As with any marine engine, it’s important to maintain regular oil change intervals. Most mechanics suggest 100-200 operating hours as the safe extent of oil life in a modern, high compression diesel engine. The Gardner aboard Sandavore is anything but modern. Conversations with our local mechanic and Gardner Marine Diesels UK reveal that the engine is designed for continuous duty, meaning that oil changes could be effected while the engine is running (with appropriate oil tankage). Maybe up to 500 hours between changes. But, being the compulsive nerd that I am, I decided to maintain a 100 hour interval, with analyses. I noticed that the oil quantity was a high as time progressed last season; I wondered if I had overfilled the case when I did the first oil change. By the time 100 hours was reached, it was about 2.5 quarts high. Oil analysis revealed a high level of diesel fuel in the oil. Not good: diesel causes the viscocity to thin, which provides less lubricity between the piston rings and cylinder walls, resulting in “scouring”. An email exchange with Michael Harrison @ Gardner proved an excellent start to the investigating process- the injection system return line was leaking into the top of the cylinder head, and the resultant fuel was scavenging down with the oil. So began a 3 month-long process of discovering several things about this this particular line: 1. When made, the factory enthusiastically chromed every bit of it, including the heads that fit into the injectors (which eventually welcomed cracking, see image below); 2. Constructed of mild steel, it was prone to internal corrosion, especially if the engine sat for long periods inop; 3. Which led to the discovery that at least 50% of the line was frozen solid with hard, blackened rust & sludge; 4. These lines were custom-built for every individual engine, necessitating fabrication for replacement. My heart sank as all of this set in over a 4 week period. However I discovered the immense value of an old-school machine shop. When I brought this impossibly twisty line to Bill @ Miramar Machine in Anacortes, his answer was immediate: “well this looks fun!” Bill had to fab both the mandrels and the tooling to make all the bends in the line, then silver solder the output heads to to the main line. It took several back & forth trips to get the line to fit, but Bill was accommodating and rolled with it. Video footage shows the line installed while the engine is operating. So happy for the immense assistance and perserverance of experts!
injector fitting with chrome flaking