TM   5-2815-241-34&P Section  XVI.  FINAL  TESTING,  ADJUSTMENTS,  AND  TROUBLESHOOTING  ON  ENGINE TEST STAND Page Page Final  Testing  and  Adjustments.. ............. 2-414 Troubleshooting   on   Engine Scope  ........................................................ 2-414 Test  Stand.. ............................................. 2-424 SCOPE Engine testing and break-in are performed on a suitable engine test stand. Make sure engine test stand  capacity  is  sufficient  to  allow  testing  at  100  percent  engine  horsepower.  Engine  testing  and break-in are accomplished simultaneously. Break-in on a rebuild engine is necessary to provide an operating period for moving parts and mating surfaces to reach a full seat. Final testing helps detect potential  problems  and  establishes  a  period  for  final  adjustment  for  best  engine  performance.  During final  testing  make  the  following  checks  frequently.  Lubricating  oil  pressure  should  remain  at  a  con- stant  figure  with  engine  at  speed  and  load  after  operating  temperature  has  been  reached.  Abnormally high or low oil pressure may indicate a problem. Oil temperature should not rise above 225°F (107°C). Shut down engine and diagnose problem(s) before restarting engine. Do not allow oil to go above high mark or below low mark on oil level dipstick. After engine is started, add coolant as necessary to completely fill cooling system and replace en- trapped air. Coolant should not exceed 200°F (93°C), or drop below 160°F (71ºC) during engine operation. Allow engine to idle for a few minutes before shutting down after a load run. Engine blowby readings must be taken frequently during run-in to note any blowby increase at a given speed and load. If there is any indication of blowby increase, engine speed must be reduced for a few minutes and then brought back to the original setting. During each power check, if blowby pressure rises, more run-in is required. With engine running at governed speed at 96 to 100 percent rated horse- power,  crankcase  pressure  should  not  exceed  12  inches  (30.48  cm)  of  water.  If  crankcase  pressure exceeds this figure, operate engine at 96 to 100 percent rated load and rpm for 30 minutes, If there is no  rapid  change  in  excess  of  2  inches  (50.8  mm)  of  water,  and  reading  does  not  exceed  12  inches (30.48 cm) of water, blowby is acceptable. Engine troubleshooting is included to further aid in locating  faults  found  during  final  testing. FINAL  TESTING  AND  ADJUSTMENTS This   task   covers: a. Procedures Before Starting b.  Starting  (page  2-418) (page  2-415) c. Engine  testing  (page  2-419) INITIAL   SETUP Tools Tools  -  Continued Hammer,   ball-peen,   8-ounce Handle,   ratchet,   1/2-inch   drive Measuring  device,  fuel  consumption, ST-1190 Pump,  priming Punch,    1/4-inch Screwdriver,    flat-tip,    1/4-inch Socket,  hex  key,  1/2-inch,  1/2-inch  drive Test  stand,  engine Tool,   blowby   checking,   ST-487 Wrench,   box-end,   9/16-inch Wrench,   open-end,   9/16-inch Wrench,   open-end,   5/8-inch Wrench,   open-end,   3/4-inch 2-414 Change  1