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

TBN/TAN: Do You Need One?

“Do I need a TBN?” It’s a question that comes up a lot. The TBN is a test we do on engine oil, while the TAN is meant for transmissions and other gear lubes or hydraulic oils. These tests are widely discussed on internet forums, where facts and misconceptions can be hard to distinguish. So let’s dig into the science behind them!

What is a TBN or TAN?

The Total Acid Number and Total Base Number are ways to determine how acidic oil has become (TAN), or how effectively it can neutralize the acids that form from combustion and other factors (TBN). An increasing TAN indicates more acidity, while a decreasing TBN shows an oil’s acid-neutralizing additives are being used up. You may remember the pH scale from science class. pH is a more familiar measure of acidity in everyday life. So why don’t we use pH on oil?

pH stands for “potential of hydrogen” and measures the flow of hydrogen ions in a water-based solution. pH doesn’t apply to oil because these ions can’t flow through oil – it’s a poor conductor. That’s why oil is used as an insulator for transformers and other applications that call for interrupting the flow of electrical current. Fortunately, we can use titration to get around this obstacle. Titration is used to determine the concentration (in this case, the acidity level) of an unknown solution (oil) by exposing it to measured quantities of a known solution (acid or base).

Running the tests

We start by mixing one gram of oil with a happy blend of toluene, chloroform, isopropyl alcohol, and a splash of H₂O. (Kids, don’t try this at home!) The solvent breaks down the oil into a solution that is a better conductor, so we can measure the pH. The next step differs slightly for the TAN or TBN.

For the TAN, we add a cocktail of chemicals – let’s call it Bruce – to the toluene solution, a little at a time. This continues until the pH reaches 11. The lab techs then use an equation to calculate the TAN from the amount of Bruce added to the oil-toluene blend.

The TBN follows a similar methodology, except the solution added is more acidic – more of a Boris than a Bruce.

The end goal for the TBN titration is a pH of 3, and as with the TAN, the lab people are doing some math to transform the amount of Boris added to the oil into your TBN number.

Why get a TBN?

As the oil circulates through the harsh environment of a hot, running engine, combustion causes acids to form. These acids can cause increasing wear and corrosion. To prevent this, the oil manufacturers add detergent additives to the oil, which help it buffer those acids and stabilize the oil’s pH. The higher the TBN, the better your oil can resist becoming acidic. That’s the main reason to check the TBN. It’s a helpful data point if you want to extend your oil change interval beyond manufacturer recommendations.

The TAN does essentially the same thing, but we use the TAN on oils that don’t have detergent additives (like hydraulic oil and ATF). Some industrial equipment manufacturers will set standards for when to change the oil based on the TAN.

Which oil has the highest TBN?

The TBN is mainly based on the amounts of calcium and magnesium (detergent additives) in the oil. Oils with more of those additives typically have a higher starting TBN, and those with less will rank lower on the list. Is more better? Not necessarily (and we’ll get into that a little later). Meanwhile, Figure 1 lists a slew of virgin engine oils and their average starting TBNs, from highest to lowest. The progression isn’t perfectly consistent, because we don’t test for every conceivable substance the oil manufacturers might include that determines the TBN. chart showing the TBN for various types of oil

As you probably know, the TBN drops pretty fast when you start using the oil. Then it levels out and drops more slowly, the longer the oil is run. Figures 2 and 3 show two types of Mobil and how the TBN tends to fall as acidic substances start to “use up” the detergent additives. That’s what they’re there for, and we consider any TBN over 1.0 sufficient, while a TBN of 2.0 or greater is ideal when choosing to run the oil longer than you currently are. Note that ppm calcium and magnesium stay roughly the same – it’s their ability to neutralize acids that decreases.

chart showing the TBN and TAN of Mobil 1 5W/30 at various mileage intervals

Figure 2: This oil has an average starting TBN of 7.5. Note the roughly inverse relationship of the TBN and TAN readings; as the TBN decreases, the TAN increases, as less “active additive” is available to neutralize acids.

chart showing the TBN and TAN of Mobil 1 Annual Protection 0W/20 at various mileage points

Figure 3

Figure 3: This oil has an average starting TBN of 7.9. The chart shows the same fairly predictable drop in TBN as miles increase. Interestingly, the TAN is less predictable, probably due to factors outside the scope of this newsletter.

Is more better? A look at two novel blends

It’s easy to see how you might feel like you want an oil with a starting TBN that’s as high as possible. But Figure 1 makes it clear that oils with all sorts of starting TBNs are available. Did the manufacturers at the low end of the scale just cheap out on additive? Not at all. Oil manufacturers have to cater to an array of unique engine designs, operating conditions, etc. As technology evolves, so does oil.

Joe Gibbs

See, for example, Figure 4, which lists a few different samples of Joe Gibbs Driven D140 oil. It had the lowest average starting TBN (4.4) thanks to fairly low levels of calcium and magnesium. This left the TBN between 2.0 and 1.0 after just 5,000-6,000 miles. But the engine that produced those numbers was a Porsche 911 that had excellent wear trends (see Figure 5). This oil is specifically formulated with lower calcium and higher moly to combat low speed pre-ignition and reduce abnormal combustion and wear. While we can’t say whether this oil really does reduce LSPI, it seems to work as well as others do and we see no problems with the novel additive blend.

Figure 4

Figure 5

Figure 5: Wear trends for the five samples in Figure 4 (and one additional sample, not included there because TBN and TAN were not requested). Wear is consistent over time and compares favorably to averages, despite the low TBNs.

Chevron Delo

Chevron Delo 600 ADF is another oil that breaks the traditional additive mold, and it’s fairly new to the market. The 15W/40 and 10W/30 formulations hold the 2^nd and 3^rd place spots for lowest starting TBN in Figure 1, which is surprising, since they’re formulated for diesel engines – diesel oil tends to have more dispersant additive than oil designed for gasoline engines (most of the oils in Figure 1 are gas engine oil). Figure 6 shows the Delo 600’s TBN reaching our “1.0 limit” starting around 9,090 miles. Chevron also had particular goals in mind for this oil – it uses “ultra-low ash additive technology” and is meant for engines with SCR and EGR emissions systems that need to meet state emissions standards.

Figure 6

Figure 6: This oil had an average starting TBN of 4.7. The chart shows the low levels of calcium and magnesium that resulted in fairly low TBNs after typical oil runs for diesel engines.

Since additive packages tend to be proprietary and Chevron never did respond to my email, we can only speculate as to how the elements we find in our testing relate these constraints. Maybe such low calcium and magnesium reflect a reduction in calcium sulfonate and magnesium sulfonate (the compounds that register as calcium and magnesium). While these compounds work well as detergent/dispersants and their alkalinity helps buffer acids, their presence would also boost the sulfur content – a potential problem for emissions goals. But the additive package is unique in other ways too.

Oil report for a virgin sample of Chevron Delo 600 ADF 15W/40

Figure 7

Figure 7 is a virgin sample of Chevron Delo 600 ADF 15W/40. Note the high levels of molybdenum, potassium, and boron, and low levels of phosphorus and zinc, in contrast to the more typical additive package shown in the universal averages column. Moly seems to be providing most of the anti-wear properties that phosphorus and zinc ordinarily would. Potassium is noteworthy and caught our attention right away, since it’s one of two potential markers for anti-freeze.

We’re not certain what additive compound registers as potassium in this oil, but because potassium is alkaline, perhaps it performs some of the same functions calcium sulfonate and magnesium sulfonate do in more traditional additive packages.

Interestingly, even when potassium (and sodium, which is also alkaline) is truly from coolant contamination, it can skew the TBN. Figure 8 is an example of an engine suffering from coolant contamination, which is taking a heavy toll on the bearings and physical properties of the oil. An oil change (and probably major repairs) are needed, yet out of context, the 10.0 TBN looks great. But that doesn’t mean the oil is ready for more use; rather, coolant is skewing the reading. That’s why we never judge a used oil sample by a single data point!

Oil report for a used sample of Valvoline 10W/30

Figure 8

Figure 8 shows a sample of Valvoline 10W/30, which has an average TBN of 7.2 out of the bottle. The oil was used 3,000 miles in an engine with a major coolant problem, seen in very high levels of potassium and sodium, a thick viscosity, high insolubles, and high wear levels. The TBN is very high at 10.0, but that doesn’t mean the oil is ready for more use; rather, coolant is skewing the reading.

As for Chevron 600 ADF? The jury is still out on what kind of results this oil will produce over time, since most of the samples we’ve tested so far are from young engines going through wear-in. It will be interesting to see how these engines mature, but we suspect in the end, this unique oil will perform as well as any other in the most crucial ways: lubricating, cleaning, and cooling engine parts. We’ll just have to give it some special treatment on our end, to avoid false positives for anti-freeze, and avoid putting too much stock in “low” TBNs.

We hope you’re walking away armed with knowledge and a pretty good idea whether adding a TBN or TAN is going to serve your particular aims. If you’re wanting to extend your oil changes, go for it! If you just want a basic assessment of how your engine and oil are holding up, not to worry! We can provide that with the core tests in the standard analysis. Stay tuned for Part 2 next newsletter, where we venture into the lab, and learn about the effects of heat on TBNs and TANs.

By Suzanne Herman|2024-09-19T09:13:00-04:00July 28, 2023|Articles, Gas/Diesel Engine, Lab Tests|Comments Off

Sampling Methods

It’s a perfect spring day. There you are, merrily going about your business of changing the oil. But wait! You forgot the oil sample bottle! A quick scramble to retrieve the bottle gets you back to the oil just as the last of it drains out.

Can you pour a sample out of the filter instead? What if you add a quart a few days before sampling – how does that affect the analysis? What about something like an engine flush – should you use one? Do they work? Your investigative team at Blackstone experimented, and we’ve got answers. While these tests probably won’t qualify for a peer-reviewed journal, they’re a good guide to what you need to know about sampling.

This is part two in our series on sampling methods. Part one, on engine flushes and their effects on analysis, can be found here. Part two covers common sampling scenarios: does it change the results if you take a sample from the filter or dipstick? What if you add fresh oil before sampling? Is it a problem if the oil gets dark right after putting it in the engine? That last question isn’t about sampling methods, but people ask all the time and your investigative team at Blackstone wanted to know, so read on for answers.

Does it matter how you sample?

Our instructions for sampling say to catch a sample as the oil drains from the pan, but that doesn’t always happen. Does it change the date if you take a sample from the filter or pull it through the dipstick?

In short: no. Figures 1 and 2 illustrate three consecutive samples taken from two different cars: Figure 1 is from a Toyota Corolla and Figure 2, a Mercury Milan. The column on the left is a sample taken through the dipstick. The middle column was oil taken while the oil drained from the pan. And the right-hand column is oil taken from the filter.

Results

The samples are unremarkable in that there’s less than 1 ppm difference in the wear metals across all three samples. The sampling method seems to have no impact on the metals that show up in analysis.

The Corolla in Figure 1 does show a higher silicon reading in the sample taken from the oil filter, but perhaps that was due to either dirt collected by the filter that ended up back in suspension in the engine oil, or sample contamination – we did have to use a bit of creativity in removing that filter from the engine, as the filter was overtightened and stuck. (If you’re wondering, we stabbed it with a screwdriver to give us more twisting leverage – we did not sterilize the screwdriver before surgery, so it’s entirely possible some silicon was introduced in that process.)

Does adding fresh oil impact the test results?

It makes sense that that adding fresh oil will dilute the wear numbers. But how much do the numbers change? And does it matter when you add the new oil? In theory, if you have a 4-quart sump, adding one quart of fresh oil shortly before the oil change would mean that your engine’s metals are diluted by 25% from their previous numbers.

To test this theory, Ryan Stark, Blackstone’s president, pulled a sample from his MINI, then added a quart and sampled again to see how the numbers changed.

Crunching numbers

The MINI has a total capacity of 4.5 quarts, so the one quart he added comprised 22% of the total engine oil capacity. Most of the metals decreased by approximately the same percentage: iron dropped from 26 ppm to 20 ppm (a decrease of 23%), copper dropped by 25%, from 8 to 6 ppm. If we assume that chrome actually changed by less than 1 full ppm, due to rounding, the average change in metal works out to around 25%, which is what we’d expect from adding a quart of oil to this engine.

The only other appreciable wear metal in his sample is aluminum, which, interestingly enough, read at 5 ppm in both samples, showing no change at all. We couldn’t let that element go without a little suspicion – why didn’t it change when the other metals did? As it turns out, the actual number our spectrometer reads goes four decimal places to the right. We round to the nearest whole number on the report, but if we pull the full spectral data from those tests, aluminum read at 5.4290, and in the second test aluminum read at 4.8995. Both readings were rounded to 5 ppm in the report, but the full spectral data shows a slight change between the two samples, an improvement of 9.7%. So aluminum did change with the added oil, just not quite as much as the other metals and not enough to show on one of our published reports.

The “when” factor

There are other variables to consider like how far into your oil change you add the oil, and how much oil you add. If a quart of oil is added at the 3,000-mile mark and you run your oil 10,000 total miles, the dilution factor probably is going to be a lot different than adding a quart just before changing the oil. That’s harder to test for because there are too many variables to isolate.

So this isn’t the be-all-end-all of the dilution question, but it at least gives some insight into the fact that the metals could be diluted if you’re adding oil, especially if you’re doing it right before an oil change. It is a good idea to add fresh oil when low, even if you’ll be changing the oil soon. Running an engine on a diminished oil capacity isn’t great.

Why does my used oil look so dark?

We get a lot of questions from people who do an oil change then notice that their oil is dark immediately afterward. Is it a problem?

To get to the bottom of this question, we conducted two oil changes on two separate vehicles, idled the fresh oil for five minutes, then sampled and examined the new oil.

FIG 4: Toyota Corolla – Left, new oil. Middle, oil after 5 minutes. Right, used oil.

FIG 5: Mercury Milan – Left, new oil. Middle, oil after 5 minutes. Right, used oil.

In both cases, the oils were quite dark after just five minutes of use. In Figures 4 and 5, the virgin oil is pretty obvious, but there’s not much difference between the new oil with 5 minutes on it and the oil with several thousand miles on it. In terms of the overall sample color, it’s quite hard to tell.

Results

So does the dark oil indicate anything? Figures 6 and 7 show the analytical results of the new (but darkened) oil after being run 5 minutes in two different engines.

Both oils look very clean in testing, with minimal insolubles, no contamination, and very low metal counts. You might note that the metals do not start at 0 ppm – that’s because you never get 100% of the old oil out when you do an oil change. There’s always some carryover from one oil change to the next, and you can see that in the results.

So is it a problem that the oil looks dark right after an oil change? Nope. It’s fairly normal for oil to darken quickly after an oil change. If anything, it seems to suggest that the oil is doing just what it’s supposed to be doing: collecting contaminants and combustion by-products and keeping them in suspension so they can be removed when the oil is changed.

Sampling Methods: Go for it!

In the end, although we give you guidelines about how to sample, your method really doesn’t make too much difference. If you don’t catch a sample mid-stream, just let us know when you send the oil in and we’ll take that into account when we do the analysis. If anything unusual shows up and we think it might be related to something you did, we’ll let you know in the comments.

By Amanda Callahan|2024-09-19T09:14:05-04:00July 28, 2023|Articles, Gas/Diesel Engine|Comments Off

The Renuzit Experiment

A while back I wrote about buying close to 30 full cans of old oil on eBay, cracking them open, and testing them. It was fun to see what all these old oils looked like, and we ended up learning a lot, but at the end of it all, I had close to 30 Ball jars full of old oil that ended up sitting on the shelf here in the garage, and lingering questions about what to do with it all.

Among the stuff I bought was a gallon can of oil that I never heard of called Renuzit 20W/20. When it first arrived, I was slightly annoyed because the can itself had some rust on the bottom and was seeping oil. However, that turned out to be fortunate because it led me to try an experiment: Can I really run oil this old, and what would happen?

I decided my 1984 Chevy pick-up truck would be a good test bed for this experiment. I have a lot of good base-line data on how it looks. It sees roughly the same type of use year-to-year, and best of all, if the engine exploded, I wouldn’t sue myself for damages.

So on a hot day in August 2012, with the help of my lovely assistant Natalie I actually dumped that stuff in. Was I nervous? You bet! Renuzit doesn’t exactly have a stout additive package, though that didn’t scare me too much. I’ve run oils in this engine that didn’t have any additive at all that we could read.

The viscosity was a little light (in the 20W range), but that didn’t bother me too much either. This engine calls for a 10W/30, and anymore 10W/30 oil looks like 5W/30 after it’s used, and that’s just a few points higher than a 20W anyway.

I guess I was really nervous about destroying my engine. I have rebuilt it in the past, and I know I could do it again, but that doesn’t mean I want to. My wife wouldn’t be too happy about the time away from home and you never know, I might actually need my truck for transportation.

Still, after declaring my intentions to our good customers around the world, I couldn’t back down, so in it went. Upon first start-up I was relieved to see my oil pressure read normally. No funny smells came out of the engine/exhaust, and it seemed to run just fine. So far, so good. And with that, I proceeded to the next part of the test, which is always the hardest, putting miles on the engine.

Adding miles

My truck is basically a backup vehicle, used when I need to haul something or if one of our other vehicles is down, so getting miles on the oil isn’t really all that easy. I live about 1.7 miles from work, so if the weather is nice, I usually ride my bike. On top of that, my daily driver is a MINI convertible, which is about as fun of a car to drive as was ever made. Still, I worked hard and was able to get some miles on my truck.

Right off the bat, I noticed that the engine ran quieter than normal (of course, I also had some muffler work done at the same time, so that may have helped). By November, I was able to get about 400 miles on the engine, so I decided to test the oil (leaving it in use) and see how it was doing.

The test came back showing no trouble at all, so I was happy and started to feel better about this experiment. Winter is a slow time for the truck. It actually lives in my neighbor’s garage and doesn’t see a lot of use. Being a rear-wheel drive pick-up truck, it doesn’t do very well in the ice and snow. Eventually spring came so the truck use started to increase but that’s when tragedy struck!

Sad Mini

My MINI flooded one night while I was in Chicago with some friends. It was a rare occasion that the car actually spent time parked on the street in front of my friend’s house, and it just happened to be the night the north side of Fort Wayne got about six inches of rain in an hour. The street turned into a lake and my car went for a swim.

The bright side

The good news is that my truck was still running well and, being promoted to daily driver, I was going to start putting a lot of miles on it. Over the summer and into the fall I was able to accumulate almost 2,000 miles which is still short of 2,500-mile double-money back guarantee that the Renuzit can advertised, but a long run for my truck.

In fact, I was thinking about running the oil longer, but it was close to the “Add” mark on the dipstick, and not having any more of this oil, I decided to just go ahead and change it. A sample was taken (of course) and the results aren’t any better or worse that what I’ve received in the past.

So there you have it — an ancient oil run in a fairly modern engine, and no harm done. Would I run it again? Sure thing, except it goes against my principle of not paying any more than I have to for an oil change. That stuff was $75 for 5 quarts, plus $25 for shipping and that’s not in my budget, even if I could find it again. Still, this was a fun experiment, and since Blackstone still had a lot of old oil leftover from the eBay purchases, I decided to run those. Besides, it’s canning season and I need the jars.

By Ryan Stark|2024-09-19T09:16:55-04:00July 28, 2023|Articles, Gas/Diesel Engine|Comments Off

The Lower Unit Blues

I wouldn’t consider myself a nautical man, though growing up fairly close to a lot of really nice lakes, I was able to go fishing, tubing, and water skiing every now and then. These are all things I still enjoy though this type of hobby generally requires a boat. My grandfather gave me a fishing boat many years ago and while that doesn’t need much maintenance, I do use my step-mother Kathy’s boat once or twice a summer and that’s a different story.

The boat & its lower unit

The boat is a 1994 Starcraft 1700 with a 90 HP Mercury 2-stroke engine. It’s large enough to carry six people comfortably and pull a tube around the lake. She bought the boat used in 2016 and it had obviously not seen a whole lot use or maintenance in the preceding years, so I decided to help out with what little maintenance I could, which basically involved changing the oil in the lower unit.

Now for those of you who are even less nautical than me, the lower unit is a gear box that transmits power from the engine to the propeller. Technically, it can be called a transmission, but that doesn’t really apply because it only has two gears—forward and reverse—and there isn’t any sort of complicated clutching system involved to change the gears. It’s basically a gear box, which tends to be extremely reliable and would have a super long life if it wasn’t for the environment in which it has to operate—underwater.

The water blues

As you might have guessed, water contamination is a major problem with these units and when I changed the oil in Kathy’s boat, I could tell that water was getting in.

Now, you don’t have to have worked at an oil lab for 20+ years to know what serious water contamination looks like. Think milkshake, with the main color being whatever the color of the oil was to start with. When an oil with red dye gets water in it, it tends to look like strawberry milkshake. If the oil starts out blue, you end up with a blueberry milkshake. Start with brown oil and you get chocolate.

So the very first time I changed it, I grabbed a sample as the oil was draining out to see how bad the water contamination was (see Figure 1).

Oil from the lower unit, showing a clear separation between the oil and a layer of water contamination

Figure 1: Not good

Here at the lab, even though an oil might obviously have water in it, we don’t just use the color to make that call; we use an actual ASTM method to identify water. The test is called the “crackle test.”

For that, you drop a small amount of oil onto something hot (400°F) like a brass cup, and if the oil sizzles/crackles, then yes you have water. (We get the percentage from the insolubles test but that’s another matter.) If you are crunched for time and can’t send your oil in to us, you can actually do this test at home in your kitchen using an old pan. Just don’t cook up a batch of eggs on it afterwards.

The good thing about lower units is, if you keep the oil changed and no water is getting in, they will last for a very long time. And if water is getting in, frequent oil changes will keep any damage to a minimum. However, if you neglect one that does have water leaking in, the water will cause the steel parts to rust and that will allow for all kinds of bad things to happen. In my situation, I knew the lower unit in Kathy’s boat was letting water in and that something should have been done about it, but life got in the way.

Live & learn (and hopefully don’t wreck)

So this year, when I went to try to put it in the lake I got quite the surprise when I found it the motor would not shift out of forward. Of course, I didn’t know this until I was trying to back the boat away from the boat trailer at the ramp. Needless to say, I was very confused as to why the boat was going forward when I had it in reverse, and Kathy was even more confused (and profane) when she thought the boat was going to end up in the bed of her truck. I did start the engine prior to heading to the lake and it was running like a champ. I just didn’t think to check to see if the motor would go into reverse, or even shift at all. Live and learn.

So now the lower unit is in a partial state of disassembly in my garage, and let me tell you—nothing is a sadder sight in the middle of boating season. I find myself struggling with shame and regret about not having changed oil in it sooner, or better yet, just fixed the seal that was letting water in in the first place. My only hope is that you don’t let the same thing happen to you. Change that lower unit oil and sleep easy at night. Meanwhile, I’ll be learning the real meaning of the word boat – Bust Out Another Thousand!

By Ryan Stark|2024-06-04T14:55:42-04:00July 28, 2023|Articles, Marine|Comments Off

How Often Should You Change Your Oil?

Change is inevitable, right? But not as inevitable as it used to be, at least for your engine oil. When it comes to the questions we get every day, right up there with “What kind of oil should I use?” is “How often should I change my oil?” Happily, the answer for most people is: Not as often as you used to.

What other people will tell you

Back in the day, everyone knew you changed your oil at 3,000 miles or three months, whichever comes first. Wait, did I say back in the day? Lots of places still tell you that’s how often to change it, and not surprisingly, the places you’re hearing this are oil change places that make money from you coming in regularly. We’re here to help cut through the noise, and hopefully you’ll believe us because hey, we’ve got science on our side. The answer to how often you need to change your oil is: It’s different for everybody.

Owner’s manual

Most cars and trucks (motorcycles, boats, etc.) have guidelines listed in the owner’s manual that outline certain driving conditions and how often to change the oil.

The problem is, sometimes the conditions they outline as “severe” are laughable. We’ve seen manuals that say if you’re doing primarily city driving, that’s severe. Call me silly, but I’d say “severe” should count as something that’s out of the ordinary for most people. Most people drive to work and back. Most people drive to the store, go to school, take the kids to school, whatever.

Severe operation, on the other hand, could legitimately be something like lots of operation on dusty roads, towing constantly, driving really fast in a really hot or really cold place, or driving up and down mountain passes. Under these conditions, we could see needing to change the oil more often. But again, it really is a case-by-case thing. City driving for me, in Fort Wayne, Indiana, is different from city driving in LA.

The point is, despite the best intentions of the people who write the guidelines, how often you should change your oil really depends on you, your engine, how you drive, and where you drive. One caveat: As long as your engine is under warranty, you should change however often the manufacturer says to. That way if something goes wrong, they can’t blame you for lack of maintenance.

OLM

Most new engines also come with an oil life monitor to tell you when to change the oil. This is a good system, and even if it’s not 100% accurate all the time, it’s better than the 3,000 miles or three months system.

Different oil life monitors take different things into account. We’ve been told that certain German automakers changed from basing theirs on variables such as cold starts and RPMs to basically counting down the amount of fuel used. Some have a sensor in the oil that estimates particulates in the oil. Some monitors seem to give better recommendations the longer you use them. All this is fine and it’s better than nothing, but there’s also oil analysis. Guess which method we like best for determining how often you should change the oil?

What we look at

When you send in a sample, we ask on the oil slip if you’re interested in extended oil use. What we want to know is, do you want to run your oil longer than you currently are? We have found that people are often changing their oil too soon. As you know there is not one oil-change interval that’s perfect for everyone, so what do we take into account when we do recommend longer oil changes?

Metal

If you’ve seen our report, you know that we keep a database of all different engine types. We average their wear and then compare that to your sample to see what’s reading high, what’s normal, and what’s better than most. We like it when you send along notes. The more you tell us about how you’re driving or any specific conditions that might affect the sample, the better the recommendation we can give you.

If wear is above average, we always look for reasons that might explain why. For example, say your metals are generally higher than average but you’re also running your oil longer than average. We take that into account and give you an estimate on how much longer we think you can go for the next oil change.

We don’t like to take too big of a leap. We wouldn’t, for example, tell you to go from 5,000 to 10,000 miles because you might send in a 10,000-mile sample and have lots of wear, and we wouldn’t know where the tipping point was. But we might tell you to go 7,500 miles next, and if things look good at that point, to go longer after that.

Some people automatically think having more wear than average is bad, but that’s not necessarily so. If there’s a good reason for the wear, and if there’s not so much metal that it’s making the oil itself abrasive, we’re happy to let a little extra metal ride. The question is, are you okay with it? In the end our recommendation is just our opinion, and you should do whatever you’re comfortable with.

Sometimes we suspect a problem and we’ll recommend a shorter oil change. Obviously shorter oil changes don’t fix a problem if one exists, but they do let you monitor the problem more closely and get the extra metal out of the system. Once a lot of wear builds up, the oil itself can become abrasive, which causes even more wear. It’s a cycle to avoid.

Contamination

We also look at any contamination that might be present in the oil. Obviously no contamination is the best, but your engine can tolerate small amounts of fuel and (sometimes) moisture without it being a serious problem.

Fuel is actually a very common contaminant. It mainly comes from normal operation and idling, and as long as it’s not causing any wear problems, we usually would recommend a longer oil run even with fuel present. But if fuel persists or the trend is one of increasing fuel with each oil change, we’d probably recommend cutting back on your oil changes for the reasons outlined above.

We don’t see water very often because modern engines are closed up tight. But we do see antifreeze, and when it’s present we almost always recommend changing the oil more often. Antifreeze destroys the oil’s ability to lubricate parts, which is why it starts causing poor wear so soon (usually bearing wear).

We also look at how oxidized the oil is with the insolubles test. Oil oxidation happens normally and for the most part, your oil filter removes the oxidized solids from the system just fine.

Occasionally something (excessive heat, contamination) causes the oil to oxidize faster than usual and the oil filter can’t keep up. In this case we would also recommend a shorter oil change, at least until you can figure out why it’s happening.

The insolubles test also helps us determine soot problems for diesel engines. If soot is excessive but everything else looks okay, we might suggest trying a longer run. Or if there is ring wear and other signs of poor combustion, we would probably tell you to cut back.

Operation

How you drive is another factor we take into account when we suggest your next oil change interval. If you and I both have the exact same Subaru engine except you go to the track regularly and all I do is drive to work and the store, then you might get a different recommendation than me. Or maybe you won’t — if your engine looks good and it’s faring well under the racing conditions, we might be running the same oil changes.

Or, if someone tells us their commute is a long highway drive every day, that person may be able to go a lot longer on their oil than someone with the same engine who drives two miles each way to work and back every day. It’s all in the numbers. The numbers don’t lie!

What about the oil?

Notice what we have not said we take into account: the brand you’re using and whether it’s synthetic or petroleum oil. When Jim started this company back in 1985 he came up with a line he liked to use: Oil is oil. We still stand by that today. The oil guys would have you believe otherwise, but brand really does not seem to make a difference in how your engine wears, or how often you can change your oil.

Well, okay, if you were using some guy’s oil that he “recycled” in the back of his garage from emptied-out oil pans that he filtered with a piece of cheesecloth, we might say in that case brand does matter. But as long as you’re using an API-certified oil, your engine probably isn’t going to care what you use. We like synthetics and we like conventional oil. In the end, what you use and how often you change your oil is completely your choice. We’ll give you our recommendation and you can do whatever you want with it. If you want to run longer on the oil despite having high wear, that’s totally fine. And if you have great numbers and you like changing at 3,000 miles, that’s perfectly fine too. It’s your engine, your money, and your life: change it when you want!

By Ryan Stark|2024-09-19T09:19:01-04:00July 28, 2023|Articles, Gas/Diesel Engine, Marine|Comments Off