Crankshaft
REMOVALProcedures after removing crankshaft sprocket oil pan, pistons and connecting rods.
1. Using Tool MB995022, remove front crankshaft oil seal. Be careful not to damage the seal surface of cover.
2. Pry out rear seal with screwdriver. Be careful not to nick or damage crankshaft flange seal surface or retainer bore.
3. Remove main bearing cap bedplate.
4. Remove bearing lower.
5. Remove crankshaft.
6. Remove bearing upper.
7. Remove knock sensor.
8. Remove oil pressure switch.
9. Remove oil level gauge (dipstick).
INSTALLATION
1. Install oil level gauge (dipstick).
2. Install oil pressure switch.
3. Install knock sensor. Tighten knock sensor to 10 Nm (7 ft. lbs.) torque. Over or under tightening effects knock sensor performance, possibly causing improper spark control.
4. Select proper thickness main bearing shells.
NOTE: Upper and lower No. 3 bearing halves are flanged to carry the crankshaft thrust loads and are NOT interchangeable with any other bearing halves in the engine.
Bearing shells are available in standard and the following undersized: 0.016 mm, 0.032 mm, 0.250 mm.
Never install an undersized bearing that will reduce clearance below specifications.
5. Install the main bearing shells with the lubrication groove in the cylinder block.
NOTE: All upper bearing shells in the crankcase have oil grooves. All lower bearing shells installed in the (bedplate) main bearing caps are plain. Crankshaft end play is controlled by a flanged bearing on the number three main bearing journal.
6. Make certain oil holes in block line up with oil hole in bearings and bearing tabs seat in the block tab slots.
7. Oil the bearings and journals and install crankshaft.
CAUTION: Do not get oil on bedplate mating surface. If may effect the sealer ability to seal the bedplate to cylinder block.
8. Apply 1.5 to 2.0 mm (0.059 to 0.078 inch) bead of Loctite 19614 to cylinder block as shown in the figure.
9. Install main bearing cap bedplate together with lower bearing shells.
CAUTION: Use only the specified anaerobic sealer on the bedplate or damage may occur to the engine.
10. Before installing the bolts, the threads should be oiled with engine oil.
11. Install main bearing bedplate to engine block bolts (1 thru 10) finger tight, then torque main bearing bolts to 75 Nm (55 ft. lbs.) in sequence shown in the figure.
12. Install main bearing bedplate to engine block bolts (A thru K) finger tight, then torque each bolt to 28 Nm (20 ft. lbs.) in sequence shown in the figure.
13. Place new front seal into opening with seal spring towards the inside of engine. Install seal by using Tool MB995022 until flush with oil pump cover.
CAUTION: If burr or scratch is present on the crankshaft edge (chamfer), cleanup with 400 grit sand paper to prevent seal damage during installation of new seal.
NOTE: When installing seal, no lube on seal is needed.
14. Place Special Tool MB99505g on crankshaft. This is a pilot tool with a magnetic base.
15. Position seal over pilot tool. Make sure you can read the words THIS SIDE OUT on seal. Pilot tool should remain on crankshaft during installation of seal.
16. Drive the seal into the block using Special Tool MB995060 and handle C-4171 until the tool bottoms out against the block.
CAUTION: If the seal is driven into the block past flush, this may cause an oil leak.
INSPECTION
Crankshaft Main Journals
1. The crankshaft journals should be checked for excessive wear, taper and scoring. Limits of taper or out-of-round on any crankshaft journals should be held to 0.025 mm. (0.001 inch). Journal grinding should not exceed 0.305 mm (0.012 inch) under the standard journal diameter. Do NOT grind thrust faces of Number 3 main journal. Do NOT nick crank pin or journal fillets. After grinding, remove rough edges from crankshaft oil holes and clean out all passages.
CAUTION: With the nodular cast iron crankshafts used it is important that the final paper or cloth polish after any journal regrind be in the same direction as normal rotation in the engine.
Crankshaft Bearing Clearance
1. The total clearance of the main bearings can only be determined by removing the weight of the crankshaft. This is accomplished by having the engine turned upside down on the engine stand. This will remove all the crankshaft weight off the bearing surface.
2. Place a piece of Plastigage across the entire width of the bearing shell in the bedplate approximately 6.35 mm (0.25 inch) off center and away from the oil holes. In addition, suspect areas can be checked by placing the Plastigage in the suspect area. Torque the bedplate bolts of the bearing being checked to the proper specifications.
CAUTION: Do not rotate crankshaft, or the Plastigage may be smeared.
3. Remove the bedplate and compare the width of the flattened Plastigage with the metric scale provided on the package.
Standard value: 0.022 - 0.062 mm (0.0009 - 0.0024 inch)
Main Bearing Bolts
1. Since the main bearing bolts are torqued using a new procedure, they should be examined BEFORE reuse If the threads are necked down, replace the bolts.
2. Necking can be checked by holding a scale or straight edge against the threads. If all the threads do not contact the scale, the bolt should be replaced.
Checking Crankshaft End Play
1. Mount a dial indicator to front of engine, locating probe on nose of crankshaft.
2. Move crankshaft all the way to the rear of its travel using a lever inserted between a main bearing cap and a crankshaft cheek, using care not to damage any bearing surface. Do not loosen main bearing cap.
3. Zero the dial indicator.
4. Move crankshaft all the way to the front and read the dial indicator.
Standard value: 0.09 - 0.24 mm (0.0035 - 0.0094 inch)
Limit: 0.37 mm (0.015 inch)
5. Replace No. 3 main bearing if limit is exceeded and remeasure.
6. Replace crankshaft if limit is still exceeded.
Optional Crankshaft End Play Check
1. Move crankshaft all the way to the rear of its travel using a lever inserted between a main bearing cap and a crankshaft cheek, using care not to damage any bearing surface. Do not loosen main bearing cap.
2. Use a feeler gauge between number three thrust bearing and machined crankshaft surface to determine end play.