CAMSHAFT KEY & KEYWAY FAILURE
3rd Jan. 05
The Ship was in port when I received a frantic call from the second engineer, and rushing to the engine room I found one of the cylinder heads of the No 2 AE smashed and water gushing up like a fountain.
On removing the damaged cylinder head, it was found that the piston was also cracked. It was obvious that the valves had come into contact with the piston. All the other cylinder heads were in turn opened up and similar damage was noted. This led us to suspect a fault in the camshaft or its drive. Eventually, the fault was traced to a damaged key and keyway on the camshaft.
Checking through the history of this particular engine, it was found that about 6 months earlier there had been an incident. One of the exhaust valve seats had broken and fallen into the cylinder damaging both the piston and cylinder head.
The failure of the key and the keyway on the camshaft was probably initiated at this point in time and the condition had progressively deteriorated with the passage of time.