Analyzing oil from a Ford NASCAR engine that won a 500-mile race in the late ‘90s
Editor’s Note: This story has been on hold for a few years, but I’m happy to share it now.
Did you ever wonder what the racing oil from a Ford NASCAR engine looks like after winning a 500-mile race? Ever wonder what kinds of debris and impurities could be found in that used vintage oil?
In the summer of 1998, Valvoline sent out two small vials of 20W-50 synthetic oil to select members of the media as part of an awareness campaign for the new racing lubricant. One vial was filled with fresh oil, the other was a sample taken directly from the oil reservoir of Mark Martin’s Taurus after he won the California 500 race at Fontana in early May of that year.
Back in 2018, I was talking to Lake Speed Jr., who is the founder of SPEEDiagnostix, an oil-analysis company based in Concord, North Carolina. Speed is a certified tribologist and has helped formulate lubricants for NASCAR teams and other racers. He’s also well known in his technical role at Total Seal.
While discussing the benefits and science behind oil analysis, I mentioned that I had the Valvoline samples in the back of a bookshelf. Would he be interested in analyzing 20-year-old used racing oil? Of course, and the vials were shipped to Concord the next day.
Oil analysis has been around since the late 19th century when the blotter spot test was used to inspect for color, viscosity and contamination. After WWII, railroad locomotives were experiencing high rates of failure. Engineers adapted elemental spectroscopy to determine the level of wear metals in lubricants, in addition to contaminants.
The test equipment evolved significantly over the years, moving to infrared spectroscopy and now to atomic emission spectroscopy (AES)—which is the technology used at SPEEDiagnostix. The equipment there has been dedicated for analyzing racing oil; whereas, oil analysis enterprises designed for fleets or diesels rarely have the same precision.
Basically, the oil is burned with a high-heat source such as plasma or an electric arc. Every atom in the oil emits light when burned, and photo cell in the test equipment captures and analyzes this spectrum of light. Iron, copper and other metals all emit a different wavelength, and the intensity of that light will indicate the parts-per-million of that metal in that particular oil sample.
“Couple these readings with the known metallurgy of the engine, and it gives you an accurate read on the health of the engine,” says Speed. “A good example is, if you see copper, tin and lead all at elevated levels—then you know you have bearing wear.”
The analysis also gives a readout of the condition of the additives in the oil, such as magnesium, zinc and molybdenum. Factored with the vehicle mileage, number of laps or number of passes down the dragstrip, the engine builder can better determine oil-change intervals.
So, what was the analysis of Martin’s oil after 500 miles and some 25 years? First, let’s review the race. Martin qualified third fastest, won the 250-lap event by 1.287 seconds over Ford driver Jeremy Mayfield. Average speed was 140.22 mph.
1998 was the year Ford introduced the D3 and started testing it, but it wasn’t approved by NASCAR until 2003. The D3 retained the Ford Motorsport R452 cylinder block tooling from the C3 engines, but casting was upgraded compacted graphite iron (CGI). Rules limited the engine to a 12:1 compression ratio, solid-lifter camshaft and single four-barrel carburetor. The oil system featured a 5-stage dry-sump pump and a 5-gallon reservoir. Martin was running the C3 on the high-speed 2-mile oval at that early race because the D3 was still being rolled out. News reports from that era are scarce on those types of details.
In analyzing the Valvoline oil from that race, Speed opted to run similar tests on two samples of modern Driven 0W-20 oil. One sample was fresh and the other was from a 2018 Xfinity engine after a 300-mile race.
“These results are very interesting! The wear levels of the modern oils are much lower, despite the viscosity of the current oil being much lower than the oil in 1998,” says Speed. “Both oils are full synthetic formulas containing Ester-base oils. Another item of note are the lead levels. Back in 1998, the engines used 76 Supreme 114-octane leaded fuel, and today (2018) they use Sunoco E15 unleaded fuel.”
In comparing the results, the older Valvoline 20W-50 lost a considerable amount of viscosity (from 20.28 cSt down to 16.55 cSt) compared to the modern 0W-20, which lost less than .1 cSt of viscosity.
“Big shearing versus the modern oil,” notes Speed. “The old 20W-50 oil started off thicker, and it sheared down quite a bit. While the old oil was twice as thick as the modern oil, the wear rate of the thinner, modern oil is almost half of what it was with the old 20W-50.”
These numbers are a strong endorsement that the quality of racing oil has improved significantly in this century, as well as the quality of materials making up the engine’s internals. Conventional wisdom suggests that a heavier oil will provide better lubrication, but modern race engines with tighter clearances and a higher quality, yet thinner, oil can still provide protection while reducing friction
“What is surprising about these results are how the differences in additive chemistry and viscosity compare to the actual amount of wear,” says Speed. “That 1998 20W-50 is a textbook example of the thinking of that time – go thicker and add more calcium, magnesium and ZDDP. Obviously, there’s a big difference in the additive chemistry of the 2018 0W-20 – No magnesium, way less calcium, slightly more ZDDP and tons of molybdenum. These two oils could barely be more different than this.”
Sharp observers may note that the concentration of select additives actually increased throughout the race.
“Oil is a combination of different molecules and you’ve got smaller molecules that are more volatile, longer molecules that are less volatile,” explains Speed. “The light part of the oil will evaporate off; that is, you’re consuming oil but you’re not necessarily consuming the additives. So it’s not completely abnormal for some of the additives to increase in concentration over the course of the race.”
On a similar topic, the Valvoline press release that accompanied the vials noted that oil color is not necessarily an indication of oil life. Additives and base oils determine oil color. The additives may be designed to keep dirt and combustion byproducts suspended in the oil to keep them from depositing on vital engine parts. Therefore, oil may start to darken after a few miles, even though there’s plenty of life remaining in the formula.
Digging into the wear metals of the used oil analysis report, it’s clear that the modern Toyota Xfinity engine produced much less wear than the old Ford engine despite the Toyota engine using an oil with half of the viscosity as the C3 engine.
“The wear rate in the Ford C3 engine with the 20W-50 was 14 ppm per 100 race miles, but the Toyota engine with 0W-20 produced a wear rate of only 8 ppm per 100 race miles,” notes Speed. “This is the beauty of used-oil analysis – the ability to measure and compare wear rates. No more guessing or speculating. We can make decisions based on data instead of theory.”
In light of today’s high-power density, turbocharged direct injection engines, Speed sees another interesting comparison.
“The additive package in the 1998 race oil would not come close to passing today’s API SP oil rating, which is designed for turbocharged direct-injection engines. The calcium levels would cause it to fail the LSPI (low speed pre-ignition) tests,” he explains. “However, the 2018 race oil chemistry is much closer to what you can find on the shelf today. Granted, the ZDDP levels in the 2018 race oil are too high and the calcium levels are too low for street use, but with just a few tweaks it could pass the modern engine oil tests. In fact, that 2018 race oil is much closer in chemistry to the 0W-8 that came from Toyota in my daughter’s new Corolla than that 1998 oil.”
Bottom line: all of this goes to show how far race oil technology has come in just a couple of decades, and how racing has yet again led the way for the technology used in passenger cars.