Test Drivers

The common thread in these oil upgrades is that each requires new engine sequence tests and heavy investments of time and cash. As with previous upgrades, the industry is finding that evaluating engine oil performance is one of the mostly costly aspects of product development.

Why are engine tests needed? While many feel that laboratory bench and chemical tests should be employed – since that is where the most control over performance parameters can be achieved – the plain fact is that an engine oil does not live and operate in a glassware beaker. It operates in an environment of multiple metals, extreme temperatures, and mechanical as well as chemical forces.

The logical choice then is to test the oil in an actual engine. So how does one go about doing that? Should the engine be in a vehicle driving over a standard course for a set period of time? Should it be normal roads, a closed course or a dynamometer? Should it test just one parameter at a time, or could a specially designed engine test a variety of parameters?

In fact all of these have been tried as well as other ideas. What has evolved is much more complex and yet serves the automotive industry, the additive suppliers and the oil marketers very well. However, it is not without its pitfalls and challenges.

Early Days

The earliest engine tests came from the U.S. military, as both the Army and Navy required oils to meet specific engine test requirements. These were run in single-cylinder laboratory engines designed to identify key oil properties, such as the ability to fight bearing corrosion and piston deposits.

The U.S. Army issued its first engine oil specification (2-104) in 1941, which is not surprising given the military needs of that time. After World War II, they and others continued to use the military designations, which mostly focused on the needs of diesel-fueled engines.

By the early 1950s, passenger car manufacturers as well as oil marketers began to see serious problems with the products in use. This led to the development of the American Petroleum Institutes oil service classification system and ultimately to the MS engine test sequences. These were the first in a long series of engine tests and included General Motors Sequences (originally I, II and III), Chryslers Sequence IV, and Fords Sequence V.

With the advent of standardized tests, ASTM was tapped to assure that the tests were reproducible and repeatable. Another party joined the effort too: the lubricant additive companies. They brought their specific knowledge of engine oil performance to both the oil marketers and the engine builders.

Beginning in the 1960s, engine oil standards began to become more severe, and oil marketers resorted to meeting both the API MS sequences and certain military specifications. However, each vehicle manufacturer had specific oil performance issues that were important to them. Soon, each original equipment manufacturer was imposing additional tests in order to meet its oil requirements, such as the Ford Falcon Rust Test.

A Level Field

Finally in 1971, to give all oil marketers the same playing field and address myriad OEM concerns about performance, API devised a more all-encompassing standard. It established the API S and C series of categories to designate oil performance. S stands for service oils for passenger cars; C indicates commercial oils for heavy-duty diesels.

At this point emerged what came to be known as the Tripartite, made up of API representing oil marketers, SAE (and later ILSAC) to speak for the auto industry, and ASTM to bring forward the necessary standardized tests. The additive suppliers supplied the chemical tools needed to successfully protect engines, and independent laboratories provided objective, third-party oil evaluations.

The Tripartite was the brain child of Chuck Colyer of Amoco Additives (and later Lubrizol), and was intended to put a cohesive process in place for oil development. It established SAE as the group that would identify the technical need for a new category of oil, ASTM to develop needed tests and identify limits, and API to develop user language and category designations.

There was one unfortunate flaw to this system: Additive and oil companies could be involved in each leg of the Tripartite – via membership in ASTM, SAE and API – while OEMs could only join the first two. The result was some concern about whether the effort was in fact balanced.

In the early 1990s a revised process was introduced to address this sensitivity. Formally spelled out in the Engine Oil Licensing and Certification System (API Document 1509), it was the joint creation of API, ASTM and various North American and Japanese automakers. The auto and oil industries at last had a process in place for jointly developing engine tests and setting test limits. In recent years, this has evolved further into the Auto/Oil Advisory Panel, which works on light-duty oil development, and the Diesel Engine Oil Advisory Panel to manage the heavy-duty side.

Who Needs This Test?

Engine test development can begin with any of the various concerned parties. Typically though, the OEMs have been the source of new or revised tests since they are in the best position to see potential field problems or shifts in engine designs.

Don Smolenski, formerly with General Motors and now the North American OEM liaison manager at Evonik Oil Additives USA, said, New tests are sometimes in response to field issues – the so-called basket of failed parts – but most new tests are due to hardware obsolescence. Engines go out of production so [parts] wont be available much longer. He also perceives a more recent trend for OEMs to be proactive on oil issues, to head off problems before they arise in the field. For example, higher specific output engines may see higher oil temperatures overall, which means that OEMs will need oils with better oxidation stability. This increased robustness, not incidentally, will allow for longer oil drains among other needs.

If the new test is needed due to engine obsolescence, the OEM will try to estimate the remaining life of the current test and project when the new test must be ready. Typically they will notify the industry at least two to three years out, Smolenski continued. The OEM will likely engage the ASTM Surveillance Panel as soon as they have a draft procedure to check out. A replacement test will probably have fewer issues with acceptance – its likely to be a must-have. A new test will see more scrutiny.

Automotive lubrication expert Bob Olree, also formerly with GM, observed that a performance problem can show up either in engine development or in the field, and wherever it does, automotive engineers frequently think it must be oil related. Then the fuels and lubes engineers are called in and told to fix the problem, Olree said. Nine times out of 10 the problem is not oil related.

Sometimes it is, though. Olree pointed to an incident where GM ran into start-up lifter noise problems with a new, highly advanced valvetrain used in its LS series V8 engine. GMs investigations took about 10 weeks and clearly showed that the problem was oil aeration. The effects weres much more severe with some oils than others and vehicle tests clearly separated the oils into good and bad.

GM alerted the industry to the problem and asked for help in solving the aeration problem, Olree recalled. The industry answer was that its a GM problem and GM would have to solve it itself. GM went on to do just that, developing a new oil aeration test at Southwest Research Institute, the San Antonio, Texas-based independent laboratory. A new version of this test will be part of next years Dexos1 upgrade.

A Slew of New

Olree pointed out that most of the previous ILSAC oil upgrades only needed revisions or updates of older tests. GF-6 is diverging from that, he said, by requiring several completely new tests to be created. However there is much to do before these are voted into GF-6 by all the interested parties.

By contrast, Olree said, GM working alone has developed several new tests for inclusion in the revised Dexos specifications, all proprietary. I guess the fact that GM can develop tests to address aeration, turbo deposits and LSPI [low speed pre-ignition] as proprietary tests but the industry cant, says that the problem seems to be in the industry process, Olree said.

For Dexos, GM also is designing a new wear and oil thickening test to replace the ASTM Sequence IIIG test, because the IIIG uses an older GM engine that isnt made any more. However, it apparently does not intend to advance the replacement test to ASTM for industrywide precision and test monitoring, which is a must-have for inclusion in any ILSAC or API category. Thus, a different oxidation test has to be developed for GF-6.

Here are the three new engine tests that are slated to be in GF-6 and API SP, as outlined at the Auto/Oil Advisory Panel meeting in June.

The Chrysler Oxidation Test. This test is very close to being ready for matrix testing, with test stands in place at Southwest Research Institute and Intertek, also in San Antonio. The test shows good correlation to Las Vegas field trials, and it measured reduced volatility and oil consumption effects. But it may necessitate some change in data interpretation. For example, oil addition during the test is less than one-third of whats needed in the IIIG; after correcting for that, Chrysler says the test does correlate with the older one.

Fords Low-Speed Pre-Ignition Test. Ford said it has finished the Design of Experiment for how this test is to be run, but preliminary results are not clear. When run at Intertek, the test was able to rank different oils performance, but it only somewhat ranked oils on engine stands at Southwest Research Institute. A statistical review is under way.

Fords Timing Chain Wear Test. Good progress is seen here, Ford reported. Labs other than Ford have installed the engine test, and the automaker is close to being able to take orders for the test hardware. This test requires oil changes every 24 hours, and there is no separation in performance betweeen ILSAC GF-5 and API CJ-4 engine oils.

Tests Needing Updates

GF-6 also requires changing the conditions and limits for most engine tests now in GF-5. (Only the Sequence VIII for bearing corrosion remains untouched.) The changes typically involve new hardware or test conditions, and aim to reflect the stresses seen in modern engines as well as tougher emissions and fuel economy requirements. These tests are:

The Sequence IVB test to measure valvetrain wear will now use a Toyota engine. Toyota reported in June that the test developers are struggling with showing discrimination between good and bad oils, but test stands and hardware are in place, and three Sequence IVA reference oil are being used to fine-tune the test. The hope was to begin matrix testing at the end of August.

The Sequence VH sludge and varnish test is moving close to completion, with matrix testing also to start in August. This Ford test was showing higher fuel dilution than the VG test it is replacing, but Ford is making adjustments to solve that issue.

The Sequence VIE fuel economy test procedure is also nearly ready, and its ASTM Surveillance Panel has been asked to recommend that it move along to matrix testing. For now it will continue to use GMs 2012 model year engines, but supply of this hardware is finite so rolling up to a new engine is critical.

Engine testing is the best methodology for evaluating engine oils, and the closest to the complex environment seen by the lubricants. It is, however, still a relatively crude tool which has to be constantly monitored and adjusted to give the results that are needed to assure good engine performance using the latest engine oils.

Next month: Testing update for the PC-11 heavy-duty upgrade.