There was a time when changes in engine oil specifications could be measured by the decade. Engine lubrication improved, and older and newer models alike enjoyed the benefits. For technicians used to thinking in terms of viscosity and little else, however, changes are coming, driven by tighter emission control standards.
New oil standards aren’t new, but what’s different about GF-4 is both the changes it may bring in the types and uses of engine oils and in the “political” aspects of introducing a replacement for GF-3 so soon after the launch of that standard.
New oil standards are rarely controversial, but GF-4 as defined by the “needs statements” of the automakers may involve significant changes in the way engine lubes are formulated, changes so radical that GF-4 oils may not be backward compatible with older engines. That means more products in inventory, and potential warranty and liability issues for garages that use the newer oils in older engines, and vice versa. Is GF-3 good? The current standard has delivered a 0.5 percent fuel economy improvement, 40% less oil consumption and a 25 percent increase in oil life compared to the GF-2 oils they replaced, along with better oxidation stability and high temperature deposit protection.
Why a new standard now? According to Michael McMillan of the General Motors Research and Development Center in Warren Michigan, there are three main driving forces: One is increased fuel efficiency, initial and retained, another is improved oil performance in terms of oxidation stability, used oil low-temperature pumpabilty and reduced high temperature piston deposits, and the third and perhaps most important is environmental, according to McMillan: “Tier II emissions requirements (including 0.07g Nox/mile for 120,000 miles) will require limiting catalyst poisons such as sulfur and phosphorus.”
New oil standards on this continent are developed with input from many industry players such as the International Lubricant Standardization and Approval Committee (ILSAC), the American Petroleum Institute (API) and the American Chemistry Council. ILSAC’s oil committee includes representation from auto makers, lubricant and additive suppliers. For GF-4 the main issue is phosphorus. Phosphorus, a common chemical element found in everything from animal bones to matches, is a key component for anti-oxidation, wear additive and bearing corrosion inhibitor packages in motor oils. Unfortunately, it also poisons catalytic converters, and although the effect is slow, it is cumulative, threatening automaker’s seven-year life expectancy requirement for emissions control systems. At a July 10th meeting of the ILSAC oil committee, Ford revealed the results of a 20-car taxi test of five oils with varying levels of phosphorus and detergents. After 100,000 miles, the Crown Victoria engines lubed with 0.093 percent phosphorus deposited the substance onto the catalyst at levels between 1.5 and 2.6 percent by weight, compared to 0.05 percent from phosphorus-free oils. Emissions were measured in “direct proportion to the level of phosphorus on the catalysts”.
The test results are clear: phosphorus in the exhaust will compromise catalytic converter action over time. From a technical standpoint, this suggests that there are two ways to solve the problem: use less (or no) phosphorus, or find a way to keep it in the crankcase instead of in the exhaust. Volatility is an issue for the oil formulators, while engine design and materials selection are options open to automakers. Blowby does occur in any engine, however, and PCV systems are another entry point into the exhaust stream that can’t be changed, at least not in the near future with gasoline fuels. And without phosphorus, GF-4 oils might be restricted to newer vehicles only. The effects on the service industry would be immediate; two types of each required viscosity would have to be carried in inventory. And as the model years progressed, GF-3 oil options could be reduced as oil companies track rising demand from GF-4 vehicles.
Dealing with phosphorus
Why not just take it out? Mainly because phosphorous compounds, particularly “ZDDP” (zinc dialkyl dithiophosphate) allows current GF-3 oils to offer emissions system protection at current levels and better economy, and can reduce high-speed piston ring wear by as much as 50 percent compared to oil formulations free of the additive. Engine environments, however, are changing. Piston temperatures are increasing. There are several reasons, including increasing engine speed and horsepower, shorter water jackets, lower levels of mixture enrichment at full throttle and newer low-drag piston designs that use thinner rings and shorter skirts. High-temperature wear and deposits are serious issues for blowby-sensitive systems like catalytic converters. GM’s McMillan declares unequivocally: “General Motors will not support an ILSAC GF-4 standard which does not contain high-temperature wear protection.”
The major oil companies face an interesting dilemma in meeting the automakers needs for the 2004 model year. Full compatibility backward and forward would be ideal, but it’s unclear at the time of writing whether new additive technology can be affordably developed in the short time available. Almost all oil company majors contacted by SSGM declined to comment on the issue, citing a need to wait until the requirements solidify into a formal standard. All stated that whatever the GF-4 standards specify, the industry will have products ready that will protect the new cleaner engines. One industry player who was willing to discuss the issue was Valvoline’s senior vice-president of technology, Dr. Fran Lockwood. Lockwood, as chair of API’s Lubricants Committee, is certainly on the inside of the process, and defines the issue clearly: “The category expected timing (for GF-4) has been delayed to January 2004, so the main implications at this stage of the game, as best we know, is that it will be an oil with increased oxidation stability and targeted for improved fuel economy and better emissions system tolerance.”
Phosphorus-based additives are definitely on the agenda at API’s Lubricants Committee, and Lockwood notes that there is more than anecdotal evidence for its effects: “There is research that shows that phosphorus does deposit on the catalyst and reduce its effectiveness over a long period of time. However, it’s also known that phosphorus is an element in a class of additives for good engine wear protection. There is debate; I think that there’s enough evidence to suggest that we certainly need to look both at phosphorus and the type of phosphorus to improve the overall emission system longevity. I think it’s important that our industries work together to improve the performance of engines with respect to emissions.”
If GF-4 oils are delayed past the point of model year 2004 vehicles’ first oil changes, will engines be compromised? Put simply, no, as the catalyst poisoning effects of GF-3 additive packages take time to become a factor. One thing is clear, however: when they are available, the service industry needs to begin using them immediately on 2004 model engines and beyond to keep emission systems intact.