1. Position the crankcase so that the pistons are pointing up. On flange mounted air compressors it may be advisable to place the crankcase in a soft-jawed vise.
2. Lubricate the cylinder block bores, pistons, and piston rings with lubricating oil.
3. Place a new gasket on the crankcase.
4. Rotate the crankshaft so that the piston and connecting rod assemblies are at the top center and bottom center, respectively.
5. Recheck the ring position gaps.
6. On cylinder blocks having an inlet mounting pad surface, rotate the cylinder block with respect to the crankshaft to ensure proper location of the air cleaner assembly.
7. Place the cylinder block over the pistons. Slowly bring the cylinder block down onto the pistons until the cylinder block is flush to the crankcase.
NOTE: A slight downward pressure will be required to move the cylinder block down as it will be squeezing the piston rings when they slide into their respective bores.
8. If the governor bracket was mounted to the cylinder block before disassembly, replace the governor bracket in its original position.
9. Assemble the six cap screws or nuts, and lock washers. Torque the two center bolts from 7 to 9 N·m (60 to 80 lb in); then the four end bolts. Increase the bolt torque from 13 to 18 N·m (120 to 160 lb ft) tightening the two center bolts and then the four end bolts.