder block and caps.
Tighten bearing cap bolts to torque specified in appropriate 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).
Using micrometer, measure main bearing journals.
Using bore gauge, measure the inside diameter of each bearing assembly. It may be necessary to measure the outer bearings first, then remove those caps and measure the inner bearings.
Subtract the maximum measurement for each journal from the minimum measurement of each bearing to determine the minimum oil clearance.
Allowable clearances are as follows: