Exposing the flaws in 540RAT’s “Motor Oil Engineering Test Data” blog, one flaw at a time. This has been circulated in oil related threads for as long as I can remember, and I’ve debunked this as being a useless test over a hundred times in oil discussions across social media. I decided it was time to publish an article to settle this one once and for all.
The article in question, the 540RATBlog (click for link) is a series of “test data” performed by a self-proclaimed expert. Curiously, this individual begins his article not with a technical explanation of his testing, but by conditioning you to believe everything following with a list of seemingly impressive credentials. A mechanical engineer, a patent holder, a member of two societies, and a variety of automotive pursuits. It is curious that none of these includes an STLE CLS (Certified Lubrication Specialist) certification, yet he assumes himself to be one. It is worth noting that if your technical data is sound, and your conclusions valid, you should find no need to elevate their credibility by flaunting your credentials, but I digress.
The Technical Flaws
This whole testing methodology relies on one basic flaw, that extreme pressure testing is a modern, relative, consistent, and valid way to test the performance of engine oils. To achieve this comparison, an extreme pressure machine is used to apply force to a metal surface while another spins. The amount of force that can be applied before the lubricant fails and seizes the spinning surface is recorded in PSI. The concept is very simple, and various machines designed for this purpose have been employed by shady lubricant salesmen in the past. More on this later.
The author goes through a long and over-drawn explanation as to why he believes that extreme pressure protection is the most important metric to engine oil, focusing heavily on cam lobes. This would be great, were the year 1975.
- The first and most critical note to make is that the testing methodology is kept a secret. The details and the specific test equipment, unlike with ASTM industry standardized testing equipment and procedures, which can be calibration validated and evaluated by real industry professionals, is noted as proprietary information. This is an immediate red flag, and for obvious purposes: nobody can validate the results of this testing. 3rd party validation is extremely important in a test like this one, where results can be very easily manipulated.
- Extreme pressure testing (what is conducted in this test) is not relevant to modern engines. Simply put, there are no extreme pressure conditions in the overwhelming majority of modern, mass-produced engines. We use roller cams, not flat tappet cams, and where flat tappet/bucket cams are used, valve spring weight is sufficiently low, and reciprocating valvetrain mass sufficiently light, that extreme pressure protection is not required as it was decades ago. However, don’t take my word for it.Back in 2010, there was an FAQ session over on BITOG that was published (click for link). This list of FAQs was provided by the Pennzoil Ultra team, which consisted of Pennzoil’s global brand manager, their technology manager, their passenger car motor oil technology manager, and their lubricants technology group manager. A question is asked which states, “Compared to Pennzoil Platinum®, how does Pennzoil Ultra™ do in the 4-ball wear test (better, worse, or about the same?)”
As a bit of background, Shell’s 4-ball wear test is an industry standardized test, represented under ASTM D2783. Unlike the author’s testing equipment, this is an industry standardized method that can be peer evaluated by certified industry professionals. This test is used to measure extreme pressure protection of lubricants. Pennzoil answers with the following: “The 4-ball wear test has no correlation with wear performance in an actual engine. It was developed to test industrial oil performance for roller bearings under extreme load. The test repeatability is very poor. However given the above then for an equivalent viscosity grade and anti-wear package (Industry specification controlled), then the performance can be expected to be equivalent.”Read that again as many times as you need. The 4-ball wear test, an extreme pressure testing methodology, has no correlation with wear performance in an actual engine. In short, extreme pressure testing is not relevant to modern engines! However, they note that test repeatbility is very poor. More on this next.
- The test repeatability is very poor. In order to understand how engine oils prevent wear, you must also understand the principles behind boundary lubrication and also how antiwear additives decompose. To make a long story short, antiwear additives require heat in order to decompose, at which point they cling to two metal surfaces and produce a protective layer that prevents wear in the event that the oil film would fail and the two surfaces were to meet. It’s a rather simple concept, right? Wrong.The challenge comes in two phases. First, since it takes heat to decompose antiwear additives, you must be able to measure, and keep precisely constant, the temperature of the lubricant at the point of contact at all times. ZDDP doesn’t decompose at one temperature, it decomposes in tiers. This is impossible to do with any testing methodology. Since these antiwear additives require heat, you must build that heat. The general method is to apply light pressure at first, building slowly until you place maximum pressure and force the film to fail. The duration used for applying light and medium pressure is critical, as a longer duration would build more heat and therefore decompose more additives. You cannot evaluate the performance of antiwear additives with only one temperature. While the duration may be kept reasonably consistent, it is not in the least bit representative of oil temperatures at the point of contact. An information series video presented by AMSOIL highlights this concept very effectively:
- Last but certainly not least, only brand new oils are tested. Most oils, over the course of their service interval, will be compromised in their ability to prevent wear in extreme pressure conditions. This is due greatly in part to viscosity shear; the thinning of the oil’s viscosity. As a result, this test is not representative of real-world conditions. It would be infeasible to test all of the oils on the list in a variety of conditions.
Even if a test that is consistent (his isn’t), and repeatable (his isn’t), one that is able to measure oil temperature at the point of contact (he can’t), and one that can measure performance across a variety of service intervals and service durations (infeasible) we still have to contend with the fact that extreme pressure testing provides no measure of performance in modern engines, where extreme pressure conditions do not exist. Even if you did own an engine with a flat tappet valvetrain that required the use of oils with high extreme pressure protection ability, you still must contend with the issues faced by testing an aspect of engine oils that allows for higher test results to be achieved by generating more heat between moving metal surfaces.
We should be careful not to jump on board the bandwagon of false data and blatant misinformation simply due to the lack of alternate data.