40 Years of Testing Aircraft Oils

This summer marks our 40th year in business, so we thought it would be interesting to have a look back at our history in the field of aircraft oil analysis and how we got to where we are now.
Jim Stark (my father) was first introduced to flying as a teenager by getting a ride in a surplus P-51 owned by local legend Denny Sherman – talk about a fantastic Young Eagles ride! After that
ride, Dad was hooked, but it wasn’t until the early 80’s that he actually started chasing the dream of getting his pilot’s license.

Shortly after he got his license, he was fired from his job working with a local diesel fuel additive company and started working on Blackstone that same day. The funding for this company came entirely from debt, which meant he had to work hard to make ends meet with the family, and all non-essential expenses went right out the window. So long, 1972 Jaguar XJ6 with a bad head gasket, so long kids’ college fund, and so long flying.

Still, he had the flying bug and decided right away that Blackstone would support to aviation community by testing aircraft oils, not to mention he really needed the revenue. There are a lot of oil analysis labs out there, but only a handful test aircraft oils. There is a certain amount of knowledge you must have to test these oils correctly and deal with the challenges that come along with handling samples that are chock-full of lead. Along with being passionate about aviation, Dad had graduated from Purdue University with an Aviation Technology degree and A&P license, so the knowledge part came as second nature. He figured he’d learn how to deal with lead on the job.

Early Years
In the early years of Blackstone, we really didn’t test many aircraft oils—two or three a day if we were lucky. He made sales calls to FBOs in the area, but sales were slow. He had a lot more
success focusing on industrial factories and diesel truck fleets, but he never stopped trying to crack into the aviation market. Since this was well before the days of the Internet, they had to get
creative in figuring out how to tell aircraft owners and mechanics that Blackstone even existed. One of his early sales efforts was a sample kit mailing program. He bought a list of aircraft owners in Indiana, Illinois, Michigan, Ohio, and Kentucky from the FAA and sent one sample kit to everyone on the list. Another sales idea he had was the EAA airshow at Oshkosh Wisconsin. The funding to get a booth like we have now was out of the question, so he and my Uncle Bob (company Vice President at the time) decided to drive up to the show. Then they jumped a fence to get in (again, times were tight) and set an oil sample kit on the wing of every airplane they could find. As you can imagine, this type of “shotgun-marketing” didn’t result in a major influx of samples, but considering the fact that we still have customers today from these programs, both can be deemed a success, just a long time coming.

Enter Howard Fenton
We didn’t really hit it big in the aircraft market until 2002. That was when Howard Fenton called us up one day out of the blue and wanted to sell his company to us. He had first heard about us at
Oshkosh when some joker set a Blackstone sample kit on the wing of his Grumman Tiger, not knowing that he also owned an oil analysis company called Engine Oil Analysis (EOA).

EOA had been in aircraft oil analysis since the 1970s and was well respected in the aviation community. He sent in a sample to us to see what we were all about and decided he liked how we reported the results, so when it came time to retire from the oil analysis side of things, he called us to see if a deal could be made.

Jim and Howard hit it off right from the start. Both had worked for Dana for a lot of years and both were pilots, so Jim made a quick trip to Tulsa, Oklahoma to visit Howard, and the deal was done. Howard didn’t actually own a lab, he just contracted a local environmental lab to test his oil on their spectrometer. When they were done, they would give him a text file with the results and he had to hand-enter the data into his database reporting system. So basically, the only thing we bought from Howard was a client list, a bunch of historical data from the samples he tested, and all the goodwill the EOA name carried with it. Fortunately, Howard had roughly 3,000 happy customers, who trusted Howard’s judgement in choosing us as a replacement, so the transition for his customers to our service went smoothly. Blackstone was now a major player in the aircraft oil analysis field and we’ve never looked back.

40 Years of Growth
There were growing pains associated with taking on such a large chunk of business. The actual testing of the oil really hasn’t changed much over the years. We still offer the same standard
analysis as we did back in 1985. That includes the spectral examination, viscosity, flashpoint, and insolubles test. Spectrometers have improved significantly since 1985 in their reliability and ease
of use, but the accuracy of those old machines is comparable to what it is today, at least for our purposes, which means rounding to the nearest part per million.

As a lab, we needed to learn how to handle not only the large jump in aircraft samples, but the significant amount of leaded waste oil that goes along with it. Since a lot of the waste oil (including most of what we produce) in this world is burned for heat, and there is a limit to how much lead can be in your waste oil, it became obvious that we needed a separate lab just to handle the leaded oil, so we built one.

We also needed to develop a way to train new report writers. One of the things our customers like about our service as the comment section. It takes people to write those comments and the people we hire don’t tend to know anything about engines, so the training program we developed was extremely important in helping us expand and grow.

After Howard sold us EOA, he created a new company called Second OilPinion. Its focus was to inspect aircraft filters. We had never really wanted to get into the filter testing business. It was our
opinion (and still is) that this is something owners and mechanics can and should do on their own, but that doesn’t diminish the fact that Howard had a lot of people who were sending their filters to him for his opinion on what metal was showing up.

After Howard passed away in 2018, we decided to support the customers he was serving and developed our own filter analysis program. This program has come a long way over the years and we’re working on more improvements like developing a way to determine what alloy of metal is present when we do find a large chunk in the filter.

So, that’s a little history of where we’ve been. In thinking about the future, I am really looking forward to the widespread use of unleaded fuel. I believe this will be a boon to aircraft engine owners from a maintenance point of view. Leaded fuel is dirty fuel and the blow-by tends to be corrosive in nature. Once 100LL is safely eliminated, I predict a lot of problems like fouled plugs and stuck valves will fall by the wayside. From a business side of things, we won’t be able to use lead as a judge of how much blow-by is getting into your oil, but on the plus side, we won’t need to have a separate lab just to test aircraft oils anymore.

This past year we did have some major challenges processing samples in a timely fashion, but those have been addressed and our current turn-around time is back to 5 days. Thank you for sticking with us. We’re looking forward to a great 2025 and beyond.

By Ryan Stark|2025-03-14T15:02:04-04:00March 14, 2025|Aircraft, Articles|Comments Off

Is Fuel Dilution Just a Hybrid Thing?

A lot of worries pass through our lab each day. Some are warranted, like when knocking or coolant loss ends up manifesting in high bearing wear or coolant contamination in testing. But
just as many worries stem from common misconceptions and when that happens, we’re happy to assuage these concerns. Occasionally, though, a trend will coalesce in our data, seeming to
confirm a common assumption. Today we’re delving into the assumption that hybrid engines are more prone to fuel dilution than conventional ones, and we’ll try to determine whether or not that
should keep you up at night.

A Grain of Truth
A lot of hybrid owners dismiss fuel dilution in their samples, deeming it inevitable for motors working only part of the time. Others are less comfortable with repeated high fuel readings, and
seek advice on how to make it go away once and for all. To address these questions, we started by rounding up six engine models from various manufacturers. These were models used in both
hybrid and conventional vehicles, which also had relatively large sample pools in our database. A breakdown of the number of hybrid and conventional vehicles running these models is shown
in Chart 1.

We then recorded how many samples in each group contained 2.0% or more fuel. Anything less than 2.0% we consider fairly benign, but beyond that threshold, we start to wonder about fuel
system trouble. These results are shown in Chart 2.

Some engines ended up with only a slightly higher incidence of excess fuel in their hybrid models, while for others the disparity is quite significant. But on average 31% of the hybrids
contained excess fuel, with only 18% of the non-hybrids, seeming to confirm that hybrid engines are more prone to fuel dilution. Which leads us to the question – what’s so bad about fuel getting
into the oil?

Why Fuel Dilution Matters
When I brought my findings to Blackstone president Ryan Stark, he shared his own worst-case-scenario. Picture 1 and Picture 2 show a piston from his ’86 GMC Jimmy, clearly in pretty bad shape. Ryan had been dealing with excess fuel for a long while, which started to gum up his oil control rings. This led to the engine burning more oil and the ash leftover from the burning oil left deposits in the combustion chamber. Over time, these deposits got worse and the engine started to suffer from both pre-ignition and detonation. Eventually, the detonation caused a hole to form on the piston, pressurizing the crankcase, and blowing all the oil out the engine. Luckily, he noticed the oil billowing out of the back of the vehicle and the low oil pressure light on the dashboard and was able to pull over to the side of the road and stop the engine before oil starvation caused it to seize up.

Anyone would want to avoid a fate like this for their engine, so if you find persistent fuel dilution hard to accept, it really only makes sense to try and keep an eye on things using oil analysis. While we no longer have the oil reports from when this problem occurred back in 1996, we do have the last six samples from before Ryan sold this vehicle and you can see the results below (Chart 3). Ryan fixed the piston, yet the engine still had a persistent fuel system problem and the engine likely would have suffered the same fate if the problem was left unchecked. Ryan’s Jimmy was an extreme case. Modern engines are equipped to detect detonation and automatically try to fix the problem by adjusting the timing and fuel mixture. Still, if excess fuel is present, deposits can accumulate over time, but because they line the combustion chamber and form in the ring lands of the pistons, they don’t necessarily show up as wear in the oil. This is why we suggest watching the oil level on your dipstick. If your engine suddenly starts to consume a lot of oil, then it’s possible the oil control rings are no longer working like they should and other engine problems can’t develop. More often than not, poor wear doesn’t go hand-in-hand with excess fuel. A lot of times the fuel actually dilutes metals to such an extent that wear metals actually tend to read well below average, giving you a false sense of security.

After many years of testing oils we are constantly impressed by the resiliency of engines. We don’t live in a perfect world, and fortunately, we don’t have to. At least for a short while, most
engines can withstand some contamination or other mishaps, provided they are addressed promptly enough. That brings us to a couple potential mitigating factors, when it comes to
chronic fuel dilution in hybrid engines specifically.

Hybrids and Fuel Dilution
The combustion engines within hybrid vehicles experience operational factors that traditional vehicles do not. Most notably, they’re continually turn on and off for greatest fuel efficiency. A
hybrid vehicle being used primarily at lower speeds will rely mostly on its electric motor, which is also favored during acceleration. At higher speeds or during prolonged acceleration,
when more power is required, the combustion engine will kick on. This makes for a situation where it’s tough to know exactly how much the combustion engine has been used during a
particular oil run.

It also seems likely that this sporadic use is a major factor in the prevalence of fuel in hybrid engine samples. Most combustion engines run rich during start up, leading to small amounts of
fuel sneaking past the rings. Whatever ends up in the oil would typically evaporate with sustained engine temps of 212 degrees F. There are a few reasons why this might not happen,
however. Chart 4 is an example of a conventional engine that routinely had small amounts of fuel in its oil, likely due to stop-and-go city traffic. For a hybrid, though, every time the electric
motor kicks on, the combustion engine gets an opportunity to cool back down, leaving any fuel left to accumulate in the oil, rather than cooking out.

Of course, in theory, less use on the engine also means less chance for fuel-related deposits to form. Could the mix of factors impacting hybrids simply balance one another out? From here,
we wanted to answer the burning question: do hybrid engines experience more failures we could associate with chronic fuel dilution? This can be a tricky question to answer directly,
mainly because it relies on customer feedback. Once an engine has failed, it’s not everyone’s instinct to update us on what happened. Then again, some customers certainly do update, and we’ve yet to hear of a scourge of failed hybrid engines for any reason, much less fuel alone. Still, we wanted to see what the hard data had to say about it.

So … is fuel a problem or not?
To answer this question, we selected Kia’s 1.6L GDI engine for a closer look. Of the engines shown in Charts 1 and 2, it had the most representative average difference in fuel incidence
between hybrids and non-hybrids. It also had a fairly even amount of hybrid and non-hybrid samples in our system. We then counted samples that had one or more significantly elevated
wear metal. Of the 119 samples, 64 fit these parameters…yet a great majority were simply going through wear-in. Once we eliminated those, we were left with 12 high-wear samples. When we
further narrowed to samples with excess fuel, and separated hybrids from non-hybrids, the numbers became vanishingly small: 1 for hybrids and 3 for non-hybrids.

So, there does not seem to be a correlation between hybrids, fuel, and excess wear, much less premature engine failures. Regardless, it’s obviously better to have less (if any) fuel in your
engine oil; the less contamination, the more the oil is going to function as designed and tested by the manufacturer. So how can we accurately judge the risk, and mitigate fuel dilution, if noted?
Above all, it’s important to monitor the oil level at the dipstick – if fuel dilution is noticeably displacing the oil level, it’s worth inspecting the fuel system, no matter the reason. It’s also worth
making note if your engine is starting to consume oil, since it can be a sign that the oil control rings are no longer working correctly, which could lead to problems with your catalytic
converter as well as pre-ignition and detonation issues. Hybrid vehicle or not, any combustion engine can develop acute fuel system issues that are worth addressing promptly.

But as for the smaller, nuisance amounts of fuel dilution? It never hurts to work the engine a bit harder every now and again, to generate the heat it takes for fuel to evaporate—for example,
hopping on the highway for 15 minutes or so, if that’s not a normal part of your routine. More frequent oil changes can also help to flush out any fuel that’s mixing with the oil, before it can
accumulate to problematic levels. And of course, there’s always oil analysis! We’re happy to help you determine whether fuel is indeed excessive in your engine oil, and help assess what—if
any—action to take if so. Free sample kits are available at: www.blackstone-labs.com/free-testkits.

By Suzanne Herman|2025-03-14T14:23:19-04:00March 14, 2025|Articles, Gas/Diesel Engine|Comments Off

A New Wave

Way back in 1984, my father bought the most beautiful car I had ever seen: a baby blue 1972 Jaguar Series 1 XK6. It was in great condition and had that wonderful old leather smell that classic cars get. At one point when we were driving it around town, we passed another Jaguar and I saw my Dad wave at the other car and the guy in the other car wave back. As first I didn’t know why. I asked if he knew that person and he said no, he was just waving because the other guy also had Jag. That was the first time I had ever seen the “vehicle recognition wave.”

Wave-worthy vehicles
As you can imagine, not every vehicle has a wave. My wife currently drives a 2021 Mazda 3, and while this is a beautiful car in its own right, it does not elicit “The Wave” due to the fact that it’s so common. Some cars only get a wave on a part-time basis. My MINI Cooper convertible is like that. When I bought my first one, Fort Wayne didn’t have a MINI dealership, so these vehicles were pretty rare around town and it was common to get and give “The Wave” when I happened to pass one. Now that we’ve got a MINI dealership, they are pretty common and while I still tend to give “The Wave,” a lot of times the other owner isn’t even paying attention, or simply thinks I’m nuts because they don’t know they are supposed to acknowledge the fact that I’m driving the same type of car they are.

Motorcycle riders have what I consider the coolest wave – two fingers in a peace sign pointed down to the ground, similar to what you might do while using a hand signal the signify you are braking. This seems to be universal for all motorcycles no matter the make. I’ve seen it done between Harleys and sport bikes, BMWs and Gold Wings, appreciating the fact that they are members of a fairly small community of people who enjoy the freedom of a motorcycle.

Becoming a classic
In some situations if you hang onto a vehicle long enough, it can turn from something that never got a second look to one that now gets “The Wave.” That is what is happening now with my 1984 Chevy Full size ¾-Ton Custom Deluxe. You might remember this vehicle from such classic newsletters as “The Rebuilding of a GM 350,” “ZDDWhat?,” “The Renuzit Experiment,” and “This Ain’t Your Daddy’s ATF.”

When I bought this truck back in 1999, it was just another old truck. It had some rust but wasn’t completely rusted out, and I had visions of glory for it. I didn’t want to necessarily clean the body up much, but I did want to rebuild the engine to make it a “sleeper.” For those who don’t know, that’s a vehicle that doesn’t look like much but can easily take you off the line at a stop light.

Those visions quickly disappeared after my engine rebuild, which was significantly more difficult than I anticipated. Plus, the arrival of my son in 2004 and daughter in 2008 changed my perspective a little about what was important in life. So while the idea of going fast faded quickly, the need for a truck to do some work never did. As long as I have owned it, I would use this truck almost weekly every spring, summer, and fall. It was only two-wheel drive and did horrible in the snow, so I tried to drive it as little as possible in the winter, which is one of the reasons is hasn’t completely disintegrated into a big pile of rust at this point.

Over the years, I would only do the maintenance necessary to keep it running, and it would pay me back by hauling anything I threw at it. It has hauled some truly historic loads over the years, not the least of which was 5,000 lbs of dirt to the garbage dump (see picture). (Fun fact: garbage dumps will generally always take dirt for free; they need it to cover the garbage).

It’s not often I get to know exactly how much weight I’m hauling, but in this case I was able to find out because I had to stop at the scales on the way in and out. When I figured that difference it literally made my jaw drop. It didn’t matter that my truck was unmercifully overloaded (remember – this was just a ¾ ton, rated for 1,500 lbs) — I drove it all the way up a narrow dirt road to the very top of the dump without getting stuck once. Impressive!

Then much to my surprise, around 2020, I started getting “The Wave.” And this wave wasn’t just from other owners of what is now referred to as the “Square Body.” It seems to come from people who just appreciate my old truck (assuming they aren’t just nuts).

All good things must end
However just driving a “wave-worthy” vehicle isn’t reason enough to keep it. While owning this truck, I kept thinking if I could just spend a weekend working on it, fixing the little things, I could get caught up with it, but that never happened. The little things just kept on piling up and my patience had finally given out, so last summer I bought its replacement — a new 2024 GMC. So with that I say farewell and thank you to my now-classic Custom Deluxe. You always got me where I needed to go, assuming I didn’t let you run out of gas. May you always get the recognition you deserve.

By Ryan Stark|2025-02-11T10:49:23-05:00February 11, 2025|Articles, Gas/Diesel Engine|Comments Off

TBNs & TANs: Part 2

In our last newsletter, we did a deep dive on the science behind the Total Base Number (TBN) and Total Acid Number (TAN), and what information we can (and can’t) glean from these tests. Go back and check that one out if you missed it. For this article, we went into the lab for a more hands-on approach, and encountered a few surprises along the way. Let’s roll up our sleeves and start experimenting!

How Does Heat Affect the TBN?
We know a variety of factors impact the acidity of engine oils, but we wanted to isolate just one variable to measure its impact. Heat was the obvious choice, for two reasons. First, overheating is a common problem, and we often find increases in wear, viscosity, and insolubles after even brief overheats, so clearly heat causes the oil to change. Second, heat is pretty easy to replicate in a laboratory setting. So we broke out the hot plate and got to work!

We took three samples of Rotella T 15W/40 and tested oil at three different temperatures:
-212°F (normal operating temp)
-302°F (upper end of most oil temp gauges)
-392°F (a temperature your oil hopefully never sees, at least not for long!)

After reaching the target temperature, a portion of each sample was removed at 2-hour intervals throughout the 8-hour work day. It would have been nice to continue past 8 hours, since that’s really not very long in the oil analysis world, but fear of burning down the lab kept us in line. And once we took the first 392°F sample (see Image 1), our fears were vindicated.

The most obvious change we noticed was color. Image 2 shows that heat alone caused the oil to darken over time, and you can even see a color change between 302°F and 392°F, in Figure 3 below. So something is definitely happening as the oil gets hotter, but does it affect the TBN?

Once all the samples were collected, we tested the TBN, TAN, and viscosity, with the results shown in Figure 1. Eight hours at normal operating temperature had virtually no impact, and even at a relatively high 302°F, the TBN only dropped slightly over time. At 392°F, however, the TBN took a nosedive. By the 4-hour mark, it was already down to 1.8 — low enough that we wouldn’t suggest running the oil any longer — and it kept going down from there.

Even though this is a small sample size, the data clearly shows that high temperatures do cause the TBN to drop more rapidly, and the effect is more pronounced as time passes. Heat is far from the only factor impacting active additives out in the real world, where the oil also has to deal with the negative effects of friction, contamination, and fuel blow-by, just to name a few. But it doesn’t seem farfetched to think some of the damage from overheating could be linked to a diminished capacity to neutralize acids, so the TBN might be worth tracking in those instances when oil temps end up off the charts.

Surprising Finds
It’s worth noting that the TBN fell without throwing the viscosity out of whack — even the 8-hour sample at 392°F, the only one that ended up obviously thicker, was still within the normal range for 15W/40 (12.7 to 15.8 cSt at 212°F). We typically associate a thicker viscosity with “heat damaged” oil, but except in extreme circumstances, it looks like that viscosity increase is likely due to other factors, like high friction causing a breakdown of viscosity-improving additives, rather than just the heat itself.

Another surprise was that the 392°F samples also had a noticeably lower TAN reading. If you remember from the previous newsletter, the TBN tends to go down the longer the oil is used, and the TAN tends to increase, so at first this seems like a really weird result. What’s going on here?

Well, it’s important to remember that the TBN and TAN tests technically measure two different things. The TAN is a measure of how acidic the oil is, while the TBN measures the oil’s capacity for neutralizing acids. It appears that the excess heat has caused a chemical reaction that caused the oil to become less acidic while at the same time reducing the oil’s capacity to neutralize acids, likely by damaging the TBN-boosting additives or causing them to fall out of suspension. If this were a real used oil sample, acids would also be building up due to the other factors in the engine we mentioned above (contamination, blow-by, etc.), causing the TAN to increase. But since this was a controlled experiment where heat was the only variable, that didn’t happen here.

A Colorful Surprise
Before we end: a mystery! While we researching this article, we got curious about Aeroshell 100 Mineral oil. In theory, this type of oil shouldn’t have any additives at all (the normal additives in automotive oil can cause catastrophic detonation in aircraft engines), so we wanted to confirm that this oil would start out with a 0.0 TAN (it did) and a low TBN (also true at 0.0).

What we weren’t expecting was for the titration solution to turn bright purple! Usually samples stay evenly light yellow throughout testing, but once the basic solution (potassium hydroxide and isopropyl alcohol – the “Bruce” from Part 1) was added to this sample, the color drastically changed. A few minutes later, it began changing back to yellow and you can see that process beginning in Image 4. This made us even more curious, so we found a bottle of Aeroshell W100 (which does have some ashless-dispersant additives) and measured its TAN and TBN as well. They were 0.0 and 0.2, respectively. And lo and behold, this sample took on the same cheery magenta once the basic solution was added.

We aren’t sure why this happened, but we have a guess. Phenolphthalein is a pH indicator used in some other sorts of acid-base titration. It turns purple in basic solution, in the same way litmus paper turns blue. Phenolphthalein won’t show up in our spectral exam, since it’s made of the same elements as oil (C20H14O4), but maybe it or another pH-sensitive substance is present in these oils? We’re not sure! If you know the answer, we’d love to hear from you at bstone@blackstone-labs.com.

Answering the question! So, back to the main question — Do you need a TBN or TAN? The results of our experiments suggest that these tests can be helpful, especially if your engine oil got much hotter than it should. If you’re not having a problem with temps though, the main reason to get a TBN is what we discussed in Part 1 — seeing if the oil can be run longer.
In either case, the TBN or TAN readings provide additional data points, but they don’t replace the information on wear levels and physical properties found in the standard oil tests. Whether you’re concerned about heat damage or just looking to run a few thousand miles longer on the next oil, we look at all of the data to answer your questions and give you a complete picture of the engine’s health.

By Suzanne Herman|2025-02-11T10:15:22-05:00February 11, 2025|Articles, Gas/Diesel Engine|Comments Off

Finishing the RV-12

For those of you who have been reading these newsletters, you’ll know that I have been in the process of building a light-sport kit plane made by Van’s Aircraft called the RV-12. Last year I chronicled the progress and mentioned that I was getting close to the end. Well, thankfully the end has come, though I have to say it took quite a bit longer than expected.

Excitement/Burnout

We moved the project from the garage here at the lab to a hangar out at Fort Wayne International Airport in early July 2019. The days following the move were a time of excitement and hope, though that feeling wouldn’t last. My wife and I have been working on this project since the summer of 2016 and we were both kind of getting burned out.

However, actually being at the airport and talking with the other owners there helped keep our enthusiasm for the project going. In talking with the other homebuilt owners, it became apparent that even after it’s flying, there is always something to work on, but we didn’t worry about that much. We still had a lot of work to do just to get ours in the air. This was the part of the building process that’s a running joke among homebuilders — 90% done, 90% left to go!

Ironing Out the Details

Soon the prop was installed and the final fitting work on the cowling was done. We ironed out some bugs in the electronics and communication systems, most of which were mistakes we brought upon ourselves. Before too long, we came to the point where there was nothing left to do in the building instructions.

Next came a thorough checkout of all the systems. Van’s provides what they call the production acceptance procedures, which is a very helpful document that tells you how to go through all the systems to make sure they are set up and working properly. It includes things like “Move the control stick to neutral and measure the right aileron drop, it should be 1/4 to 1/2 inch.” Sounds easy enough, until you realize that just about every step requires some type of filling or adjustment on your part.

The Fuel Flow Blues

After a few months of work, we got to the fuel flow test. That’s exciting because right after that you get to start the engine for the first time. We had built the fuel tank about a year and a half earlier and up until then, it had not had any fuel in it. I was dreading putting fuel in for the first time, and for good reason, because as soon as I did, it started leaking out of a return line fitting.

That was a pretty dark point in the whole process because it meant I had to pull the fuel tank, open it up, fix the leak, and reseal it. Anyone who has ever worked with fuel tank sealant knows this is not fun stuff to work with, and it’s even less fun to try and clean it off parts. It’s also the point at which I realized that I had spent a significant portion of my life building something that would only fly about 120 knots max (with a tailwind) and wouldn’t even be able to haul my whole family while doing it. And to further sour my mood, this was mid-October and I knew at that point there was no way I’d be able to get it done in 2019.

Starting the engine for the first time!

Trying Again

So, after a good pity party and some time off, we got back to work. The fuel tank was fixed and reinstalled, though by that time it was too cold to get any serious work done at the hangar. That was okay though because it was also time to start the paperwork.

As some of you know, I inherited this project from my father and I can say for sure that the paperwork part would have been what he hated the most. Still, if you keep plugging away, eventually it all comes together. I was able to obtain a N-number (on my second try) and by the time spring rolled around, we were ready to test the fuel flow again and start the engine. As you might imagine I was fairly nervous about this whole process, but the fuel tank held up, the fuel flow test went well, and on May 3, 2020, our Rotax 912 fired up for the first time since it left Austria.

But is it Airworthy?

With the motor running and fuel tank sound, I was starting to feel a lot better about this project, though I still had the airworthiness inspection to deal with. This is generally the last step before you can fly and was a big unknown in my mind. It was also a little tough to get scheduled because not only did the FAA switch to a new and confusing online application process, the Indianapolis office had been closed since mid-March due to Covid-19.

They were just starting to reopen in mid May when I contacted them, but they were facing a serious back log of work that needed to be processed before they got to me. That basically left me with the choice to either wait until they got time to send someone up (for no charge) or I could contact a DAR (designated airworthiness inspector) and pay to have them take a look. Not wanting to delay this project into 2021, I chose the DAR and scheduled an inspection. Surprisingly enough, the actual inspection was painless and lasted just three hours. At the end I found myself wanting to show the inspector more of my airplane, so he could see the safety wire on the gascolator that I redid three times. Or admire the beautiful fiberglass work on the cowl that took several weeks to sand to perfection.

A successful first flight

Airborne!

With all the paperwork done and my airworthiness certificate on board, I was finally able to make my first flight on Monday July 13th. It went well, the wings stayed on, and the airplane showed no tendency to do anything crazy. As you can imagine, I was relieved. Now, on to some flight testing, as soon as I can get my transponder to report altitude… ahh the joys of homebuilt ownership.

By Ryan Stark|2025-02-06T15:38:44-05:00February 6, 2025|Aircraft, Articles|Comments Off

In the Thick of it!

Analyst Chris Tulley hits the Hot Rod circuit and reports the effects on his oil

In the spring of 1995, the editorial staff of the tenured HOT ROD magazine had a decision to make. The publication was set to host a run of brand-new HOT ROD Power festivals, muscle car meet-ups where locals could show off their own rides, see cutting-edge tech from manufacturers country-wide, and dream of new, faster ways to drain their bank accounts. Said magazine staff wanted to be a part of the fun and show off their own project cars, which would prove difficult, as they were based in Bakersville, Ca., while the inaugural Power festival was set in Norwalk, Ohio. The solution; drive their heavy Chevys, rat rods, and budget dusters over 2,000 miles to Ohio, then say a quick prayer to Lee Petty and the motor spirits that they could make it back home. 200 other drivers joined the ranks, sparking the birth of the HOT ROD Power Tour. “My car doesn’t just have to sit at a car show, I can drive it.”

So here’s the gist. Five racetracks in five days, spanning stretches of American highway and automotive history. The 30^th annual HOT ROD Power Tour just wrapped up June 15^th, where over the course of five days, over 5,000 cars, including my own 1970 Chevelle, and at least 100,000 attendees came together to sweat out 1,800 miles of tour.

Bouncing from drag strip to road course, this year’s tour kicked off at the National Corvette Museum in Bowling Green, Ky., where the tour ended in 2023. Bright and early Tuesday morning, the caravan headed south to Nashville Superspeedway, where participants could spin a few laps. Day three; The University of Louisville. Next stop, National Trail Raceway, outside of Columbus, Ohio. The checkered flag flew over mecca; the Lucas Oil Raceway in Indianapolis. That’s where the tour will start in 2025.

I wanted to know how a tour like this would affect our favorite topic; my oil. I have been blessed to go on about 10 Power Tours so far with my father and our Chevelle. This is the third engine in the car, and I’ll have a fourth upgrade next year. This year we ran a 1969 Chevy 355cid small block. So I wanted to know how the oil looked to start, and what condition would it end up in nearly 2,000 miles later.

First, we took a sample of virgin Valvoline Full Synth 10W/30 (Figure 1). Calcium, a detergent-dispersal additive, was the leading element at 703 ppm. Magnesium, zinc, and phosphorus all read above 500 ppm, and there was some boron and molybdenum in the mix as well. Pretty typical cocktail of additives, overall. The TBN started at 5.3. The higher that TBN reads, the better active additives can stave acidity and corrosion.

For the second sample (Figure 2, pink column), we drained the engine, added the Valvoline, and immediately pulled a sample via the dipstick. There was some iron and lead present from the previous fill, at 16 and 28 ppm, respectively. Carryover is inevitable, as oil changes fail to get every last drop out of the galleys channel of the block. We had used an oil additive recently, something along the lines of Lucas Oil, so calcium bumped up to 1,453 ppm. Zinc and phosphorus jumped up a little as well, but magnesium dropped by over 50% to 298 ppm. The viscosity increased as well, as did the amount of insolubles, so maybe that magnesium was grabbing carbon build-up to keep it from settling and coagulating. At least, that’s my idea of what a detergent dispersal does. Why the magnesium decreased is beyond my chemical knowledge. I’m more of an expert at “press gas, go fast”, it seems.

Sample number three (Figure 2, blue column) looked better than I expected, which is good for the engine, but it doesn’t make for the most exciting article. We pulled the sample in the middle of the week, then topped of the engine with about 4 ounces of fresh Valvoline. This sample saw roughly 900 miles of highway and backroads, and only an hour of road course time. As much as I wanted to drag race throughout the week, my tire budget didn’t approve.

The most notable addition to this analysis was fuel dilution at 1.3% by volume. Did the engine get above 190°F during this run? Obviously. But think of how many times the engine was stopped and restarted. Between gas stations, hotels, breakfast, and the many times I decided I needed a better parking spot, I bet we cranked the engine at least 15 times a day. That’s ample opportunity for fuel to enter the block. It wasn’t enough fuel to thin the viscosity below specifications for 10W/30, which is the main concern with fuel in oil. Fuel wasn’t present in any of the other samples. Iron, from steel parts like cylinders, shafts, and lifters, is the wear metal that tracks closely with use, and it increased by just 4 ppm. Lead dropped by 2, showing that the bearings didn’t wear a bit. That’s encouraging, because I certainly got on the throttle.

The final sample (Figure 2, orange column) reveals a cool instance of cause and effect. So imagine thousands of hot rods coming through a small town in southern Kentucky. Every red light, every stop sign was backed up for miles. There wasn’t a single Slim Jim or Diet Coke left in the county. I have radiator for a big block, and two electric fans to combat engine overheating. At one point, in the bumper to bumper traffic, my fan relays blew, and my engine temps rose to nearly 260°F, roughly 40° too high for comfort. As we were literally sweating out the situation, my oil was unable to cool the engine, an imperative feature that could have resulted in a tow-ride home.

After replacing the fuses, we never had another mechanical issue. The viscosity of the sample came back thicker than expected for 10W/30, an obvious sign of the high heat. Now if you think a little heat can impair classic American ingenuity, you’d be right in a lot of cases. But not mine. Iron read at 20 ppm once again. Sure, take into account up to 5% deviation from the testing equipment. Maybe iron was actually at 18 or 22 ppm. Either way, running at high temps without a fan did cause my oil to thicken a bit, but it didn’t hurt the wearing parts at all. Not a single increase in wear metals down the line.

The last kicker was the TBN reading. We only tested it on the virgin and the final samples, to see an exact start and finish. Remember when I said the TBN read at 5.3 in the virgin sample? It ended at 5.2. 1,896 miles later, and the active additive in the oil only degraded by a fraction of a decimal. The low end of a TBN is 2.0. After that, an oil can turn acidic, leading to corrosion.

Not only is that a testament to the additive package in Valvoline (not sponsored, but willing), but the overall efficacy of the engine and the American spirit.

We’ll see how next year goes, but no matter what, my Pops and I are in it for the long haul. Happy 30^th Anniversary, HOT ROD Power Tour!

By Chris Tulley|2025-01-14T15:23:48-05:00January 14, 2025|Articles, Gas/Diesel Engine|Comments Off

The Price We Pay to Soar

How does flying in the Air Race Classic affect engine wear?

Let’s start this story with a question.

Mark has a truck – let’s say it’s a red F150. Mark consistently runs the engine 70 MPH on the highway every day on a commute to work with nothing in the bed.

Mark’s buddy Dave lives next door, and Dave also has an F150 (this one’s blue), with the same engine, and he works in the same place as Mark. So the two guys have the same exact commute, except Dave constantly hauls 8 kegs of beer to and from work, and he always pulls a trailer that’s loaded up with about a thousand pounds of dumbbells and free weights.

Which engine looks better in oil analysis? Mark’s, right? His engine sees much lighter use—no heavy loads in the bed and no towing, so he’ll have less metal in the oil. That makes sense. The same thinking goes if you compare driving 50 miles on the highway vs. 50 miles on the race track: track use is harder, and it’ll make your engine wear more. And indeed, the data backs this up.

But is that true for airplane engines?

We don’t see quite as many samples from aircraft engines that are run harder than others to be able to determine whether there’s a difference. Either you’ve got an aerobatic airplane that does mostly aerobatic flights, or you’ve got a trainer that sees everything from countless touch and go’s to multiple cross-country flights on every oil run. Maybe you’ve got your business plane or transport plane doing mostly long-haul flights and not much else (imagine doing aerobatics in your family hauler, with the kids strapped in the backseat). So while we naturally expect harder use to result in more metal, that’s a little harder to quantify in the aviation world than it is in the automotive world. But then there’s Joelene.

Joelene
Joelene is a close friend of mine who has been sampling her 1978 Bonanza’s Continental oil with us for several years. She keeps her IO-520 active enough that corrosion has never really been a problem. Joelene does a nice mix of cross-country flights from the Midwest down to Texas, has the right instruments to keep her current and proficient, and she’s not shy about helping with Young Eagles flights at nearby airports. Overall, most of the flying she does is relatively easy cruising without a lot of hot/cold cycles, and she’s got several pages of nice, stable trends to back it up.

The Air Race Classic
A couple years ago, Joelene got into racing her Bonanza. In 2022, she participated in the Air Race Classic, a ~2,200 nautical mile, four-day race for teams of two (or more) women pilots. The race traces its roots back to the days of Amelia Earhart and her contemporaries, when women weren’t allowed to race with men, so they started their own cross-country race.

This past summer, I was her teammate in her Bonanza. Our race started in Carbondale, Illinois, and ended in Loveland, Colorado, with stops in Indiana, Michigan, Ohio, Minnesota, Missouri, Oklahoma, and Kansas along the way. All told, we traveled 2,269 nm in just over 19 hours, going full-throttle the entire time. This was a little different than the normal kind of flying Joelene does.

Looking at the Numbers
After her first race in 2022, Joelene and I looked at her engine oil test data to try to figure out how much “damage” was inflicted on the engine parts by participating in the race. The biggest thing we had noticed was that make-up oil had gone up from 2.5 quarts in 27 hours to five quarts in 34 hours. There was a little more nickel, too, but nothing noteworthy. Realistically though, one data point isn’t exactly enough to come up with any hard-and fast conclusions about the engine.

Guess we better keep racing.

So after being a part of the Air Race Classic this year, she now had two sets of data to compare to her normal trends. When I asked Joelene if I could use her data for this article, she replied, “Yes! As long as you don’t tell me I can’t race my Bonanza anymore!” We would never.

Non-Racing vs. Racing Wear Numbers
Joelene has a total of 19 samples on file with us over the last five years, and two of them are the race samples. It isn’t a huge sample size, but it’s worth taking a look at.

She averaged a typical 32-hour oil change interval over her 17 non-racing sample. While racing, the average interval is 29 hours. Metal counts are in parts per million.

Aluminum, chrome and iron inched up a bit, copper and lead both managed to improve, and nickel doubled. So, in this case (lead and copper being the exceptions), racing does cause a little more wear for Joelene’s Bonanza. Enough to stop Joelene from racing next year, or raise any red flags on our end? Nope, it’s not that significant. Keep in mind we’re still talking about microscopic metals in parts per million, so we’re not talking about a lot of metal overall—the harder use does affect the engine, but not to the extent that she needs to change what she’s doing.

Why did copper improve? We don’t know. Lead, on the other hand, is a bit more explainable. It comes from 100LL fuel blow-by, which tends to read higher when flying at higher altitudes and lower at lower altitudes. With less air pressure on the crankcase at higher altitudes, more blow-by escapes past the rings, and you end up with more 100LL in the oil.

As part of her racing strategy, Joelene tends to fly quite a bit lower than normal so that she doesn’t spend as much time climbing at slower groundspeeds (since you don’t often make up a lot of speed with tailwinds on shorter legs). Most of the legs of our race were flown at the absolutely lowest FAA minimum safe altitude during the race, which was quite a rush! And also, that means lead, from blow-by was a little lower.

Still with us? There’s just one more factor to note.

Oil Consumption
One of the biggest things Joelene noticed when she’s racing her IO-520 and running wide open the entire time, compared to when she’s flying a bit more tepidly, is that her engine consumes a good deal more oil. How much more oil? When Joelene isn’t racing, her engine burns an average of 1 quart of oil every 25.7 hours, or 0.04 quarts/hour. When she is racing, oil consumption increases to 1 quart every 4.8 hours, or 0.17 quarts/hour. She has a 12-quart sump, but she keeps the oil level at about 10 quarts — anything above that just ends up on the belly on the plane.

So, when Joelene is racing she’s roughly refreshing 50% of the oil during a given run, which means the metal counts we provided above would essentially be diluted by about 50% at the end of the run.

To get the exact dilution factor we’d have to figure out how many hours into the oil run she added each quart of oil, then figure out how much time that oil spent in the engine, and do a whole lot more math. Suffice it to say, the additional make-up oil is making her racing numbers look better than they actually were. It potentially doubles the wear rates over her non-racing samples. I won’t put those numbers here, so Joelene doesn’t have to look at them in black and white (and since the numbers, technically, would be just an estimation anyway), but you can imagine what they’d be: 50% higher.

Conclusion
Did the engine make more metal? Require more make-up oil? Yep, it did. Makes sense, right?

Joelene only gave me permission to write this article and use her data as long as I didn’t tell her she couldn’t race her plane anymore. You’re reading this article, so the conclusion is that I’m not going to be telling Joelene not to race her plane anymore. And rightfully so.

Even with all the data and trends, the metals we’re reading are microscopic, in parts per million, so the increased wear rates aren’t significant enough to suggest we’re looking at part numbers or any serious engine damage. The wear rates are a little higher than average, but that’s nothing compared to all the fun she has racing—the challenge, the excitement, the camaraderie, and the memories. Worth it!

When we have automotive customers whose engines wear slightly more than average because their engines are used for off-roading, or hauling, or even a lot of idling, we remind them that the metal is probably just the small price you pay for all the fun you’re having. And that’s the same thing we’d say to Joelene with confidence: yes, your engine wears a little more on the races, but not nearly so much that we think you should stop racing. Besides, it’s better than *not* flying your airplane and letting it corrode from the inside out. Might as well fly it!

We’re excited to cheer on Joelene (and the rest of those amazing ladies) in next year’s race, and we are looking forward to seeing that little sample bottle of black gold to see how the engine fared.

By Amanda Callahan|2025-01-14T14:48:45-05:00January 14, 2025|Aircraft, Articles|Comments Off

Landslide!

Imagine the awesome event of a landslide. There’s no doubt it’s a brutal force of nature. If you’re unfortunate enough to be caught in one, you might not survive. A landslide is gravity pulling terra firma down a slope with such force that it takes all things, natural and manmade, with it. The very earth that supports us unmoors from its surroundings, changes shape, and becomes destructive. While it may not be obvious at first glance, this landslide can help us understand oil analysis.

Take a picture

Back to your mental image of the landslide: it starts off with a few pebbles rolling down a hill. Those pebbles strike others, and the dirt slide gains momentum. The process escalates and the mass of the movement increases. Larger rocks and patches of earth are dislodged, and the process continues until the whole hillside is involved, taking trees, boulders, and anything else in the way. Now stop: Take a mental picture of the landslide in full force. Step back and look at the frozen picture. Everything on the hillside that started off peacefully and at rest is in the process of roaring toward the bottom of the slope.

If you looked at your picture of the landslide from afar, you’d see a cloud of dust and dirt at the front edge of the sliding mass, and lingering far behind it. The dust cloud itself would actually hide much of the larger detail of rocks and trees crashing along the slope. Without looking at the larger debris contained in the mess, could you determine the makeup and extent of the landslide from the dust cloud alone? For the most part you could, and that’s how oil analysis works.

Normal vs. abnormal

One of the limitations to oil analysis is that we can only tell you about the wear metals that we can see with the spectrometer, which are between about 1 and 15 microns in size. (How big is a micron? One-millionth of a meter. One inch contains 25,400 microns. The period in this sentence is about 615 microns.)

If you have a mechanical problem with your engine, the oil filter should collect the larger metallic particles (usually those larger than 40 microns). These are the boulders in the landslide. There is also a wide range of rocks and stones present in the landslide that don’t become airborne. They still ride the slide to the bottom of the hill, but they don’t hang suspended in the dirt cloud. These are the particles that fall out of suspension and don’t make it to the lab with your oil sample.

Then there’s the dust cloud. We compare the “dust” we see in an oil sample to what is average for a particular type of engine, transmission, differential, etc. We expect all mechanical machines to produce wear in the course of normal operation. But there is normal wear, and there’s abnormal wear. When we find abnormal wear in your “dust cloud,” we may be looking at a potential landslide in your engine.

Avoiding the trees

Fortunately, we don’t have to wait for a landslide to occur before we can determine what’s going on your engine. While the dust cloud accompanying the slide is a one-time occurrence, we can repeatedly analyze the oil from your engine and see trends developing. One snapshot gives you a look at whether the dust we find appears normal or abnormal. But a series of snapshots gives us a clearer picture of the condition of the engine. By trending the results from one oil change to the next, we can see whether the dust cloud is growing or subsiding. If it’s growing, eventually there will be boulders and you’ll need to take action to save the engine.

Occasionally we are asked about the dust: How much is too much? In other words, when someone has a particular metal that’s reading high, they often want to know how high it needs to be before they really start to worry. The answer is, there’s no single answer.

Lots of things affect the amount of wear we find — the type of engine it is, how it’s driven, and what conditions it’s operated in. What’s more important than the level of wear is the wear trend that’s developing. Someone who routinely races a Subaru 2.5L engine in Las Vegas is probably going to find higher wear on a routine basis than a person who uses the same engine to mainly go to work and the grocery store in Minnesota. If the racer’s wear is always high, and it always reads at about the same high levels from sample to sample, we’d probably consider it normal for that particular engine. If the grocery-store engine was producing low, steady wear, and then wear suddenly jumped up to the racer’s levels, we’d worry. That’s why it’s important to establish wear trends for your particular vehicle, and why we can’t always say, “Okay, when iron gets to X level, it’s a definite problem.”

Avoiding the full-on, catastrophic landslide is not hard to do if you practice routine oil analysis. To keep the boulders and trees out of your engine, pay attention to what you find when you change the oil or have it changed. Some metals are normal in new engines, but once past 10,000 or 15,000 miles, you should not be normally finding any metals that you can see. If you do find metal, it’s probably not too late to stop the slide — but it’s better to avoid it in the first place, if you can, through the trend analysis of your engine’s wear.

By Jim Stark|2024-09-19T09:01:39-04:00June 12, 2024|Aircraft, Articles, Gas/Diesel Engine|Comments Off

ZDDWhat?

Any search on the Internet today with regard to oil additives will eventually bring up the supposed problem that there is a lack of anti-wear additive called zinc dialkyl-dithiophosphate (shortened to ZDDP and showing up as the elements zinc and phosphorus ) in the new oils. People are worried the lack of ZDDP is causing the destruction of many older flat-tappet engines.

This first part of the problem seems to stem from an EPA mandate that all oil companies either reduce or eliminate ZDDP from their oils. While I’m sure the EPA mandates a lot of things, if they are telling the oil companies to get rid of this additive in their oils, the oil companies certainly aren’t listening.

Any automotive engine oil sample you send will have both zinc and phosphorus in it and at fairly high levels (anywhere from 500 to 1,000 ppm and often times a lot more). But is the Zn and P in the form of ZDDP? Are there other compounds that could leave Zn and P in the oil? So the first part of this issue isn’t really an issue at all, and that brings up the second part of the issue.

Is a lack of ZDDP really a problem for flat-tappet engines? My first inclination would be to say no, and that’s because 99% of all piston aircraft engines don’t use that additive in their oil.

Most aircraft engines are air-cooled, so they tend to run hot. Due to this, they require the use of an ashless oil. That simply means that when the oil burns, it must burn completely and not leave any ash behind. Aircraft engines are mostly flat-tappet engines and they seem to get along just fine without ZDDP. So is the second part of the problem really a problem?

I’m a mechanical engineer by training, and when I was in school, we learned the best way to answer that would be to follow the scientific method.

The Scientific Method

If you made it this far, then I guess you weren’t tired when you started reading this because the mere mention of the scientific method has been known to cause many a high school and collage kid to nod off almost immediately. For those who don’t remember what that method is, here’s quick refresher. But wait, before you continue reading, go get a cup of coffee because I don’t want to lose any of you.

Define the question
Gather information and resources (observe)
Form hypothesis
Perform experiment and collect data
Analyze data
Interpret data and draw conclusions that serve as a starting point for new hypothesis
Publish results
Retest (frequently done by other scientists)

1. Define the question: Is the lack of ZDDP a problem?

Apparently, the lack of ZDDP in the oil is causing the demise of older engines that still use flat tappets because without that anti-wear additive present, the camshaft lobes and tappets grind down to nothing, especially when the engine is brand new.

The thing is, this doesn’t necessarily happen to all of the camshaft lobes, just a select few. The magazine Popular Mechanics recently did an article on this and they showed a picture of a camshaft with one lobe worn down to nothing. I have my doubts about this because if there really was a problem with the oil, wouldn’t it affect all of the camshaft lobes and not just one? I don’t pretend to know all there is to know about camshaft design and surface hardness, but I know enough to reason that all of the lobes and tappets are lubricated by oil, and if the oil was indeed substandard, then wouldn’t it affect all of the lobes the same way?

Figure 1: Aeroshell W65

This brings us to our next point: What would happen if you ran an oil that didn’t have any ZDDP in it at all? If that additive is so important, wouldn’t the complete lack of it cause camshafts to self destruct in a short period of time? I don’t think so, because aircraft engines do it all the time and the good majority of those last to 2,000 hours and well beyond.

2. Gather information and resources (observe)

Not much to do here. I did have to order some oil that didn’t contain ZDDP. That was Aeroshell W65 (see Figure 1). It’s a 30W oil commonly used by aircraft engines during colder months. That viscosity is close to the 10W/30 (at 210ºF) that I’ve run since the rebuild. It’s important to note that while this oil doesn’t contain any additives that we read, it is known as an ashless dispersant oil, so there are some additives in there.

3. Form hypothesis: The lack of ZDDP isn’t a problem at all

Never did understand this part. Isn’t it the same as define the question? Maybe I was asleep at the time. In any case, here is goes. I don’t think the lack of ZDDP is a problem at all, based on all of the normal looking aircraft engines we analyze that do not run that additive.

4. Perform experiment and collect data: My own engine

Since this is my experiment, I decided to use my own engine at a guinea pig. Back in 2004 I rebuilt the GM 350 engine in my 1984 Check ¾ ton pick-up truck. The rebuilding process didn’t quite go as planned but the engine has been running well since then and since it has flat tappets, I thought it would be a good engine to test. I control the operating conditions and another plus is that if the engine decides to explode, I’m the only one to blame and I won’t sue myself for damages, though there may be some lawyers who would take that case.

I changed oil originally back in February of 2008. Here is the report on the oil that I took out (see Figure 2). Not the best data, especially at lead, from bearings, but at least it’s consistent.

Figure 2: The original oil was Havoline 10W/30

5. Analyze data

That was the easy part. I’ve been looking at oil reports every afternoon since 1997, and I don’t have to pay for the samples.

6. Interpret data and draw conclusions that serve as a starting point for a new hypothesis

After 16 months and 1,943 miles I decided it was time to change the oil. You can see the results in Figure 3. At first glance it would seem that the engine’s steel parts didn’t really agree with the new oil. Iron went up to 37 ppm, which isn’t really a problem level, but more than I had been seeing.

Figure 3: The first run on Aeroshell W65

However, it’s also important to note that this was the longest I had run the oil since the rebuild, both in time and mileage. Also, the engine doesn’t have any emission controls (don’t tell the EPA) and had an open breather coming off one of the valve covers.

So with it being exposed to the atmosphere, there is always a chance for rust to form on the parts, and that could account for the increase in iron. Lead was still excessive, but that didn’t really change, and nothing else unusual was present.

Note that this oil still had some additive in it (molybdenum, calcium, phosphorus, and zinc). These are leftover from the last fill and it turns out for this engine, about 20% of the old oil remains in the engine after an oil change. This is important to note because 20% of the metals are leftover from the last oil fill as well.

But the data from one sample doesn’t make for good science and I still had more Aeroshell to use, so I ran it again. This would help make sure the data was consistent and also make sure the lingering additives from the regular engine oil weren’t affecting my results.

Figure 4: Wear improves!

The second oil was changed on October 30, 2010, after another 16 months and 1,921 miles this time (see Figure 4). At first glance you will notice a nice improvement in wear, especially lead. Does this mean the Aeroshell W65 is actually working better then other oils? Alas, no. When you don’t see in the data is that I took a 675-mile road trip during this oil run and I strongly suspect that highway trip is the reason for the improved wear, rather than any miraculous improvement due to Aeroshell.

This is an important fact to think about whenever you are looking at someone else’s oil report. Driving conditions can have a large effect on the data and unless you know what those conditions are, it is very easy to draw the wrong conclusions.

The conclusion I can draw is that no, my engine did not self-destruct running this oil. I didn’t actually visually inspect the camshaft, before or after this test, so I don’t know how much, if any, actual wear occurred in that area. So the test isn’t perfect in that regard, but I can say the engine is still running just fine.

So do we have a starting point for a new hypothesis now? Yes. Would my engine be okay if I had used this oil during break-in? Maybe, but we’ll won’t know until I rebuild another engine. When I do, I plan on use another oil that’s popular in the aircraft community: straight mineral oil with no additive whatsoever. Probably about 80% to 90% of the aircraft engines are broken in on this type of oil and they seem to do fine.

Are there any other new hypotheses? I’m sure there will be many that come by and most of them will center on how this test is invalid for some reason or another. And in response to that I would refer to section 8 of the scientific method and see what happens if you have the balls!

7. Publish results: That’s what you are reading

Not much to talk about here, and that brings us to our last point on the scientific method

8. Retest (frequently done by other scientists)

In this case, the other scientists are you and while I’m not suggesting any of you run Aeroshell in your automotive engines, you can use oil analysis to help solve questions you may have. Is synthetic oil really better than petroleum oil? Is that additive you’re using really helping? Feel free to draw up your own hypothesis and run your own tests. Don’t just buy an oil or additive, start using it, and then never stop just because the engine is running just fine. And by all means, don’t just take the word of the people who make oil and additives. Be objective and run some testing. I think you’ll be surprised by the results.

By Ryan Stark|2024-09-19T09:07:44-04:00January 16, 2024|Articles, Gas/Diesel Engine, Marine|Comments Off

To All the Oils I’ve Loved Before

I get asked on a regular basis what type of oil is the best, and we typically don’t give out recommendations because we see very little difference between brands. But that doesn’t mean I don’t have favorites. For me, there is a lot more that goes into picking a favorite oil than just how well the engine wears while it’s in use.

One factor is what Dad used. I can remember “helping” change oil with him back in the ’70s when the oil cans were round and you had to jab a separate spout into the can just to pour the oil out. Back then he was a Pennzoil man and I didn’t think to question why. So when I started buying my own oil and changing it, I thought about using Pennzoil, but being a bit of a rebel in my teenage years, I wasn’t going to do everything like Dad did.

I started out liking Texaco Havoline. It came in a cool black bottle and Texas was far away from Indiana so the oil was kind of exotic. I used it for years and my engine never blew up so it mast be good oil right?

Then I found Castrol GTX. Their white bottle wasn’t all that special, but they did offer a free NFL hat if you bought a case. That was an excellent reason to switch in my mind, and I still wear my Detroit Lions had with pride. (Yes, that’s right, I’m a Lions fan, and mark my words, they will win it all someday! If the Saints can win it, there’s always hope for the Lions.)

My engine ran for years on Castrol and never blew up, so that must be good oil right? Then Castrol quit offering hats, so it was time to switch, and I decided to try Quaker State. Made from sweet Pennsylvania crude, I’m sure. They had a cool green bottle and my engine never blew up using it, so it’s good oil.

But I was never completely sold on Quaker State, and when I found Wolf’s Head oil, I know it was time for a change. I’m not sure, but I suspect it’s made from the first pressing of dead wolves’ heads, and while the animal lovers might not approve, it’s better than Baby Seal Head oil, so I didn’t feel too bad running it. That oil seems to work just fine, my engine never blew up using it, but it was kind of out of the way for me to buy it, so I switched again.

This time I cheaped out and went with Meijer oil. For those who don’t know, Meijer is a big superstore like Wal-Mart, and after running a test on it, it turned out to have the exact same additive package as Castrol, my former favorite, so I was sold.

Until this point I had steered clear of non-name brand oils (their bottles aren’t very pleasing to the eye), but then I realized that big chain stores don’t really make oil, they just buy it from a major oil company and repackage it as their own. This revelation sold my father on Wal-Mart’s Super Tech oil and almost sold me on Meijer forever, but then my wife started doing all the shopping. I never made it to Meijer anymore, so once again it was time to switch.

Since then I have never really settled on one brand. Working at an oil lab, I’m interested to see what different oils people are using, so I switch on a regular basis and I mostly go with what’s on sale. Valvoline, Pennzoil, Mobil, it doesn’t really matter. I’m too cheap to go with synthetics, but I can still be swayed by a cool-looking bottle every now and then. And given my fondness for a low price, I recently found a new favorite oil.

All kidding aside, we really don’t care what oil you use. Some guys swear by this oil or that oil, but they all do the same thing and we honestly don’t see any appreciable difference in wear when people switch brands. We think oil is oil, and we’re sticking with it.

By Ryan Stark|2024-09-19T09:08:28-04:00July 28, 2023|Articles, Gas/Diesel Engine, Marine|Comments Off