TM 9-2815-237-34 2-21. CYLINDER HEAD AND VALVE REPAIR (Cont’d) 9. Install valve (2) in valve guide (4) from which it was removed. CAUTION Clearance must be 0.001-0.003 in. (0.026-0.076 mm). Excessive valve stem clearance will cause excessive oil consumption and may cause   valve   breakage. NOTE l Intake and exhaust valves are available with 0.0035 in. (0.089  mm)  and  0.0137  in.  (0.349  mm)  oversize  stems. l If valve stem clearance is more than 0.0027 in. (0.068 mm), valve guide  must  be  reamed  to  next  size  and  oversized  valve  installed. If unable to produce clearance with oversize valve, replace cylinder  head. 10. Using dial indicator, measure valve stem clearance. Dial indicator must contact valve stem (1) just above valve guide (4) and at a right angle to the valve stem (1). Drop valve (2) approximately 1/16  in.  (1.6  mm)  off  valve  seat  (3)  and  move  side-to-side  when  taking  measurement. 11. Repeat steps 9 and 10 for remaining valves (2) and valve guides (4). 12. Inspect cold start advance switch (6) and engine temperature sending unit (5) for damage. Replace if  damaged. d. Refacing Valves 1. Using valve face grinding machine, grind valve face (7) on all valves (2) to 45”. 2. Maintain a minimum of 1/32 in. (0.80 mm) margin (8) on all valves (2). If margin falls below specifications,   replace   valve. e. Grinding Valve Seats 1. Using valve seat grinding kit, grind all valve seats (3) to 46°. NOTE If  valve  seat  width  exceeds  specifications,  valve  seat  width  must be  narrowed. 2. Measure width of intake valve seats (3). Valve seats (3) must not be wider than 1/16 in. (1.53 mm). 3. Measure width of exhaust valve seats (3). Valve seats (3) must not be wider than 3/32 in. (2.36 mm). 2-66