Page 236 - Practical Machinery Management for Process Plants Major Process Equipment Maintenance and Repair
P. 236

218  Major Process Equipment Maintenance and Repair

                          Check Condition and Clearance of Main Bearings. Inspect bottom of
                          crankcase for signs of bearing materials. Visually inspect each main
                          and crank bearing for signs of bearing failure without removing. Use
                          this information as a guide to  determine additional work, if  any.
                          Measure and record radial clearance on all main and crank bearings.
                          Use feeler gauge and/or dial indicator gauge with jack as needed.
                          Determine that all lateral lines from main oil header to bearings are
                          in good shape and that each fitting connection is tight.
                          Check Flywheel for  Tightness on  Crankshaft. Torque all flywheel
                          bolts. Visually inspect contact area for fretting. If fretting is occur-
                          ring, remove flywheel, clean and inspect contact surfaces. Reassem-
                          ble and torque all bolts.
                          Check Condition and Clearance of Crosshead Slippers. Visually in-
                          spect each crosshead slipper for signs of bearing deterioration. Use
                          feeler thickness gauge to check clearance between upper slipper and
                          crosshead guide without removing. Record this clearance.
                          Check Condition and  Clearance of  Crosshead Pin and  Bushing.
                          Without removing, visually inspect crosshead bushing for signs of
                          deterioration, Using dial indicator and bar,  shift crosshead and re-
                          cord movement or slack in bushing. If excess clearance is found, pull
                          pin and bushing as needed.




                                            Upper PortionlCylinders

                          Check  Condition and  Clearance of  Power  Piston Articulated Pin
                          Bushings. Visually inspect bushings for signs of  deterioration. Use
                          dial indicator and bar to measure clearance. If excessive clearance is
                          indicated, change out bushing and/or pin.
                          Check Camshaft and/or Luyshft Drive Chin. Adjust idler to tighten
                          chain when needed.
                          Check Wter Pump Drive Chain Tightness.
                          Check Lobes, Camshaft, or Crankshufi. It is not intended that any
                          disassembly of the camshaft box be made to complete this preventive
                          maintenance step. Instead, only measure and record the normal lift
                          of the valve stem at the top of each power cylinder head. Measure-
                          ment is visual, using a steel scale. Observation of such measurements
                          should be recorded to the nearest 1/16 in. Note:  “Normal” or “stan-
                          dard” lift should be the same for all valves for a specific model and
                          type engine.  Deviations from this value are an indication of worn
                          lobes on the camshaft, and appropriate repair steps should be initi-
                          ated.
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