Most industrial engines still require regular valve adjustments (although more and more engines are fitted with self-adjusting hydraulic lifters). Here is a typical scenario relating to neglect of adjusting adjustable valves:
An industrial engine has been working hard and reliably for a long time until one day, after shutting it down for only ¼ hour, it would not restart again. A mechanic arrived 2 hours later and the engine started immediately and ran well without fail until the next time when the engine was shut down for ¼ hour again.
Cause:
The valve clearance was too small (never been adjusted). Once the engine had been stopped for ¼ hour, all heat was rising to the top of the engine and the valves (especially & typically the exhaust valves) opened in the closed position and dramatically reduced the compression. After 2 hours of waiting, the engine cooled down enough to allow the valves to close again and ensure enough compression to start and run the engine.
Remedy:
Carry out regular valve adjustment maintenance as per the owner’s manual.