TM 9-2815-237-34 2-44          Change 1 2-16.   CYLINDER BLOCK REPAIR (Cont‘d) d.  Repair 1. Boring. a.   Before using any type of boring bar, the top of the cylinder block should be filed off to remove any dirt or burrs.  This is very important.  If not checked, the boring bar may be tilted, which would result in the rebored cylinder wall not being at right angles to the crankshaft. b.    Measure piston diameter of the piston to be used at the skirt across the center line of the piston pin. c.    Using a boring bar, bore the cylinder to the same diameter as the piston.  Hone the cylinder to get proper piston-to-bore clearance. d.   Repeat steps b. and c. for remaining cylinders. 2. Honing. a.    Using cylinder bore gauge, measure cylinder bore (2) for cylinder bore diameter. Measurement must be taken at point “A” (4) 2-1/2 in. (64 mm) from top of cylinder bore (2). b.    Measure “piston diameter” of piston (5) removed from corresponding cylinder using a micro- meter at piston skirt (7) across center line of piston pin (6). c.    Subtract “piston diameter” from “cylinder bore diameter” to determine “piston-to-bore clearance”. d.   Repeat steps a. through c. for remaining cylinder bores and pistons. NOTE • Cylinders can be conditioned with a hone or boring bar and fitted with a standard “Hi-Limit” piston or oversized piston, if necessary. • If a cylinder is pitted or worn such that it cannot be honed and fitted with a “Hi-Limit” piston or oversized piston, a cylinder sleeve may be used to repair the engine block. • 6.5L engines do not have “Hi-Limit” pistons. e.    If all cylinder bores (2) have proper “piston-to-bore clearance” of 0.004-0.005 in. (0.102-0.127 mm) or if proper “piston-to-bore clearance” may be obtained using a standard “Hi-Limit” piston or oversized piston, go to step f. If not, engine may be repaired using a cylinder sleeve (para. 2-16.d.2). NOTE If cylinder bores are found to have less than 0.005 in. (0.127 mm) wear, taper, or out-of-round, they may be honed oversize (refer to para. 2-16.d.1) and fitted with “Hi-Limit” standard size pistons. 8. Using cylinder bore gauge, measure all cylinder bores (2) for taper. Measurements must be taken at point “A” (4) at top and bottom of cylinder bore (2). If any cylinder exceeds specifications (table 2-2 or 2-3) by 0.005 in. (0.127 mm) or more, repair cylinder or replace engine. 9. Using cylinder bore gauge, measure all cylinder bores (2) for out-of-round. Measurement must be taken at point “A” (4) and point “B” (3) at top and bottom of cylinder bore (2). If any cylinder exceeds specifications (table 2-2 or 2-3) by 0.005 in. (0.127 mm) or more, repair cylinder or replace engine. 10. Using cylinder bore gauge, measure all cylinder bores (2) for bore diameter. Measurement must be taken at point “A” (4) 2-1/2 in. (64 mm) from top of cylinder bore (2). If any cylinder exceeds specifications (table 2-2 or 2-3) by 0.005 in. (0.127 mm) or more, repair cylinder or replace engine. NOTE If cylinder block inspection indicated that the cylinder block was suitable for continued use except for out-of-round, taper, or minor nicks or scratches, it can be conditioned by honing or boring.