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Better Mileage with Synthetic?

One afternoon a customer emailed us and said he gets better mileage when he’s using synthetic oil. To be honest, we were skeptical. If you’ve been with us long enough, you know we generally think that oil type doesn’t matter. Use Oil A for 5,000 miles and do a sample to check your metals, then use Oil B for the same miles and resample. Most people will find that their engine wears just the same regardless of oil brand. But here is an angle we hadn’t tested — is fuel economy affected by your choice of oil? We decided to try and find out.

Designing the experiment

When we first started talking about a fuel economy experiment, we came up with a lot of questions. How will we know how much fuel we’re actually using? How will we take into account tire pressure and other things that can affect fuel economy? Do we need to take into consideration the natural expansion of gas at different temperatures?

We eventually decided on the following plan. It’s probably not scientific enough for a MythBusters special, but it’s about as good as we could get without installing special pumps and meters, and it should be repeatable if you want to give it a shot in your own vehicle.

Counting miles was the easy part — we just recorded miles at every gas fill-up. Figuring the “per-gallon” was a little trickier, since we don’t really have an accurate way to measure fuel consumption.

In an episode of MythBusters where they were doing something that involved calculating miles/gallon, they took an old clunker, removed the hood, and rigged up a container that measured fuel consumption to the milliliter. That’s a little more involved than we wanted to get, especially since our guinea pigs are analysts Amanda and Alex’s daily driver vehicles.

We ended up recording the number of gallons needed to fill up at the pump. We decided to resist the urge to “top-off” the tank when filling and just stop pumping whenever the pump stopped. Is this a perfect measure of fuel usage? Certainly not. Every pump could be a little different in its stopping point depending on the day, the pump, the volume/speed of fuel dispensed, ambient temperature, and so on…but these things are impossible to control in the real world.

We decided to do ten gas fill-ups on each type of oil. With ten fill-ups, we’d have enough data to take into account some of those variables mentioned above that we can’t control. We also made a note to monitor tire pressure, though that varied so little that we thought it negligible.

Royal Purple vs. Quaker State

Amanda started with Quaker State Advanced Durability 5W/20. The price at O’Reilly Auto Parts was $5.29/quart or $23.99 for a handy 5-quart bottle, which is just perfect for her Kia, which takes 4.8 quarts of oil. She ran that oil in her car from May to June 2013. In ten gasoline fill-ups, she ran 3,703.7 miles and used 131.858 gallons, for a fuel economy of 28.09 miles/gallon.

She decided that 3,703.7 miles was too early to change her oil, so she kept running that oil for a total of 6,333 miles and changed the oil on July 27, 2013. The result was some good wear numbers (see figure 1, F66495).

On to the synthetic! Royal Purple 5W/20 costs $9.79/quart at O’Reilly Auto Parts and does not come in a handy 5-quart jug, so we ended up paying $48.95 for oil on this oil change. Amanda ran this oil from the end of July until October, going 3,829.2 miles and using 137.002 gallons of fuel, for a final fuel economy of 27.95 miles/gallon, a decrease of 0.5% compared to the Quaker State conventional.

Oil	Price/5 gal.	Miles	Gals.	MPG
Quaker State 5W/20	$23.99	3703.70	131.89	28.08
Royal Purple 5W/20	$48.95	3829.20	137.00	27.95

Amanda ran the Royal Purple a total of 14,277 miles before changing it (we’re all for getting our money’s worth out of an oil change!), and ended up with a little more wear than usual (figure 2, G22246).

The two oils are very close in terms of fuel economy, with the conventional Quaker State slightly edging out the more expensive Royal Purple. But in the spring of that year she was doing a little more highway driving than in the fall, with a few trips between Illinois and Green Bay, Wisconsin, and so on. Even so, the added cost for the oil itself almost certainly defeats any slight improvement in MPG she might have gotten. So let’s look at Alex’s numbers.

Mobil 1 vs. Mobil Super & Advance Auto Parts 5W/30

Alex spent $34.85 for five quarts of Mobil 1 Advanced Fuel Economy 0W/30 at Wal-Mart and ran the oil from January 2013 to May 2013. He traveled 3,061.1 miles, used 91.3 gallons of gas and ended up with a fuel economy of 33.53 miles/gallon.

Then he bought five quarts of Mobil Super 5W/30 conventional oil for $18.10 and ran 3,234.9 miles on 92.0 gallons of fuel from June to October 2013, for an average fuel economy of 35.16 miles/gallon¾a difference of 4.9% in favor of the conventional oil.

Oil	Price/5 gal.	Miles	Gals.	MPG
Mobil 1 AFE 0W/30	$34.85	3061.10	91.30	33.53
Mobil Super 5W/30	$18.10	3234.90	92.00	35.16

Alex noted that his engine tends to get better fuel economy in general in the warmer months than the colder months, so he repeated the experiment again the following year, using Advance Auto Parts 5W/30 conventional oil from February to March 2014, getting 32.93 MPG.

He then ran Mobil 1 Advanced Fuel Economy 0W/30 from May to August, getting an average fuel economy of 34.46 miles/gallon. In this case, Mobil 1 did beat the conventional oil, but his mileage still wasn’t as good as on the original run of Mobil Super 5W/30 conventional, and the added cost of the oil negates any extra miles-per-gallon.

Alex mentioned that on synthetic oil his engine seemed to burn less oil, but since that wasn’t the point of the experiment, we didn’t get too deep into trying to quantify that.

Synthetic or conventional?

So…which oil to choose? We get asked this question hundreds of times a year on the phone, in e-mails, and written on oil slips. And honestly, from a wear standpoint, we don’t find a lot of difference between conventional and synthetic oils. Some engines may run better on one than the other, or maybe you find that your engine uses less oil on one or the other, but these things are hard to quantify from our end.

There are so many factors that affect how your engine wears, what kind of mileage you get, and how long your engine will last that we could never issue a blanket one-size-fits-all statement saying “You should use X.”

We did not find that synthetic oil gave us better fuel economy, but that doesn’t mean that you won’t. Feel free to try this experiment at home and let us know what you find. Or, if you’re not experimentally-inclined and you’re wavering about what oil to use, feel free to use whatever fits your wallet. Any API-certified oil is going to be quality oil, and your engine should be happy with whatever you choose.

By Amanda Callahan|2024-09-19T10:08:27-04:00July 28, 2023|Articles, Gas/Diesel Engine|Comments Off

Antifreeze: The Silent Killer

After analyzing engine oil for 30 years, I can safely say the thing that kills more engines than any other is antifreeze seeping into the oil. We call it the “silent killer” since there is normally no indication this dreadful contaminant is about to strike until after the damage is done. Neither you nor your mechanic can see it in the oil. The dealer won’t know it’s there.

We like to say engines speak before they fail, but in this case, you aren’t likely to hear much of anything until you hear just about the worst sound an engine can make. Oil analysis is the only way of knowing this sneaky killer is closing in on you. We can see it in the oil at a trace level, long before any harm is done.

We call people daily to let them know anti-freeze contamination is about to ruin their day. A typical reaction is, “What? That engine is running fine!” And they are right—the engine will, in most instances, run perfectly well until a bearing spins, oil pressure drops, and the engine destructs to the point of no salvation.

Some engine configurations are more susceptible to the problem than others: V-6s and V-8s for instance, are perhaps more prone than other engines. But no engine is immune (except air-cooled engines!). One would think that after 100 years of building engines, the automakers would get it right. To my knowledge no one has.

The problem with design

The engineers who design engines do a marvelous job of building lighter, more efficient and faster engines. But for every step forward in the process, there are compromises.

Building lighter engines necessitates working with new alloys for the various parts that are bolted together. Gaskets are used to seal between the parts. To get an engine perfectly right, they have to use parts that expand and contract with heat at the same rate, and gaskets that are hardy enough to seal well even after they age and suffer millions of heat cycles. You can imagine the engineers tossing in their sleep while wrestling with this dilemma.

A classic example of the problem was a Jaguar in-line 6-cylinder engine I once owned. I loved that engine with its long, high-end torque curve and mellow growl. It was probably the first duel overhead cam design that managed quiet chains in the days before belts were used. But for all its wonderful assets, there was this one drawback: they used an aluminum alloy head on a cast iron block. If you managed 50,000 miles on a head gasket, you were a very fortunate person.

With an in-line design, the anti-freeze contamination usually develops at the head gasket. With the V-designs, a more common source of the problem is intake manifold gaskets.

The manifold gasket supports the air/fuel system mechanism and straddles (and is bolted to) the heads. You can imagine the complexity of the problem of heat cycles. Block expansion forces the heads up and away from the crankshaft. The lowly intake manifold is not in a position to move in concert with the expansion. It would be like trying to ride two horses standing on the two saddles.

The result of this set-up is that intake manifold gaskets fail. Antifreeze starts seeping into the oil. It often takes quite a long while before the problem manifests itself in a failure, but it can also happen quickly. Since there are usually no obvious symptoms of the problem, the unwary engine owner usually drives the engine to oblivion.

Another common question we hear is, “How long until it fails?” Unfortunately, it’s impossible to predict how long an engine with an antifreeze problem will last. Many variables factor into the equation: the type of engine, how it’s driven, the environment it’s operated in, and—the most unpredictable of all—Lady Luck. Some people can limp along for ages with a slight trace of coolant that never turns into anything serious. Others turn up a trace and then WHAM! Faster than you can say “spun bearing” the engine fails.

Don’t quote me on this, but if I had to estimate the severity of the problem in car and truck engines today—judging from our oil samples—I would suggest 1–2 % of the cars and trucks in the road today are in the process of failing from antifreeze contamination of the oil. Fortunately, most antifreeze problems can be detected early with oil analysis, and in most cases we can save the engine before a failure. We would like to save all of them. But we can’t save anything until see the oil from it.

By Jim Stark|2024-09-19T10:09:24-04:00July 28, 2023|Articles, Gas/Diesel Engine, Marine|Comments Off

The eBay Oils (Part 3)

Welcome back to the eBay Oils! If you missed the previous two installments, wherein we describe what we found in some old oils that Ryan bought on eBay, you can read them here and here.

HyVis 4 Winter

We’re going to kick this party off with an oil that I personally have never heard of: HyVis 4 Winter Motor Oil. The can looks very groovy and it has no zip code, so I’m placing it from the very early 1960s or late 1950s. It’s “Mileage Metered” and it has a picture of a medal with a ribbon on the can, so you know it’s good stuff. HyVis was apparently way ahead of the curve on extended oil use, because on the top of the can it says it’s good for 1,000 to 9,999 miles. Interestingly, the oil has zero additive in it (Figure 1). Or perhaps it’s got additive in it, just not any that we read. The grade is not listed on the can, but the viscosity came back as a light 20W. With the lack of additive it’s not surprising that the TBN read 0.0. It’s tempting to do an experiment and run this apparent mineral oil for 10,000 miles in the dead of winter, just to see what would happen. If you know of any guinea pigs, send them our way!

Amoco LDO 10W/40

Next up is a pair of old oils: Amoco and Texaco. These names remind me of gas stations we’d stop at on family vacations in the 1970s. Amoco (which he always pronounced Uh-muck-o) is the one that reminds me most of my Dad. Amoco gas stations were called Standard stations in some parts of the country, and I’ll always associate the blue, red, and white logo with long trips across the country in our green van with the velour bed and hanging beads. But Amoco did more than fill up gas tanks in the 70s–they also sold oil, and this “Long Distance” version is an SAE 10W/40. The additive package looks a lot like the Mobil Special oil we saw: heavy on phosphorus and zinc, lighter on calcium and magnesium (Figure 2). Just the right oil for a couple of bandana-wearing hippies traveling with two little kids from Indiana to Nova Scotia in 1976 in a green van with a sunset painted on the side. Ah, the ’70s.

Texaco Ursa ED 20-20W and Texaco Havoline Super Premium 10W/40

The Texaco Ursa ED oil is scant on advertising copy. They must have had their hands full designing this “Extra Duty” 20-20W oil instead. On the can they recommend this oil for everything you can think of except lawn mowers. It’s got a lot of additive in it (Figure 3), but the additives are configured more like what we’d expect out of a gear lube ¾ except with more calcium. Why the 20-20W and not just 20W? We’re not sure. Maybe it’s fancier. The viscosity read like what we see today out of a standard 5W/30. Texaco Havoline Super Premium 10W/40, on the other hand, looks a lot like one of today’s diesel-use oils in additives (Figure 4), with a normal 10W/40 viscosity.

Lucky Strike 20-20W

We knew Lucky Strike made cigarettes, but we had no idea there was an oil of the same name until Ryan found this can and bought it on eBay for $29.99. The can looks seriously old, with no information on it beyond the name, a picture of an oil derrick, and the words “One U.S. Quart.” A quick Google search revealed no real information¾just some old Lucky Strike Oil & Gas Company stock certificates from 1917. The oil probably isn’t quite that old, but it may very well be the oldest of all the cans we bought. They didn’t do a lot with additives back then, though we did turn up 125 ppm barium (Figure 5). Not a lot else was present in this 20-20W oil. Note that without any calcium or magnesium, the TBN read 0.0.

Union 76 20W/50

Union 76 20W/50 is clearly made for speed. You can tell because of the black-and-white checkers on the front. According to the lid, this oil was tested and certified by the national association for stock car auto racing. My friend Google tells me that stock car racing became popular back in the 1920s (when moonshiners were outrunning Johnny Law during Prohibition times), but this can is clearly not that old. Not only did they not make multi-viscosity oils that long ago, but the can comes from zip code 90017 so it has to be from 1963 or later. According to the can, it’s 100% parrafinic oil with selected additives, which our spectrometer reveals to be your standard line-up of calcium, phosphorus, and zinc (Figure 6). Look at that viscosity though¾it’s higher than we see in today’s 20W/50s.

Castrol R Racing

Who doesn’t love Castrol? Other oil companies, that’s who. But we like them all right, so we bought two old cans. One, with liquid tungsten, we reviewed in the first article in this series. The other appears to be much older: I’d place it from the 1940s or 1950s. Not only does this can have a high opinion of itself (“The Masterpiece in Oils!”), but they direct you how to ask for it at the store: “Do not ask for ‘XL’ or ‘XXL.’ Always state the full name.” Like modern oils, they stress the high quality of the oil with terms like “organo-metallic” that are meant impress those of us who aren’t in the oil business. I don’t know if I’d call this a masterpiece in oil work though: it looks like what we see out of ATFs these days as far as additives go (mostly phosphorus with a little zinc thrown in). Since the word “Racing” is stamped into the top of the can, the thick viscosity (like a 50W) makes sense (Figure 7).

Sinclair Dinolene 20-20W

I’ve always had a soft spot in my heart for Sinclair. The can has a picture of a dinosaur on it! This shit came from the ground, no doubt about it! Another 20-20W oil, the oil is light on advertising copy but heavy on additives. In fact, it looks a lot like recent versions of Shell’s Rotella 5W/40, except with a little less calcium. It’s much lighter than Shell’s 5W/40, though, with a viscosity reading like a 30W or a heavy 20W oil. Note the presence of lead (Figure 8).

Amsoil Super Premium 10W/40

Until I started writing this article, I had no idea that Amsoil has been around since 1972. This particular sample came, like all the rest, from a can, so it has to be at least from the mid-’80s (which is when most companies switched to plastic bottles). Even 30+ years ago, Amsoil was pushing 25,000-mile oil changes, and the can even lists a comparison between this oil and regular old petroleum as far as engine temps, flashpoint, oxidation, and lubrication range (unsurprisingly, Amsoil wins in each category!). Modern Amsoil products tend to be heavy on additives and that was true back in the day as well (Figure 9). Just for fun, we compared this oil with a virgin sample of Amsoil 10W/40 that we ran in February 2012 and they look a lot alike. The only difference is in the older oil there’s less of everything: 500 ppm less calcium, and 100-200 ppm less phosphorus and zinc. They used magnesium in the older oil, while the TBN and viscosities were nearly identical.

Pennzoil Dex2 and Z-7 10W/40

Pennzoil started as Penn’s Oil in 1913, and I have to admit, “Why the Liberty Bell?” was my most pressing question as I looked over these two old cans. Originally, Penn’s Oil came from an oil field in Pennsylvania and was christened with a Liberty Bell logo to remind users of its Pennsylvania roots. This can of ATF clearly has an earlier generation of logo on it, and Google informs me that Dexron II was introduced in 1972. This may very well have been the transmission oil that kept our green van chugging through the ’70s. There are a lot of different ATFs in stores today, though generally they have about the same additive configurations. This one is a little different in that it has more boron, magnesium, and zinc than most modern ATFs. The viscosity is right where we’d expect it to be though. Pennzoil’s 10W/40 oil can is flashy, a la the 1980s. It’s “The Motor Oil With Z-7” and although they don’t specify what that is, they do specify that “You need no extra oil additive.” So that’s reassuring. It’s rated SF-SC-CC, so I’d place it at about 25 years old. Maybe the magic of Z-7 is copper: that’s something we saw a lot of back in the day, when Blackstone was founded. Interestingly, magnesium is the dominant additive in this one, followed by zinc, phosphorus, copper, and boron (Figure 10). The flashpoint was lower than what we see today from 10W/40s.

Renuzit

At last, we finish our tour of ancient oils. (Some of these samples are older than the people reading this article. This makes me feel very old. Hey, get off my lawn!) I said before that I thought the Lucky Strike was the oldest of the oils we tested, but that’s only because I forgot about this can of Renuzit sitting in Blackstone’s garage. It’s rusty on the bottom so it leaks, and it’s not from a can like the others. This one was sold in a 5-quart metal jug. I particularly love this one, because the can not only says you’ll “Cut Your Oil Bills In Half,” but the first point of advertising on the side is a “Faster Getaway!” Now, they don’t actually say that this is the choice of oils for bank robbers, but I know if it was 1941 and my hungry Great Depression self was contemplating which oil to put in my Ford Special for bank-robbing time, this is the oil I’d pick. With practically no calcium or magnesium present, the oil’s TBN read 0.0, but it does provide would-be crooks with phosphorus, zinc, and barium as well as a 20W viscosity for the getaway (Figure 11). When you’re busy working a tommy gun, the last think you want to think about is whether or not you’ve made the right choice in oil.

So that’s the end of our series. A lot of thought goes into making oil, and that’s been the case for many decades now. We’ve poked some fun at the way oil companies sell their products, but heck, they’ve got to say something. We stand by our statement that “oil is oil” and in the end, it doesn’t make a lot of difference what you decide to use. Through all the years and all the permutations and configurations of oil and oil additives, the crude (and now, synthetic) stuff has kept cars running since Henry Ford did his thing more than 100 years ago. Buy what suits your vehicle and your wallet¾not what anyone else says you should use!

By Kristin Huff|2024-09-19T10:12:53-04:00July 20, 2023|Articles, Gas/Diesel Engine, Marine|Comments Off

The eBay Oils (Part 2)

Welcome back to the eBay oils! If you missed the first installment of this article, you can read it here.

True to his word, Ryan listened to his Passat (if you’ll recall, it was making a noise that sounded like “Sell Me” in German) and got his wife a new Hyundai Elantra this month. Free oil changes were not included as part of the deal, so Ryan will be changing his Elantra’s oil himself. And while he’s willing to experiment with his 1984 ½ ton Chevy pickup truck, it’s doubtful (for now, at least), that he’ll be using either Wolf’s Head or Fox Head oil in his new car.

Wolf’s Head SD 10W/40

Wolf’s Head Motor Oil Company was originally founded in Pennsylvania in 1879 as “Pennsylvania Crude.” (The source of this is Wikipedia, so take this information with a grain of salt.) I’d place the can from the late-1970s or early 1980s. It is “Formulated from Finest Quality Base Stocks and Superior Motor Oil Additives” and back then, like today, the container gives no actual clue as to what the additives are. That’s where we come in. The report is an interesting one. Note the lack of calcium, which is used in almost all engine oils nowadays as a detergent/dispersant additive. Instead of calcium, it contains a lot of copper as an additive. This is a trend we were glad to see die. All that copper in the oil masks bronze wear.

Wolf’s Head ATF

Wolf’s Head also made (makes?) an ATF, though the only selling point on this can is that it’s “Refinery Sealed.” Maybe they couldn’t think of anything interesting to say about it, because honestly it looks just like a lot of ATFs we see today: mostly phosphorus and zinc, with a smattering of other additives thrown in for good measure.

Fox Head 40W

Oil marketing has come a long way since the days of yore. Today when you want to buy a high-dollar oil you’ll find it has a name that conjures up something special: speed (Red Line), richness (Royal Purple), slickness (Amsoil), racing (Mobil 1), space-age (Quantum Blue), etc. I’m not sure what “Elf” is meant to conjure up, but they follow it up with “Excellium” so you know it’s Excellent oil. Contrast those names with our next contender, Fox Head, which just makes me think of…well, a fox head. In my oil. Fortunately, that’s not what analysis turned up. (Although…we don’t test specifically for fox heads, so we could be missing something here.) The Fox Head can is red, white, and blue, so you can feel patriotic when you buy it (unless you’re in Canada. Then you can indulge in justified rage about Americans and how we think we’re the center of the world). Fox Head oil was made by the Tritex Petroleum company out of Brooklyn, NY, and my extensive research (aka first-page Google results) tells me the company still exists and is presently located in Tulsa, Oklahoma. The logo, a sly-looking fox, has nothing on today’s slick oil packages. And the oil itself also has nothing on today’s oils: the oil itself is nearly bereft of additives. Basically a mineral oil, it has a little magnesium, phosphorus, and zinc in it, and not a lot else (Figure 3). This is not necessarily a problem, however. As you’ll recall in the article when Ryan used 30W aircraft oil in his truck, wear went up a little but the engine didn’t fail or anything. Still, I won’t be putting it in my Outback anytime soon.

Shell Rotella S 10W

Shell Rotella has been around for a long time. It’s good oil, and since they’ve been making it for decades, they’ve pretty much got the routine down and haven’t messed with it a lot over the years. Unlike now, when you can actually follow Shell Rotella on Twitter (who knew Rotella had so much to say?), back in the day Rotella had to get by just by on traditional advertising and word of mouth. We called Shell to see how long they’ve been making this oil and the guy not only could not tell me, but he was unable to tell me who might know. Surely someone at that company has a historical file? If so, they’re not sharing that info with plebeians like us. He did mention that Rotella really made its name in the ’70s, though I’m guessing this can of SF, SE, SC oil was made in the late ’80s. He also said the “S” versions of Rotella were sold internationally, and indeed, this can came from our friendly neighbors to the north (*waves hi to Canada). Suffice it to say that the oil has changed very little over the years. Its main additives are the same as what we see today, but the interesting part of this oil is that it’s a 10W (Figure 4). We often see heavy-duty thin-grade additive packages in tractor-hydraulic fluids, which are used in systems like transmissions and hydraulic systems in off-highway equipment like bulldozers and backhoes. Note the TBN of this oil read higher than most of the others we’re talking about. That’s because of the high calcium level¾the TBN is based on the level of calcium sulfinate and/or magnesium sulfinate. When those compounds aren’t present, you get a low TBN.

Quaker State 30W & 10W

Next up is another oil familiar to today’s buyers: Quaker State. This HDX oil is a straight 30W, and Quaker State was ahead of the marketing game on this one. The can’s copy touts their “high quality,” “modern refineries,” and “quality control laboratories,” and this was about as scientific as it got 30 or 40 years ago. The additive package is fairly stout, though like Wolf’s Head oil, calcium is in short supply (Figure 5). We also bought a can of Quaker State 10W oil, and when we looked at the report we had to go back and double-check the can to make sure this wasn’t actually ATF. It’s not: it’s labeled as an SAE 10W oil, though the additive package looks an awful lot like what we see of out today’s transmission oil. Interestingly, there’s a lot of barium in it (Figure 6). Barium must be expensive, or else it doesn’t do much, because we rarely see it in oil samples of any type nowadays. This is engine oil, but it might work in transmissions too.

Quaker State Deluxe 10W/40 & Sterling 10W/40

Apparently we are fans of Quaker State, because we also tested a couple more varieties: Quaker State Deluxe, and Quaker State Sterling. As you know, modern oil companies generally have a lot of different brands under the same name (for example, Valvoline has TK, TK, and TK, as well as TK). For the most part, these oils are mostly the same; they’ll throw in a few slight differences in additives and call it good. These cans of Quaker State, however, were mostly pretty different. The Deluxe version looked a lot like their 30W oil (but more calcium–Figure 7). Quaker State Sterling HD 10W/40, on the other hand, went out on a limb with almost 800 ppm sodium, almost no magnesium, and then levels of calcium, phosphorus, and zinc that are comparable with today’s oils. Touted as “Energy Saving Motor Oil,” Quaker State was getting its game on in pushing this brand: it mentions “special friction modifying additives,” the longevity of the company (over 60 years when the can was made), and its suitability for those wishing to follow extended drain intervals. Heck, I’m sold, and I see this stuff all the time.

Mobil Special 10W/30 & Artic 20-20W

Mobil is no slouch in the marketing department, but they really outdid themselves with the can we tested, “Mobil Special.” The name alone tells you all you need to know about why to buy this oil. All oil companies like to mess with their additive packages, and Mobil, like the others, changes their oil up fairly frequently. That was the case back in the day too, because the additive package in this “Special” oil is different from what we typically see in today’s oil. Apparently Mobil was an early rider on the ZDDP train, because this oil is chock-full of both phosphorus and zinc. Calcium and magnesium are present too, but at lower levels (Figure 8). We also tested a sample of Mobil Artic oil. The Artic can is clearly older than the other Mobil can¾the logo is older, and there’s no zip code listed with the address, so it’s pre-1963. A straight 20W, it’s labeled as HD oil, meeting “Car Builders’ Most Severe Service Tests.” While it’s “Artic” and not “Arctic,” we can’t help thinking this oil is meant for cold-weather operation. The can even looks like it’s ready for winter: all white, but with a little color on it so you don’t lose it in the snow when you’re out in the tundra changing your oil. This one definitely has an unusual additive package, relying heavily on barium (maybe it’s got a purpose after all!). Interestingly, less zinc is present than phosphorus (Figure 9). Nowadays it’s the other way around.

Phillips 66 Trop-Artic 10W/40

We were going to stop with Mobil Artic, but we can’t resist comparing that one with Phillips Trop-Artic. We’re not exactly sure what Trop-Artic means, but since the can is selling itself as All-Season we’re guessing it’s something along the lines of “use it in the tropics, use it in the arctic.” A 10W/40 in viscosity, this oil looks a lot like what we see out of modern 15W/40s¾a stout additive package and a relatively thick viscosity (Figure 10). In other words, even though this oil is several decades old, it would be fine to use in your F150 tomorrow.

Okay, ten old oils is all we can do for this article. Fortunately the next installment will contain such gems as old versions of Amsoil, Castro, Sinclair, Amoco, Lucky Strike, Union 76, and more! Tune in next time for the next installment of the eBay oils!

By Ryan Stark|2026-01-19T14:26:31-05:00July 20, 2023|Articles, Gas/Diesel Engine, Marine|Comments Off

The eBay Oils (Part 1)

We were visiting my in–laws last November and needed some oil for my Passat. It just starting to clatter a little on start up and when I checked the oil, it was down two quarts. The clatter sounded something like “Sell Me” in German.

Anyway, while searching for some make up oil (my father-in-law Lee had two quarts of my favorite—Super Tech), I came across an old can of Pennzoil ATF. By old I mean it was a round can made of cardboard, like a Crisco can. It brought back memories of helping my Dad change oil when I was seven or eight. (My job was jabbing the pour spout into the top of the can.)

Lee said he bought it for an old 1984 Buick LeSabre. That was the last car he owned that leaked oil and when that car was gone, he was left with half a can of ATF. Working in an oil lab, I was intrigued by what was in it. So Lee let me have the quart because he would never need it again.

When I got back home, I started looking at old cans of oil on eBay and found a lot. It turns out these are fairly collectable, and I found roughly 300 unopened cans for sale, of all different types and years. I decided that in the interest of science, Blackstone should buy some of these and test them to see what was in them.

Now, you may think I’m crazy because once you open an old can of oil like that you ruin the value of it, but I was prepared to make this sacrifice for the good of the oil analysis community, and plus, Blackstone was buying, so it really didn’t bother me too much. If you think about it, how lucky can you get to be able to buy little time capsules of a product and test it? Can you by beer from 30 years ago and still drink it? I guess, but chances are it’s long gone bad. How about a 30-year-old can of sardines, or a 5-year-old one for that matter? No way. So, I would really be a fool not to try this and see what shows up.

One thing led to another and before I knew it I had bought 28 cans of old oil and spent almost $1,000. Pretty soon these oils started rolling in and I experienced a little buyers remorse. Did I really need to buy all this? What was I going to do with the cans? Once you open a can of oil, it’s almost impossible to seal up properly. Would there be anything to even see in these samples? And, does oil go bad? We get this last question all the time, and my answer has always been no, but I was dealing with oils from the 1930s,1940s, and 1950s here–really old stuff. Maybe all the additive in there (if any was even used) would settle out and there wouldn’t be anything for us to read. Fortunately, I had bought some oil that would help answer that.

Shaken, not stirred

Before I did any testing, I wanted to see if I would need to shake these oils up. If the additive had fallen out of suspension, then all of these old cans would need to be shaken before I even opened them. Ideally, it would be great to have two oils of the same batch, so I could run one unshaken and run one shaken and see what type of difference shows up. That’s where my two antique vintage Havoline Texaco all-metal cans came into play. “SAE 20-20W” is stamped on the top of the can, and the text on the back says, “For API engine service classifications MM, MS, DG, and DM.” It also assured me that it’s “The finest engine protection in the world.”

I bought these two for $25.00 total, and going by what looks like a date on the can, I think they were from 1968. They were from the same seller and looked exactly the same. Chances are good they came from the same case someone bought years ago and they have been sitting on the shelf even since.

I decided to run a test. I would take one to the local hardware store (www.doitbest.com) and have them put it in the paint shaker for five minutes. Then I would crack them both open, test them, and see what differences showed up. You can see the results in Hav No Shake and Hav Shake.

To my surprise, there was actually more of some additive in the oil that I didn’t have shaken. Also, the additives really weren’t that different from what we see in today’s oil. The oil was supposed to be a straight 20W and it was. Also, it had a strong TBN, so the additive that was present was still active.

About the only unusual thing was that phosphorus was higher than zinc. Those two elements are normally from the ZDDP additive, but maybe there were using a different formula back in 1968. It’s hard to say, but from that test I learned that when it’s done right, the additives actually become part of the oil during blending and time/gravity alone won’t cause them to separate back out.

So that settled it. I didn’t need to shake all of these oils and could just start running them. That’s good because some of these old cans were bound to break open during shaking and spray oil all over Norm and his paint department.

But is it still good?

However, that really didn’t get down to answering the question: Is this oil still good to use? For that, I was going to have to run another test.

Of all the oils I bought, one of the most expensive was very rare—according to the seller, antique Renuzit Certified, Premium Quality 2500 Mile oil. Not only does this oil offer the ability to run the oil 2500 miles in between oil changes (“Cut your oil bills in half!”), but it claims to provide a longer engine life, smoother motor, stronger oil film, and best of all, “a faster getaway.” They don’t actually advertise it as the best oil for bank robbers, but they should have.

It cost $75.00 + $25.00 shipping, but I got a whole gallon of it. Unfortunately, the can had some rust on the bottom of it and it started leaking during shipping. The good news was, I now needed to do something with this oil and I wasn’t going to dump it in a waste barrel. So I am going to actually run this in my engine. Not in my Mini (it’s still under warranty), but my trusty old GM 350, rebuilt twice by yours truly.

I know what you are thinking—this SOB is out of his mind!—but don’t try to talk me out of it. I’m going to run this oil and decide once and for all if running old oil really hurts anything. Will my engine blow-by and leave me stranded on the side of the road? Will the seals start leaking like mad a leave a slick of oil behind for other cars to slip on and spin off into the ditch (a la Spy Hunter)? Will this be the end of my beloved 1984 Chevy Custom Deluxe? Well, like the monkey said after he shit in the corner—that remains to be seen!*

Castrol with Tungsten

My first purchase was Castrol with Tungsten. Tungsten! What the hell? Since when did they start putting light bulb filaments in oil? Or maybe a better question would be, “When did they stop?” The bottle was partly in French, so I’m guessing it was from Canada, and that makes sense; the oil blenders up there will put anything in the oil and if the engine breaks, they just blame it on the cold. (Just kidding, Canadians! You know we love you guys.) I had to buy the single element standard to run Tungsten and set our spectrometer to run it, but after a little messing around, we got some results .

Sunoco DX Diamond motor oil – API SB

After seeing Castrol with Tungsten, I was ready for anything, but when I saw Sunoco’s Diamond oil, I didn’t really think they put diamonds in there. That would be one expensive additive. I did want to see what was in this SAE 40W oil though.

The case says is has an API rating of SB, which was used from 1930 to 1963. Several websites state that this oil can cause equipment harm. All I can say to that is, too bad I don’t have five quarts of this stuff, because I love a challenge. It doesn’t look so harmful in the oil analysis. The viscosity wasn’t quite in the 40W range and it didn’t have much in the way of detergent/dispersant additive present, but then again, it does state on the can that it is “Recommended for vehicles that do not require detergent oil.” Sometimes those oils don’t have any additive at all, but there was quite a bit of phosphorus and zinc here (figure 4).

K-Mart 10W/40 Motor Oil (API SE) & DEXRON ATF

Back before Wal-Mart dominated the world, there was K-mart, and when I was in 4^th grade, there was no greater crack on someone than “You buy your underwear at K-Mart.”

Well, I wonder what those boys would say if they found out I bought my oil at K-Mart too. The motor oil is listed as Deluxe and it says on the side of the can that this is specially blended multi-viscosity oil containing the finest approved additives and base oils. So you can’t go wrong there, right?

Looking at the results, I’d say this oil is indeed deluxe. The viscosity is pretty strong for a 10W/40, and the additives would be suitable for diesel use. The oil does have a CC rating as well as an SE rating, and those put the date of this oil as being made sometime in the 1970s. The ATF has a standard additive package until you get down to barium. That’s not used much anymore. See figures 5 and 6 for the analyses.

Valvoline SAE 20W – API SB

The big marketing claim for this oil says it “Contains Miracle ChemAloy.” Miracle! Really! Does the Pope know about this? There were no miracles in the additive package that I can see, but maybe that’s the miracle of it—you can’t see it, but it’s in there and it works. This oil doesn’t have much of a TBN because it doesn’t contain much calcium, but the old stand-bys of phosphorus and zinc are there, and at pretty much the same levels we see today (figure 7).

Harley-Davidson Premium Grade Motorcycle Oil (SAE 40) 75-P

This can caught my eye because it reminded me of Evel Knievel. In fact, the logo on the can is the same as what is on Evel’s website, so the two were heavily linked back in 1970s.

What’s interesting is that Harley-Davidson actually came up with their own oil weight specifications. This can is 75 Medium Heavy and is for use in all motors at temperatures above 40°F. They also made 58 Special Light, which is good for temperatures below 40°F, and 105 Regular Heavy—good for all motors operating under severe conditions at high (?) temperatures. Apparently, it was up to us to decide what high temperatures are; also, neither the 75 or 105 was “special.” I’m sure the special label added some extra cost and that made it special to Harley-Davidson.

Looking at the report, you’ll see this was a 40W oil and WOW look at the barium. That isn’t used much anymore and was likely some sort of detergent additive (figure 8).

ARCO Graphite SAE 10W/40 (API SE-CC)

After seeing the word graphite in the name, I had to check this stuff out. True to its label, there was a lot of graphite in the oil (figure 9), and if you’re the kind of person who likes clean oil on your dipstick, this wasn’t the brand for you. Graphite is known as a lubricant, but I wonder how this stuff did in engines. Looking at the report, you can see the graphite at the insoluble reading of 0.5%. That’s extremely high for virgin oil, so the stuff doesn’t stay in suspension very well. On the plus side, the can says this oil provides

Improved gasoline mileage
Reduced piston ring and cam wear
Easy low temperature starting and excellent lubrication at low and high operating temperatures

The oil is also “Patent Pending” and I’m wondering how that application is progressing down at the Patent office these days.

In Parts 2 and 3 of “The eBay Oils” we’ll be looking at old cans of Amsoil, Mobil, Valvoline, and more. Look for the next installments this summer!

By Ryan Stark|2026-01-19T14:26:49-05:00July 19, 2023|Articles, Gas/Diesel Engine, Marine|Comments Off

Ryan’s Cholesterol

A few years ago I went to our family doctor for a checkup. For most of my life I’d never been one for getting check-ups, but now my insurance company pays for a yearly visit, so I decided to start.

After all the basics, the doctor suggested I do a blood test, because I’m “getting old” (almost 40!?). So after fasting for 24 hours to make sure nothing I ate would skew the results, I headed to their lab to get my blood drawn.

You can imagine my dismay when the nurse called a few days later with my test results — high cholesterol! My initial reaction was shock, followed by a realization that maybe I am indeed getting older.

The nurse said my total cholesterol read 203 and that the doctor wanted me to change my diet and start taking the drug Lipitor. Again, more shock followed by a little confusion as to what exactly 203 meant, and then a wave of depression at the idea of having to take a drug for the rest of my life, along with quitting eggs, butter, and bacon. “Fortunately,” the nurse continued, they offer free Lipitor at the local supermarket pharmacy, like that was supposed to make everything all better.

After a few letting this all sink in, I decided that I was not indeed getting older. In fact, I’d wager that I was the healthiest SOB my doctor had seen all month (based on the state of the patients in her waiting room).

Looking at data

Also, given the fact that I look at data all day long, I began to wonder about the 203 reading. What’s average, what are the units on that, and what was my average cholesterol reading? Maybe I’ve always read high.

After a little more thought, I decided to just ignore my doctor and get retested to see if I can get a trend going. My thinking was, maybe high cholesterol is kind of like high iron in your oil. We normally say that just one high reading isn’t much of a concern. Maybe it was higher before but it’s headed down now, or maybe this level is just normal for you and the way you operate your engine. A trend gives you far more information that just one bad reading. We usually wouldn’t suggest any major changes after one just one high reading, so I was a little disheartened that my doctor would prescribe a lot of life-changing measures based on one test. My course of action would be to get more information about it and check back to see if the high reading was a one-time occurrence or not.

So I had my blood tested again about a month later to see if the first test was accurate. Unfortunately it was, but still, that made me feel a little better about the repeatability of the lab and that test itself.

The vitamin D cure

As luck would have it, that same month I attended a lab training session in Columbus, Ohio at Mettler Toledo (they make an awesome auto-titrator if you’re even in need).

During dinner one night with the other class attendees, we got to talking about Vitamin D and its relationship to cholesterol. My classmate was in the business of testing for Vitamin D levels in food and said that there is a direct relationship between the two. As it turns out, the more Vitamin D you get, the lower your cholesterol goes. And what’s more, Vitamin D is free to us all, being produced naturally by your skin when it’s exposed to sunlight.

This really got me thinking — my first and second blood tests were taken in during the high of winter in the Midwest. A person doesn’t get much sunlight in the winter (at least in Indiana). So maybe if I checked my cholesterol again in summer, it would improve. This started me on a quest to get my blood tested again that summer to see if I could indeed confirm that there was a relationship between Vitamin D and cholesterol.

At the start of September, I called my doctor and requested another blood test, and this time I wanted Vitamin D added as well. After a few days the nurse called with my results. It turns out my Vitamin D level was low at 30, and she wanted me to start taking a supplement to see if I can bring that up (again with the knee-jerk reaction to one reading).

“How about my total cholesterol?” I asked. “Oh, that’s fine at 156.” she stated. This was an eye-opening test because it proved that my cholesterol level did indeed change significantly and I didn’t have to change my diet or take any drugs to artificially lower it.

This also brought up a mildly chilling realization. Suppose I started taking a drug to lower my cholesterol back in February and then had it tested again in September. My cholesterol would have read lower, but everyone would have pointed to the drug as the reason and I’d be stuck taking it for life.

After-market oil additives are a parallel to this in the oil analysis world. A lot of people start to use an additive and after several years start to think it’s the reason their engine is running well. When in reality, chances are very good the engine would still be running fine had they not used the additive.

Trends are key

All of this started back in 2013 and I have accumulated a lot of data since then on my cholesterol and Vitamin D levels. Being in the lab business, I wanted more data before I made any hard and fast statements and I’m still not ready to say one way or the other that the Vitamin D and cholesterol are related. I’m not advocating that you ignore your doctor’s advice (that’s a Stark family virtue), but I am saying that as far as testing goes, it’s not very often that you need to take action just on one bad reading. Trends are important when analyzing data, so be sure to get them even if it takes a little pain.

By the way, during all of this blood testing, I found myself longing for a lab where you could walk in and easily get blood work done without a doctor’s order, one that would send you your results in a nice, easy-to-read format, with an explanation of the data in plain English.

Also, the report would show you an average so you could get an idea about how high or low a reading might be. Whoever could come up with this type of medical lab in real life would be sitting on a gold mine. Now, you may ask, “Why don’t you start one, Blackstone?” and the answer to that is easy—we’re too busy testing your oil.

_______________________

Cholesterol follow-up

Back in August 2015 I wrote about cholesterol testing and its parallels to oil analysis. I’m sure you’re all wondering how my health has been, so this is a follow up to that. In the article I stated that there appears to be a connection between Vitamin D and cholesterol and I am here to tell you that I might have been wrong.

My final blood test was on August 7, 2015 and at the time I was taking a Vitamin D supplement to see if it would lower my cholesterol. Well, the supplement worked: my Vitamin D increased to 33, which was an all-time high; however my cholesterol also increased. So barring any sort of lab error that might have occurred, I’m not sure if there is a conclusion or not.

That article received a lot of feedback and I enjoyed all of the comments from our customers, but was especially intrigued by one e-mail I received. He pointed me towards the book “The Great Cholesterol Con,” by Malcolm Kendrick, and while it wasn’t the easiest read I’ve ever come across, it did change my life.

The books states that cholesterol levels aren’t related to heart disease at all and that I should eat anything I like. Well, I’m 43 now and can make up my mind on what I do, and I have to say, I really liked the sound of that. It was the first time I had ever heard anyone say that your diet isn’t related to heart disease and he had that data in his book to back it up.

I’ll admit I never read any of the studies he talked about, though apparently they are all available on the Internet. As for what causes heart disease, well, I won’t spoil the book for you ¾ ha ha just kidding, I’ll spoil it: stress! Reduce that in your life and you’ll be better off. Who can argue with that? Plus now that I don’t have to feel bad about putting butter on my toast, my life just got less stressful.

_______________________

Yet another follow-up

A few years ago I wrote an article about how trends in blood tests were just as important as trends in oil analysis. This medical talk spurred a lot of comments and advice which I greatly appreciate, though surprisingly enough, not too many of you seemed concerned about my suicidal-scorn for statin drugs. Still, I’d like to thank all of those was responded and I’d like to pass on one bit of great advice from a doctor/pilot. His best advice for living a long healthy life: Stay off ladders.

By Ryan Stark|2024-09-19T10:15:06-04:00July 19, 2023|Articles, Gas/Diesel Engine, Marine|Comments Off

Blackstone and the Post Office

(TL;DR: You can use the labels that are on your kits now, but if you’d like new ones, you can print one here.)

“I am FED UP,” said the customer on the phone. “Do you even have my sample? I mailed it a month ago.” I looked up his tracking number and he wasn’t exaggerating – he mailed it September 15, and we had just received it that day, October 15. Sound familiar?

Why is it taking so long for samples to arrive? And what are we doing about it? Read on, Blackstone fans. Have we got a story for you.

The Post Office makes some changes

“I think the post office isn’t charging us enough.” Ryan Stark, Blackstone’s president, and my brother and business partner, said to me one day last November after reconciling the checkbook. He’d noticed that for the last few months, the amount we were paying in postage had dropped significantly.

Stick with me, this is all going to tie together.

Last summer, just as we were all realizing the pandemic was not simply going to disappear, I learned the post office was ending their Merchandise Returns program. Because our samples came back to us on MR labels, we needed to create a new one, so I had my printer start working on it.

A major part of that process is getting approval from the USPS at various points along the way. And that’s where the process slowed…then slowed down some more…and then, like molasses on a winter sidewalk, came to a creeping halt.

We called USPS. How’s the label going? No reply. We emailed. How’s the label coming along? Nothing. Time passes. Months go by. Sometimes we’d get a reply – “We should have an answer for you soon!” But then…nada.

Back to the money

Meanwhile, the issue of not paying enough postage was still a problem. What do you do when you think the USPS isn’t charging your business enough? You call them – so I did.

I first contacted my local post office – the ones who deliver us samples every day, the ones who know who we are and what we do. “I think we’re not being charged enough,” I explained. “Nope, that’s not me,” she said. “They take care of that in Indianapolis now.” She gave me a number, so I called down to Indy. “Huh,” the Indy person said. “Let me look into it.”

Reader, you can see where this is going.

I got nowhere in November, so I called again in January. “Hey!” I said. “I still don’t think we’re getting charged enough!” “Hmmm” said the voice on the line. “Let me ask my supervisor about that.”

Time marches on. After calling and emailing various USPS representatives throughout February and March, I got fed up in April and sent an email blast to every single USPS contact I had, including the ones in Washington, D.C.

That one got some attention.

They started looking into what was going on, and to make a long story short, the issue culminated in a conference call with several USPS bigwigs. “Well,” said Bigwig #1, “you owe us (insert a huge amount of postage here. Nope, it was more than that).

It turns out that when the USPS stopped their Merchandise Returns program, our local post office stopped charging us for our incoming samples. We were still being charged for outgoing mail, but we hadn’t paid postage on incoming samples since the MR program ended in August.

After much gnashing of teeth and some heated words on my end (would they ever have caught the problem if I hadn’t kept after them? We’ll never know), we settled on a plan to pay the outstanding postage.

As part of this reconciliation, one of the USPS Bigwigs suggested we have samples returned to us in a Tyvek envelope, to help catch spills. Well, oil spills aren’t really the problem with getting samples delivered, but I tucked the idea away for the future.

Back to the labels

Meanwhile, the new label still had not been approved. And people still needed kits. While all this was going on, we continued to print and send out hundreds of thousands of old labels on kits. What choice did we have? Now those old Merchandise Return labels are now on kits that are sitting in garages, hangars, and marinas all over the country.

So when did we get it resolved? We officially started printing our new, USPS-approved labels more than a year after the old label was officially discontinued. The thing is, the post office reassured me that it would be fine to continue to use our old label – we would just have to pay more when people returned them.

Which is fine. Fine, fine, fine. Except, for some post offices, it’s not so fine. Most of those old, Merchandise Return-labeled kits get here no problem. But occasionally, a post office will hold on to it and not deliver it because it’s the old label, even though they said we could keep using them.

At this point, there’s nothing we can do about the thousands of old labels that are in circulation except try and get the word out. So that’s why you’re reading this. If you have old labels on your kits (they say Merchandise Return right on them), click here to ask for new ones. We really do want to receive your samples. And we don’t want you to have to wait for a month to get your results.

But wait, there’s more!

So while all of that was going on, Travis – a long-time Senior Analyst-turned-coder – had an idea. “What if,” he said to me one day, “we do a test to see if putting samples in a Tyvek envelope helps with the return postage time?” Because although oil spills aren’t a significant problem, it does seem to be a problem that the mailer is 1) small, and 2) clearly headed for a laboratory. Putting the oil into a Tyvek envelope might solve both issues. So we started a test – for one month, we sent all outgoing kits with a labeled Tyvek envelope for returning the sample to Blackstone.

The results were immediate and striking: this was a winner. We didn’t even run the test for the full month. The data Travis put together showed that return times were cut in HALF (from an average of 8.74 to 3.48 days) when samples came back to us in the Tyvek envelope. (See the sidebar.) We stopped the test and immediately started including Tyvek envelopes with each kit order, for return samples.

USPS supporters

Despite the problems, we are proud supporters of the United States Postal Service. No other carrier offers service to every single part of the US, no matter how remote. Lots of people don’t have access to UPS or FedEx, though if you want to use them to send in your samples, that’s absolutely fine.

The changes we’ve made to our label and the return package are already paying off in getting samples to us in a timely fashion. If you need new return envelopes and labels for your kits, let us know – we’re happy to send them out!

______________________________________

Update! The Post office has discontinued their First Class Return labels (my new mantra: change is good…change is good). We are now using Ground Advantage labels. All the same things in this article still apply. You can use the First Class return labels, but your sample will arrive faster with a Ground Advantage label. You can print one off right here.

By Kristin Huff|2024-09-19T10:15:59-04:00July 19, 2023|Aircraft, Articles, Gas/Diesel Engine, Industrial, Marine|Comments Off

Protecting from Corrosion

Considering the relative inactivity of much of the general aviation fleet, it’s not surprising that corrosion is a hot topic. It’s also fodder for aviation oil makers to claim their oil is better than others at protecting engine parts from corrosion.

The frustrating thing when you can’t find the time to go flying is, your beautiful bird is languishing alone in a dark hangar accumulating rust on its parts and dust and bird doo on its wings. What to do?

If you can’t fly it, you don’t want to just ground-run the engine since it’s pretty well accepted that doing so may cause more harm than good. In the end, the path most often chosen is to “leave her sit.” But that’s the maddening part. You just know that corrosion has begun at the cylinders, cam, and lifters, as well as all the other parts that are parked above the engine’s oil level. “Dammit! Maybe I should go out and shoot some landings.” But you don’t. So the question still stands…what to do?

We get a lot of questions about which oil protects aircraft engines best from corrosion. If there were a sure answer as to which oil is best, someone would surely have come up with it. Since they haven’t, perhaps we should reconsider the question. Maybe what we should be asking is, “What can I do to prevent corrosion in my (not flown frequently enough) aircraft engine, regardless of the oil I use?”

Turned around that way, there may be an answer.

Water orbs

Oil and water don’t mix at the atomic level. Since there is no such thing as dry oil — both hot and cold oil suck moisture from the air like a sponge — the only way these dissimilar types of matter can coexist is for the moisture to ball itself up into minute spheres, so tiny that they can exist in suspension. If the water orbs get large enough they will precipitate, that is, fall out of suspension. But there is almost no limit to how tiny they can be. The longer the oil sits undisturbed, the more water it will accumulate.

Oil routinely has some moisture in it, usually at levels between 40–400 ppm. In amounts greater than that, it can start to make your oil look like chicken gravy. Once moisture sets in, heat and/or pressure are the only way to get it out. If you go out and fly for an hour, the oil temperature and agitation will dismiss the moisture droplets like unruly elementary students. The moisture accumulation process will start all over again once you pull idle cut-off, but at least you have the satisfaction of knowing that, at least for now, the fine film of oil clinging to the metal parts is not heavily populated with tiny balls of water.

Fighting corrosion

After you lock the hangar door, the dry (well, reasonably so) oil film doesn’t last long on all those parts that are parked about the oil level. If your engine is a dry-sump type, none of the parts are parked in an oil bath.

If you can’t fly, you might consider using a pre-oiler once a week to rebathe all the parts in oil. The oil from the pre-oiler will reach all parts that see oil pressure during engine operation. It would require only turning on the master and the oiler switch for a short while, no longer than it takes to check the lights and flaps during a preflight, a few minutes at most. The oil should reach all the way up into the rocker boxes and then drain to form a brief pool over the tappets and cam, parts that are notoriously prone to corrosion pitting in all but the most active engines.

After the pre-oiling dose, you could get out and pull the prop through a few blades (normal direction of rotation, of course) to ensure all moving parts rotate through a couple of full cycles. Further, you will be giving all the rod bearings an oily trip through the sump reservoir, for wet sump engines. (Some people are queasy about touching the prop, so running the starter is an acceptable alternative, if you have confidence in the integrity of the battery.)

Cold dousing all oil-wetted parts isn’t nearly as good as an hour’s flight, but it seems far superior to the ground run-up, or the more often chosen “letting her sit.”

By Jim Stark|2024-09-18T13:48:37-04:00July 18, 2023|Aircraft, Articles|Comments Off

Pre-Ignition and Detonation

The information (and harrowing pictures!) that follows is reprinted courtesy of the FAA.

Pre-ignition. Detonation. Both can be deadly. But what’s the difference? And how can you avoid them?

This engine is from a Beech S35 Bonanza’s fatal accident. The #6 piston was eroded and began to melt. The rings and piston skirt were compromised by thermal expansion and metal transfer. Note the deep pitting and erosion of the piston face. This caused combustion gases to bleed into and over-pressurized the crankcase, forcing engine oil out the breather. The connecting rods then failed due to the lack of lubrication and smashed holes in the crank case, causing loss of power and engine failure.

Normal combustion vs. pre-ignition

Normal combustion is an orderly, progressive burning of the fuel-air mixture in the cylinders. The gasses within the cylinders are ignited from the top. The flame then travels down in an organized way. This combustive force, equally applied to the piston in a stable manner, pushes the piston down. The downward motion of the piston is then mechanically transferred to the propeller. This makes pilots very happy.

In a pre-ignition event, combustion is abnormal. It happens when the air-fuel mix ignites before the spark plug fires, while the piston is still moving up in the compression cycle. The ignition can be caused by a cracked spark plug tip, carbon or lead deposits in the combustion chamber, a burned exhaust valve, an ignition system fault, or anything that can act as a glow plug to ignite the charge prematurely.

When this happens the engine works against itself. The piston compresses and at the same time the hot gas expands. This puts tremendous mechanical stress on the engine and transfers a great deal of heat into the aluminum piston face damaging the piston. Engine failure can happen in minutes.

Detonation

As the name suggests, detonation is an explosion of the fuel-air mixture inside the cylinder. It occurs after the compression stroke near or after top dead center. During detonation, the fuel/air charge (or pockets within the charge) explodes rather than burning smoothly. Because of this explosion, the charge exerts a much higher force on the piston and cylinder, leading to increased noise, vibration, and excessive cylinder head temperatures.

The violence of detonation also causes a reduction in power. Mild detonation may increase engine wear, though some engines can operate with mild detonation. However, severe detonation can cause engine failure in minutes. Because of the noise that it makes, detonation is called “engine knock” or “pinging” in cars.

High heat is detrimental to piston engine operation. Its cumulative effects can lead to piston, ring, and cylinder head failure and place thermal stress on other operating components. Excessive cylinder head temperatures can lead to detonation, which in turn can cause catastrophic engine failure. Turbocharged engines are especially heat sensitive.

Some causes of detonation include:

improper ignition timing
high inlet air temperature
engine overheating
oil in the combustion chamber
carbon build-up in the combustion chamber

A combination of high manifold pressure and low rpm creates a very high engine load, which can also cause detonation. In order to avoid these situations:

When increasing power, increase the rpm first and then the manifold pressure
When decreasing power, decrease the manifold pressure first and then decrease the rpm

Pre-ignition and detonation results

The explosion of pre-ignition and detonation is like hitting the piston with a sledge hammer. The automotive term for the sound it makes is “ping” (something pilots cannot hear in aircraft). The ping sound is the entire engine resonating at 6400 hertz. It sounds like a ping, but it is an explosion with enough power to make the engine resound like a gong.

Both pre-ignition and detonation put tremendous mechanical stress on the engine and transfer a great deal of heat into the piston deck. This can cause the piston to melt (EGT is 1600 degrees; aluminum pistons melt at 1200 degrees). The force of these explosions can knock holes in pistons, bend connecting rods, overcome the lubrication film in the rod bearings, and hammer the babbitt out of rod bearings. Engine failure can happen in minutes.

The bent connecting rod at the start of the article is a good example of the damage pre-ignition and detonation can do.

These cylinder #2 spark plugs are packed with melted piston material.

Here’s what happens

This is a cylinder head showing signs of pre-ignition or detonation.

The carbon coating that normally lines the head dome is knocked off. There is melted piston material in the head and the cylinder sleeve is scored by the overheated piston.

This is the same piston , but note that the piston deck is eroded.

The rings are broken. The piston skirt is scuffed from rubbing on the cylinder wall. A piston in this condition allows combustion gases into the crank case. This over-pressurizes the crankcase and blows engine oil out of the crank case breather — all of the engine oil, in minutes.

Soon after the engine oil departs the connecting rods try to make a break for it, resulting in giant holes in the crank case.

How do I detect pre-ignition?

A rough-running engine can be the first sign of pre-ignition or detonation. High EGTs or CHTs can be a sign of a problem so be sure to keep an eye on that if you can.

Below are common indications of detonation. You should have increasing oil temperature, not pressure. The top left gauge is RPM. The top right is manifold pressure.

What do I do when it happens?

Since excessive heat can be so damaging, your main priority is to cool the engine:

Reduce power
Increase airspeed
Enrich the fuel mix
Open the cowl flaps.
Land immediately!

Preventing Pre-ignition

Do not take off unless the run-up is perfect
Maintain the ignition system
Pay attention to cylinder compression tests
Use the proper heat range spark plugs
Make sure cooling baffles are in good repair

Preventing Detonation

Lean the engine per the flight manual
Keep engine load to a minimum
Do not over boost
Use only the recommended fuel grade
Make sure engine timing is properly set
Make sure cooling baffles are in good repair
Be wary on hot, dry days
If in doubt, run rich

By Kristin Huff|2024-09-18T13:48:58-04:00July 18, 2023|Aircraft, Articles|Comments Off

Aircraft Problems: Should I Be Worried?

One of the main purposes of oil analysis it to find problems that might be developing in an engine, and after doing this for a lot of years, I can say without a doubt that it works. However, some problems are more urgent than others, and part of our job is to determine if a problem is a major one or not. Most engine problems start out minor but if left unchecked can lead to major issues, which eventually result in an engine’s demise.

Minor problems

Abrasive Contamination

Dirt getting past the air filter will cause a lot of problems in an engine, and piston scuffing is the primary concern. Fortunately, most air filters do a really good job even when they are dirty. If you change your air filter on a regular basis, then this type of problem is pretty easy to avoid, but remember, it’s also important to check the whole air induction system down-stream of the air filter to make sure no cracks or other problems exist that could be letting dirt in.

Fuel dilution

This generally includes any fuel level between 1.0% and 3.0% that keeps showing up again and again. This is not a normal situation, but it doesn’t necessarily cause an engine problems in the short term. Still, since fuel is a contaminant, it will cause the oil to oxidize faster that it normally would. That typically causes problems like stuck oil control rings, which leads us to our next minor issue.

Oil Consumption

This one isn’t really a problem at low levels because all engines are designed to use some oil. What you really want to watch out for is a change in how much oil is being burned. If you always use 1 quart every 10 hours and it suddenly jumps to 1 quart every 3 hours, then you know something has changed. That’s part of the reason we ask about oil added between changes. If you’re not losing oil due to a leak, it’s either getting past the rings or the valve guides. Granted, you can buy a lot of make-up oil for the cost of a top overhaul, but there will probably come a time you’ll have to bite the bullet and fix the issue.

Corrosion

If you fly around 5 hours per month, that should keep this minor problem off you mind, though we all know that life doesn’t necessarily allow this. Still, if corrosion is minor it should easily disappear once the engine is back to flying regularly. If corrosion gets so bad that it causes pitting on the parts, that’s when the problem elevates to major status.

Major problems

Cam spalling

This one is often directly related to corrosion getting out of hand, though it can also be related to oil starvation on things like cold starts and high RMP starts. It takes time for that thick oil to get circulating through the engine and if it doesn’t get to the cam and followers fast enough, metal-to-metal contact happens. Problems of this nature won’t necessarily cause an engine to fail, but can lead to loss of some power, which might be needed to clear that 50’ obstacle at the end of the runway.

Excess Heat

This is really a pretty broad category and is often due to operational factors, though it’s almost always avoidable if you are paying attention to your cylinder head temperatures. If those are getting too hot, then maybe the cooling baffles aren’t quite working like they should. Maybe you have a crack in an air induction tube. That could allow abrasive dirt into the combustion chamber, but would also cause that one cylinder to run leaner than others (due to extra air being sucked in) and likely hotter. Excess heat causes the parts to expand more than they were designed for and that’s when wear starts getting heavy.

Stuck or Burned Valves

Abrasive contamination, fuel dilution, and oil consumption will all contribute to this type of problem. Sticking valves can be identified by things like morning sickness (not necessarily in the morning), intermittent rough running, and high mag drops (not due to a fouled spark plug). Burned valves are usually pretty easy to spot with a borescope though might not necessarily cause major operational problems until they burn to a point where compression has significantly degraded.

Detonation

This issue develops in an engine when the combustion process is not completed correctly, usually when an engine is under a heavy load and producing a lot of heat. It can easily burn a hole right through the top of a piston, resulting in all of the oil in your engine being pushed out the breather tube and oil starvation (see below). If your engine had a good muffler, you would hear a ticking or pinging noise, but since those don’t exist in general aviation, this problem can often go unnoticed without the help of oil analysis and/or engine monitor data. If this problem exists, running a richer fuel/air mixture to keep the engine cooler should help.

Instant failure

Oil starvation

Whether it’s caused by oil consumption left unchecked or severely worn bearings not letting oil get to all of the parts, this type of problem will cause an engine to fail in short order and it’s usually accompanied by the worst sound your engine can make — silence.

Spun bearings

When the babbit is worn off your bearings, either due to hard use, abrasive oil, or lack of oil, you will start to lose oil pressure. If the problem gets severe enough, the spinning shaft will actually weld to the bearing itself and spin in place. Once this happens, the engine is pretty much shot, though amazingly enough it might still run (but not for long).

Outside causes

Of course there are lots of other things that can cause instant engine death — see the first cartoon on this link for an example, or, although it’s not a plane, this picture of my flooded MINI. Unfortunately, outside factors probably take more engines down than anything else.

It’s pretty rare for engines to fail suddenly due to minor issues, so when we see something going on, that doesn’t necessarily mean you need to get out the wrenches or head straight to the engine builder and demand a repair. Usually, you’ll have some time to see if the problem persists or is getting worse. Once that has been established, then some action will likely be required to keep the engine going, but the cost should be minor compared to the hassle and expense of having to replace the whole engine. So test your oil every now and then. Chances are good your engine will look perfect, but if it doesn’t, you’re better off knowing about it sooner rather than later.

By Ryan Stark|2026-01-19T14:27:01-05:00July 18, 2023|Aircraft, Articles|Comments Off