VALVES AND SPRINGS MAINTENANCE - CONTINUED
CLEANING AND INSPECTION
Solvent cleaning compound MIL-PRF-680 Type III is an environmentally compliant and low toxic
material. However, it may be irritating to the eyes and skin. Use protective gloves and goggles. Use in
well-ventilated areas. Keep away from open flames and other sources of ignition.
Particles blown by compressed air are hazardous. DO NOT exceed 15 psi (103 kPa) nozzle pressure
when drying parts with compressed air. Use a maximum of 30 psi (207 kPa) when cleaning compo-
nents. DO NOT direct compressed air against human skin. Failure to follow this warning may cause
injury or death. Make sure air stream is directed away from user and other personnel in the area. To pre-
vent injury, user must wear protective goggles or face shield.
Clean all parts with solvent cleaning compound.
Dry all parts with compressed air.
Inspect and replace retainers and rotors if cracked, broken or worn.
Use a spring tester to inspect and replace springs if cracked, broken, distorted or spring pressure is less than 71 lb (32
kg) when spring is compressed to a height of 2.165 in. (55 mm).
Inspect and replace intake and exhaust valves if cracked, broken, scored, grooved, warped, burned, pitted or valve head
Use micrometer to measure diameter of valve stems. Measure stems in three places. Replace valve if stem diameter is
less than 0.3704 in. (9.4 mm).
Use vee block holder and dial indicator to measure valve face and stem runout. Replace valve if runout exceeds 0.0006
in. (0.015 mm).
Measure valve head diameter. Replace if intake valve diameter is less than 1.771 in. (45 mm) and exhaust valve is less
than 1.646 in. (42 mm).
Measure valve lip margin. Replace intake valve if less than 0.099 in. (2.5 mm) and exhaust valve if less than 0.080 in.
Inspect and replace valves if retainer grooves or stem tip is worn.