follower  fails  to  revolve  and  the  cams  wipe  the  same INSPECTING AND REPAIRING surface each time the camshaft revolves. CAMSHAFTS Normal   use   will   cause   surface   disintegration, usually as the hardened surfaces begin to fatigue. The condition  is  aggravated  by  abrasive  particles.  Nicks  and dents on rollers will also cause disintegration. You must make constant checks for defective rollers or  surfaces  and  for  nicks,  scratches,  or  dents  in  the camshaft. Whenever you find a defective cam follower, you should replace it. In roller-type cam followers you must  replace  a  worn  cam  follower  body  and  guide  or roller needle bearings (if used). Defective or poorly operating valve adjusters allow clearance or lash in the valve gear. Noisy operation of a lash adjuster indicates that there is insufficient oil in the cylinder  of  the  unit.  When  you  discover  a  noisy  lash adjuster and the oil supply or pressure is not the source of trouble, remove and disassemble the unit according to the manufacturer’s instructions. Since   the   parts   of   lash   adjusters   are   not interchangeable,  disassemble  only  one  unit  at  a  time. Check for resinous deposits, abrasive particles, a stuck ball  check  valve,  a  scored  check  valve  seat,  and excessive   leakage.   Carefully   wash   all   parts   of   the hydraulic lash adjuster in kerosene or diesel fuel. Check such parts as the cam follower body, plunger or piston, and hydraulic cylinder for proper fit. Camshafts can be saved when the cams alone are damaged, if the cams are of the individual type, since such cams may be removed and replaced. Figure 3-17 illustrates  the  method  of  removing  an  individual  cam from  its  shaft. When you remove a camshaft from an engine, clean it thoroughly with either kerosene or diesel fuel. After cleaning  the  shaft,  dry  it  with  compressed  air.  After cleaning the cam and journal surfaces, inspect them for any signs of scoring, pitting, or other damage. When you remove or insert a camshaft through the end of the camshaft recess, rotate it slightly. Rotating the camshaft  allows  it  to  enter  easily  and  reduces  the possibility of damage to the cam lobes and bearings. After you visually inspect a camshaft, place it on V-blocks and measure the shaft runout by using a dial indicator.   When   you   measure   the   runout,   take   the out-of-roundness   into   consideration.   Compare   your measurements   to   the   manufacturer’s   specifications. Also,  measure  the  camshaft  bearing  journals  with  a micrometer.  Figure  3-18  illustrates  a  camshaft  with bearing  journals. A  camshaft  needs  to  be  replaced  if  the  following conditions  occur: 1.  The  lobes  are  damaged,  as  lobes  cannot  be repaired. 2 .    R u n o u t    e x c e e d s    t h e    m a n u f a c t u r e r ’ s specifications. 3. Wear on the shaft bearing journals exceeds the manufacturer’s specifications. 4. The keyways are damaged. Figure 3-18.—Camshaft with bearing journals in a V-type engine. Figure 3-17.—Removing an individual cam. 3-13