Power at Work: What's happening in engine oil analysis and recovery

Monday, August 9, 2010

Technology has evolved, so that you no longer need to impress your neighbour with the plume of smoke pouring from your truck or tractor

by RALPH WINFIELD

Some of us remember when we looked at the colour of engine oil on the dipstick and then rubbed it between two fingers to see if it felt okay – with not too much soot (carbon particles) in it. Those two criteria determined if it was uncontaminated enough for additional miles or hours of use.

The other determination was that, if the oil level increased, you checked the level of coolant in the radiator. If the coolant level was down (and the exhaust was white) you could bet your last dollar that the head gasket was blown. The defective head gasket would let coolant into an engine cylinder and some of it would go past the piston rings into the crankcase, raising the oil level on the dipstick.

The confirmation of coolant bypass was to loosen the oil drain plug when the engine was cold. If you got drips of coolant or water, you had confirmed your worst fears. Either the head gasket was blown or, even worse, the head was cracked.

As late as the1950s, my courting car, a 1955 Pontiac Laurentian with a V8 engine, did not have an engine oil filter. With a good eye and regular oil changes, that car got to 90,000 miles before a rebuilt engine was required to improve power, reduce oil consumption and stop the blue plume that followed the car. If we assume the car averaged 40 miles per hour, the running time hours would have been about 2,250.

In the 1950s, 2,000 hours on an engine prior to major overhaul was considered acceptable. As we approached the 1970s, oil quality and oil filtering improved and that figure went up to the 4,000-to-5,000-hour range.

The next step was to take engine oil samples and send them out for testing to determinethe type and extent of engine oil contaminants. This permitted truck owners and operators to evaluate the cost/benefit of extending oil change intervals to save money and time, while maintaining or extending the useful working life of an engine.

Just recently, I spoke with the owner of a diesel tractor that was approaching 9,000 hours of operation. The injectors had been serviced, but neither the oil pan nor the head had been removed. However, he did admit that the tractor was now, like the man himself, in semi-retirement.

What next? We now have car engines equipped with "fluid property sensors" in the crankcase oil. The sensor indicates to the operator that sufficiently high levels of contaminants exist to require the oil to be changed. This might increase or decrease the normally recommended oil change interval of about 5,000 kilometres for most cars, based on driving habits. Many short trips in cold weather will increase oil contamination.

At present I am not aware of any commercial/farm diesel engines utilizing this technology. Laboratory sample reports are still providing the nature of contaminants and the possible source.

In recent years, positive crankcase ventilation has been a technique to collect bypass (blow-by) air and redirect it to the intake manifold for burning rather than discharging it into the environment. However, as engines wear, this can create a significant loss of crankcase oil and add to the exhaust emissions.

In response to the need for reduced engine emissions, at least one major filter manufacturer has developed a collection and filter unit to recover the oil from crankcase blow-by, remove soot and other particles, and return it to the engine oil sump. This could be a part of the emission control systems as we move into Tier 3 and Tier 4 engines for on-road as well as off-road applications.

Fifty years of improvement. Both engine manufacturing and oil formulation technology have advanced significantly. Fortunately, tractor, truck and combine operators have also taken a giant step forward. They no longer attempt to impress the neighbours or other observers with a plume of black or blue smoke that could be produced when on a power trip!

Technology, legislation and common sense have collectively prevailed to help reduce our negative impact on the environment, while we continue to produce more food with less fuel and engine oil. BF

Agricultural engineer Ralph Winfield farms at Belmont in Elgin County.