20-3. CYLINDER HEAD REPAIR (CONT)
d. Inspection (Combustion Surface and Top Deck).
Follow these general precautions whenever using these methods of crack detection to
prevent personnel injury. Never shine the black light directly into the eyes. Do not smoke
or eat while using inspection chemicals. Avoid getting chemicals on clothing. Avoid
inhaling spray mist, airborne powder dust and solvent vapors.
ventilation. Store chemicals away from open flames and sources of heat. Failure to
comply may result in injury to personnel.
Fluorescent penetrant inspection, using a black light, is the most desirable procedure for
inspecting components for indications of cracks. The high intensity black light and fluorescent
chemicals will identify cracks not normally found with other methods.
Use one of the following three methods to check for cracks on the combustion chamber surface.
Metal spray process can be used to restore (build up) gasket contact surfaces to original
(1) Liquid Fluorescent Inspection.
Black light and test kit shall be in accordance with overhaul contract requirements.
(a) Thoroughly clean surface to be inspected.
(b) Spray cleaner/remover fluid on cylinder head to remove any contaminants from surface to be checked.
(c) Spray penetrant on surface to be inspected. Allow penetrant to remain on surface for five to 30 minutes. This
will allow penetrant to enter the smallest cracks.
(d) Remove excess penetrant from surface.
Penetrant can be removed by washing with water or by using moist and dry paper towels to wipe
surface clean. Care should be taken not to overwash surface. Surface must be dry and free of
penetrant. Check surface with black light to see if chemical has been removed.
(e) Spray developer on dry surface. Coat entire surface with developer. Low pressure air can be used to improve
drying time. Once developer has been applied and is dry, a minimum developing time of ten minutes is
required. During this time developer will draw penetrant out of cracks and to the surface.
(f) Check surface with black light to highlight location of any damage. Black light should be measured to assure
correct output of 800 micro watts per sq mm at the part surface, 15.0 in. (38.1 cm) away from 125 watt bulb.