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.