Oils run the gamut from lower cost mineral-based oils to premium-priced semi-synthetics and full synthetics.
“Synthetic blends and fully synthetic oils cost more, but they offer value-added benefits that may offset the cost,” says Reginald Dias, director for commercial products, ConocoPhillips Lubricants.
There is a whole range of products currently available. “The demarcation line between synthetic and conventional oil is not distinct,” explains Ken Cicora, off-highway marketing advisor, ExxonMobil. “Totally conventional mineral oil is on one extreme and 100% synthetic oil is on the other side. In the middle, you have these synthetic blends that are a combination of cost/benefit. Semi-synthetics might have anywhere from 5% to 20% or more of synthetic (content). Therefore, you a have a range of capabilities.”
Choosing the product that provides the maximum return on investment really depends on your particular circumstances. In many off-highway applications, a premium synthetic oil is simply overkill. While premium oils do help extend oil drain intervals when used with a well-implemented oil analysis program, dirt contaminants are often the limiting factor. “The environment is sometimes your Achilles heel to being able to extend drains past a certain point,” says Cicora.
If you get a lot of outside contaminants in the oil, you reduce its useful life. “If contamination is present, then it is likely that you would not be able to enjoy the value-added benefits derived from synthetics,” says Dias.
“A lot of general construction outfits can do very well with conventional oils,” says Cicora. “You can extend drains with conventional oil if you have a good oil analysis program and the proper maintenance practices. You are not necessarily going to a point where the synthetic will give you that much more benefit. A conventional mineral oil is capable of getting you to that point.”
Synthetics Offer Additional Benefits
But there are circumstances where synthetics are the better choice. Synthetics have a higher viscosity index and therefore they are capable of handling a wide range of temperatures. “They have better pumpability on the low end and they also keep their viscosity better at the hot end compared to standard mineral oil,” says Cicora. “In addition, oxidation stability of synthetic oils is better than mineral-based oils, so they will last longer.”
This equates to added protection for your equipment. “A lot of the wear in machinery occurs during cold starts,” says Dias. “In the first few seconds that the engine is started, the oil has to be pumped to different parts of the engine. That is critical for the initial wear. Because synthetics have good cold temperature pumpability — also because they have good film strength at high temperature — you really get excellent lubrication for a wide range of temperatures.”
With the oxidation stability making longer oil life possible, and the benefits of the wide operating temperature range, why isn’t everyone switching to full synthetics? “The customer has to be very selective in choosing the synthetic lubricant that is applicable to the operation,” explains Dias. Not all applications will benefit from their value-added properties. “We will sit down with a customer, go over the operation and do a complete value/benefit analysis. We look at the cost of the product and the benefit. We also look into the life-cycle cost based on the drain intervals.”
An example of an application where synthetics have proven valuable is the bearing on top of an asphalt plant. “This bearing sees extremely high temperatures,” notes Cicora. “It is very difficult to keep the life of that bearing, so you use synthetic lubes.”
Perhaps one of the most extreme environments is faced by Alyeska Pipeline Services Co. The firm designed and built the 48-in.-diameter, 800-mile-long Trans Alaska Pipeline System. It maintains the pipeline from Prudhoe Bay on Alaska’s North Slope to Valdez.