My first introduction to Cat Marine diesels was back in the mid-1970s in the merchant navy, where both ships I served on each had two 1000 hp Cats coupled to alternators for our onboard electrical needs. During the time I spent aboard these ships we never had any problems with the direct-injection Cats, which started instantly when needed and did everything asked of them.
Incorporating electronic management into a Cat diesel makes an engine that virtually has no peers! This is because the Electronic Control Modules (ECM's) used have load and barometric pressure sensors which ensure that injector fuel spray timing is correct across the entire rev range and the air/fuel mix is maintained at the optimum ratio for complete combustion, including the periods before, during and after turbo boost.
ECM-controlled unit injectors ensure complete combustion in each cylinder, yet these are as easy to change as sparkplugs!
As readers of Trade A Boat's sister publication Trailer Boat know, I'm a big fan of electronic management systems in marine engines. Providing they're fully waterproofed, cooled effectively and isolated from engine vibration, there's no logical reason why a system should ever fail. For example, Cat ECMs are sealed to operate at a depth of 21 metres!
Random Cat testing also subjects ECM diesels to extreme heat, cold, vibration, dust and electromagnetic interference under controlled conditions to simulate real life situations.
It's this reliability that Cat has been trying to emphasise to potential users of its electronically-controlled models, because ECMs do more than just maintain an engine at peak operating efficiency. They also have a memory function that records problems such as faulty fuel injectors and the resulting incomplete combustion in one of the cylinders.
The system is known as Caterpillar Engine Vision and records engine hours, fuel consumption and load factor, such as hours spent idling in a specific period of time.
Sensors placed at strategic points around the motor update information to the engine operator 20 times per second and through a modem and satellite uplink (Satcom) this information can be relayed to a shore station. So should a problem arise at sea the ship owner can arrange for service personnel to meet the vessel when it docks, saving a lot of downtime.
Customised warnings, de-ratings or shutdowns alert engine operators to nonstandard operating conditions, assisted by a facility in each engine that follows programmed engine protection strategies and even has back-up sensors. These will take over engine operating functions in the event of primary sensor malfunction.
The ECM sensors will also pick up inlet air and fuel supply restriction, low oil pressure, abnormal crankcase pressure and exhaust temperature and overheating of the engine coolant and transmission oil.
Electronic control enables multi-engine installations to be easily synchronised and even a single throttle used if required. It also ensures each engine maintains steady revs according to the throttle setting.
Of course, electronic control is only one facet of the Cat philosophy to building engines and components such as the forged, one-piece crankshafts which are tested up to 30% over designed loads to ensure reliability. Wet cylinder liners are standard and valve rotators extend valve life. All models have reliable pushrod valve actuation, and vee-block models have twin turbochargers for maximum efficiency.
As expected of engines designed essentially for heavy duty operation, Cats have extended service intervals, but obviously components such as the water-separating fuel filters, and the oil and coolant levels should be checked daily.
For example, with the straight-six 3196 the zinc anodic rods in the cooling system should be checked and/or replaced every 50 operating hours or 1900lt of fuel used. The first real service work (such as changing the engine oil and filters, draining water from the fuel sedimenter and testing for coolant additive concentration) is recommended at 250 hours or 9500lt.
These figures are based on the oil sump capacity of 28lt which is consumed at the fuel/oil ratio of 339:1 and an average fuel consumption of 38lt/hr. The straight-six 3406E has a 49lt sump which allows for 13,600lt of fuel consumption (278:1 and 55 lt/hr) and the V12 3412E a 68lt sump for 19,000 litres (279:1 and 76lt/hr average). Cat Marine recommends using oil consumption as the best indicator of oil change intervals.
However, I would add that the engine oil and filters should be changed every six months if less than 250 hours are clocked up in this period. As most operators know, turbo-aftercooled diesels are prone to 'dirtying' their oil far quicker than naturally-aspirated ones.
A full overhaul is recommended every 10,000 hours.
The 3196 and 3406E models listed below are available in a range of ratings according to anticipated engine usage. 'A' ratings equate to heavy duty usage when the engine is operated at rated load and speed up to 100% of the time. 'C' ratings are for higher speed vessels such as tuna trawlers and displacement hull motoryachts, while 'E' ratings are for planing hulls such as gamefishing boats and harbour patrol vessels.
For propshaft horsepower, reduce the maximum output by 3%. The average fuel consumption is taken from propeller power curves at maximum torque.
The 3196 displaces 12.0lt, weighs 1177kg for the engine only and is available in three separate ratings from 570-660 hp, while the 3406E displaces 14.8lt, weighs 1590kg and has five separate ratings from 450-800 hp. As of April 1999 when this guide was compiled no ratings information was available on the 3412E, but this model develops from 900-1400 hp at 1800-2300 revs.