of the wiper, ready access can be gained to the back side of  the contacts. nut is tightened, avoid checking for tightness by twisting the  body of the elbow. After all plugs have been installed, torqued, and the leads  properly installed, start the engine and perform a complete  ignition system operational check. To clean the contact mating surfaces, force open the breaker  points enough to admit a small swab. Whether spreading the  points for purposes of cleaning or checking the surfaces for  condition, always apply the opening force at the outer end of  the mainspring and never spread the contacts more than  1 ⁄ 16 inch. If the contacts are spread wider than recommended, the  mainspring, the spring carrying the movable contact point,  is likely to take a permanent set. If the mainspring takes a  permanent set, the movable contact point loses some of its  closing tension and the points then either bounce or float,  preventing the normal induction buildup of the magneto. Inspection of the magneto consists essentially of a periodic  breaker point and dielectric inspection. After the magneto  has been inspected for security of mounting, remove the  magneto cover, or breaker cover, and check the cam for  proper lubrication. Under normal conditions, there is usually  ample oil in the felt oiler pad of the cam follower to keep  the cam lubricated between overhaul periods. However,  during the regular routine inspection, examine the felt pad  on the cam follower to be sure it contains sufficient oil for  cam lubrication. Make this check by pressing the thumbnail  against the oiler pad. If oil appears on the thumbnail, the  pad contains sufficient oil for cam lubrication. If there is no  evidence of oil on the fingernail, apply one drop of a light  aircraft engine oil to the bottom felt pad and one drop to the  upper felt pad of the follower assembly.  [Figure 4-58] A swab can be made by wrapping a piece of linen tape or  a small piece of lint-free cloth over one of the leaves of  a clearance gauge and dipping the swab in an approved  solvent. Pass the swab between the carefully separated  contact surfaces until the surfaces are clean. During this  entire operation, take care that drops of solvent do not fall  on lubricated parts, such as the cam, follower block, or felt  oiler pad. After application, allow at least 15 minutes for the felt to  absorb the oil. At the end of 15 minutes, blot off any excess  oil with a clean, lint-free cloth. During this operation, or any  time the magneto cover is off, use extreme care to keep the  breaker compartment free of oil, grease, or engine cleaning  solvents, since each of these have an adhesiveness that  collects dirt and grime that could foul an otherwise good set  of breaker contact points. To inspect the breaker contact surfaces, it is necessary to  know what a normal operating set of contacts looks like,  what surface condition is considered as permissible wear, and  what surface condition is cause for dressing or replacement.  The probable cause of an abnormal surface condition can be  determined from the contact appearance. The normal contact  surface has a dull gray, sandblasted, almost rough appearance  over the area where electrical contact is made.  [Figure 4-59] This gray, sandblasted appearance indicates that the points  have worn in and have mated to each other and are providing  the best possible electrical contact. This does not imply that  this is the only acceptable contact surface condition. Slight,  smooth-surfaced irregularities, without deep pits or high  peaks, such as shown in  Figure 4-60 , are considered normal  After the felt oiler pad has been inspected, serviced, and  found to be satisfactory, visually inspect the breaker contacts  for any condition that may interfere with proper operation  of the magneto. If the inspection reveals an oily or gummy  substance on the sides of the contacts, swab the contacts with  a flexible wiper, such as a pipe cleaner dipped in acetone  or other approved solvent. By forming a hook on the end  Figure 4-59.  Normal contact surface. Figure 4-58.  Felt lubricator. One drop here And one drop here 4-36 Breaker Point Inspection