Crankshaft

Fig. 35 Main Bearing Cap Tightening Sequence:

1. Before installing crankshaft, inspect main bearing oil clearance as follows:
a. Remove any foreign material and oil from journals and bearings.
b. Install upper main bearings and thrust bearings. Main bearings with oil grooves are installed into cylinder block and oil groove of the thrust bearing faces the crankshaft.
c. Set crankshaft into cylinder block and position Plastigage on top of journals in axial direction.
d. Install main bearing caps along with lower main bearings according to cap numbers and arrows.
e. Tighten caps in two or three steps in proper sequence, Fig. 35. Torque to 14 ft. lbs. and tighten additional 90°, then an additional 45°. Do not rotate crankshaft when measuring oil clearances.
f. Remove main bearing caps and measure Plastigage at each journal at widest point for smallest clearance, and at the narrowest point for the largest clearance.
g. If oil clearance exceeds .0031 inch (.08mm), grind crankshaft and use undersize main bearings.
2. Apply a liberal amount of engine oil to main bearings, thrust bearings and main journals.
3. Install crankshaft and main bearing caps according to cap number and arrow.
4. Tighten main bearing caps, noting the following:
a. Measure bolt length, which should be 3.35 inches (85mm). If length exceeds 3.37 inches (85.5mm), replace bolt.
b. Apply engine oil to threads and the seat face of the bolt.
c. Torque bolts in sequence, Fig. 35, to 14 ft. lbs.
d. Place paint mark on each bolt head.
e. Using paint mark as reference, tighten bolts, in sequence, an additional 90°.
f. Tighten bolts, in sequence, an additional 45°.
5. Inspect crankshaft endplay, which should be .0031-.0111 inch (.08-.282mm).
6. If endplay exceeds .0118 inch (.30mm), grind crankshaft and install oversize thrust bearing or replace crankshaft and thrust bearing. oversize thrust bearings are available in widths of 0.0787-0.0807 inch (2.000-2.050mm), .0837-.0856 inch (2.125-2.175mm) and .0886-.0906 inch (2.25-2.3mm).