About Ryan Stark

Ryan started at Blackstone in 1997 after graduating from Purdue University with a degree in mechanical engineering. Ryan is responsible for writing and maintaining Blackstone's software program, setting up and managing the lab, writing reports, and a million other things that need to be done in a business. When he's not kicking ass in the lab or writing code, Ryan enjoys putting his pilot's license to good use, working on his '84 Chevy 3/4 ton, and raising his kids. As an experiment, Ryan ran Aeroshell W65 — an oil with no zinc or phosphorus in it — in his Chevy to determine if the hype over ZDDP (zinc dithiophosphate) is all that or not, figuring if the experiment ruined his engine, well, he's rebuilt it before. (Spoiler alert: The engine was fine. To read about the endeavor and see pictures from the rebuild, read the article "Rebuilding a GM 350 Engine.")

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

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

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

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

Rebuilding a GM 350 Engine

This is a story of my first complete rebuilding an engine. The engine is a GM 350 V-8 out of a 1984 Chevy Custom Deluxe pickup truck. The truck was custom in that I’m fairly sure no other truck is rusted in exactly the same way, and deluxe in that both windows still roll down.

I purchased this truck in 1999, and one of the sales points of the truck was the engine. It started up and ran well, though it had a super high idle that did not want to drop down after the engine warmed up. The vehicle doesn’t have an RPM gauge so I can’t say exactly how high it was, though it was so fast that I did not need to step on the accelerator after a stop light and it would get up to about 35 MPH on its own. I figured this was a carburetor problem and could be addressed later.

I was in love with the truck and had to have it. I didn’t even bother to do an oil analysis on it before I bought it, partly because I felt I could fix anything that went wrong and partly because I was scared at what I would find.

After pulling the first sample, I was glad I hadn’t seen it before I bought it. This engine had clearly been used and abused, which was to be expected for a former work truck with over 160,000 miles on it. (See Report #1 B30210.) I felt that if I changed oil several times over the next few thousand miles, I would be able to clean the engine up and hopefully get another 100,000 miles out of it.

This truck was not my daily driver, so the high idle problem and poor wear weren’t too big of a concern. After about two years, I pulled the original carburetor and had it rebuilt by a shop. This seemed to help for about 500 miles, and but then the high idle came back. I was also finding a lot of fuel dilution in the oil. I attributed the idle and fuel to a poor rebuild of the carburetor and my fix was to curse the guy who did the work. This didn’t help the problem, though the truck always started when I needed it, so I didn’t feel the need to try and fix it again.

Smoke on start-up

Eventually the day came when I started seeing some smoke on start-up. At first it wasn’t too bad, just a little for about a minute, but then it stared getting worse — bad enough that the smoke killed all of the mosquitoes in a two-block radius. I was told that replacing the valve seals should fix this, so I decided to take the truck out to my Dad’s barn in Ossian and tear into it.

Ossian is a little town abut 15 miles south of Fort Wayne, and among its many charms is its zip code: 46777. Maybe their town slogan should be “Get Lucky in Ossian!” Or maybe not. Anyway, Dad’s barn wasn’t the best place for engine work, mostly because it didn’t have any doors, had a dirt floor, poor lighting, and birds lived everywhere, but it was better than working on the street.

I dug into the engine hoping that I would just be able to remove the heads, get them cleaned up, replace the carburetor and we’d be back on the road. Unfortunately, when I removed the valve covers, that’s when I ran into my first problem: sludge! Not just a little hidden in the nooks and crannies of the head, but large chunks the size of a golf ball. (See figure 1 and C27858.) This was my first sign that the engine might need a little more love than I have figured on.

After removing the oil pan and finding some scored bearings, I decided to pull the whole engine and do a complete rebuild. So I borrowed an engine puller, got the engine loose, and hooked up the chains, and ran that’s when I ran into my second problem. The puller I borrowed was made for a car and I could not clear the radiator, even after jacking up the puller as far as it would go.

Removing the engine

To get the engine out, we had to lower it onto some wood blocks and hook one removable chain link from the puller arm to the webbing between the holds of the carburetor intake. This was a dicey maneuver to say the least, but it worked. I was originally thinking about swapping out the steel intake manifold for an aluminum one, but after seeing the strength of the original steel one, I was too impressed to scrap it.

Once we got the engine out, I commenced to pull it apart. I got the major parts cleaned, replaced the bearings, painted it up nice, and put it all back together. It took about a month and it was late October, but I finally had it all back together and looking pretty.

I used the same method to get the engine back into the truck. All the necessary parts went back on and I eventually got to the point at which I was ready to start it up. At the much-anticipated turning of the key, I ran into the third problem: nothing happened. Sure, the starter was trying to turn the engine over, but the engine itself was locked up solid. After some discussion, we decided I may have mixed up the order of the rod-end caps, and this acted like a clamp around the crankshaft and prevented it from turning. In hindsight, I guess I should have realized something was wrong when the engine was out and it took a crowbar on the flywheel to make it turn so I could adjust the valves, but hey, that’s hindsight, and I was a rookie.

Well, it being late October in Northern Indiana in an open barn with no heat, I didn’t really look forward to the prospect of pulling the engine out again, doing another rebuild, and then putting it all back together. Fortunately, we had just bought a new building for Blackstone to move into. It was a construction building in its previous life that had a nice big garage, a chain hoist, and a heated workshop. So we loaded the Custom Deluxe onto a flatbed and had it taken to the new building.

After a few months of off-and-on work, I had the engine back in place and ready to start up. This time it cranked over just fine and eventually started with some timing adjustments and only a little eyebrow hair burned off during a backfire.

The first few oil reports weren’t pretty, but it’s been 8,000 miles and five years since the rebuild and I’m happy to say it’s still running well. It’s still not wearing as well as I would like, but the truck doesn’t see a lot of use, so I blame that on corrosion due to inactivity. The fuel dilution is pretty much gone and I don’t get any smoke on start-up, so all in all it was a successful job.

Now that the engine is pretty much past wear-in, I’ve decided to start experimenting with it. There has been a lot of talk lately about the importance of zinc in an engine. All gasoline engines oils have an additive called zinc dithiophosphate. It’s an anti-wear additive and is normally present at a level between 500 ppm and 1,000 ppm. Apparently, newer gasoline engine oils are dropping their zinc level and this is causing cam failures in flat-tappet engines. Being a bit of a skeptic, I’m not sure this is the case, so I’ve decided to use my freshly overhauled flat-tappet GM 350 as a test bed. Stay tuned for the next newsletter as I try running Aeroshell W65 in it — an oil that doesn’t have any zinc additive it in at all.

I’d like to thank Jim Stark (my Dad) for letting me use his barn and all the help he gave me during the process. Also C&P Machine shop for letting me know which rod end cap went to which rod (very important). And also my wife, for not throwing me out during this project.

By Ryan Stark|2024-09-19T09:20:45-04:00July 28, 2023|Articles, Gas/Diesel Engine|Comments Off

How Often Should I Sample?

One of the most common questions we get asked is, “How often should I send in a sample?” and this is one that I tend to struggle with answering.

The businessman in me says at every oil change regardless, and while you’re at it, check your transmission fluid, differential fluid, and your wife’s/husband’s car. And don’t forget any air compressors, lawn mowers, wood splitters, etc. you may own. And your neighbor’s car was smoking a bit last time you saw it drive past, better check that too.

Unfortunately, before I start talking, my “realist” side kicks in and I usually say something like once a year, after you have some good trends established. But even that answer doesn’t always apply. What if you don’t drive your vehicle very often, or at all? Is it really necessary to test the oil once a year? The answer to that is once again not really. Though if you think you might have a problem developing, then it could be a good idea to sample more often than you normally would.

Old oil

We recently had a customer send in a sample of oil that was in an engine for 10 years and had not been run at all in more than 5 years — and amazingly enough wear metals were virtually identical to what we were seeing when he last sampled 10 years ago.

The only significant difference was at insolubles. These had gone from 0.2% to 0.0% after the 5 years of sitting. We figured the reason for this was gravity. All normal engine oils contain dispersant additives, and their function is to hold dirt and solids in suspension so they can be filtered out. Do they work? Absolutely, but asking them to work for a full five years is a little much. The good news is that the additives are still in the oil, so once the engine starts up and sees some use, those solids should be picked up and dispersed again.

So, if we can say with good certainty that the oil itself won’t go bad just sitting in an engine, you might wonder why it needs to be changed at all? The answer to that is contamination.

Contamination problems

Engine oil has maybe the hardest life of any oil application out there. Not only does it see frequent temperature swings of 150° to 200°F (65° to 90°C), but it will also get contaminated with fuel blow-by and a little atmospheric water as well.

Ideally the fuel and water will boil out once the oil gets up to operating temperature, but that contamination will add up over time and eventually cause the oil to start to oxidize. If you can pinpoint exactly when the oil will oxidize enough that it will start to affect wear or cause the oil’s viscosity to change, that’s the point at which you want to change the oil. If you test your oil on a regular basis, you can start to identify that point and that’s one of the reasons why we’re here.

So when is the best time to get a sample? The answer to that is: it depends.

Best time to sample?

If you just bought a brand-new car, the first oil is factory oil and while that oil will sometimes have an unusual additive package, it’s not that useful for finding a problem, or developing a normal wear trend.

Factory oil is typically loaded with excess metal from wear-in of new parts as well and some silicon from sealers used when the engine was assembled, and this stuff normally takes two or three oil changes to wash out.

So, while these samples aren’t useful as far as trends go, they are useful in finding problems in engines that have been recently rebuilt or had other major work done, and we always recommend testing those from the beginning. This is because if wear metals don’t drop from that initial oil fill, it can be the early indication of a problem.

It’s always a good idea to get a trend going while the engine is running well. A trend consists of three samples. Once we have that established and the engine is running perfectly, then it’s not really necessary to get a sample at each oil change and at that point it’s okay in most cases to go to a once-a-year sampling routine.

Once a year?

You might be wondering why once a year? The reason for that is two-fold. One: A lot of people (including myself) only change their oil once a year. It’s also the only time I crawl under my car and have the hood open. I consider it like an annual inspection and there are been numerous times that I have been on my back waiting for the oil to drain when I noticed another problem like a seeping freeze-plug or a torn CV boot. Two: It’s easy to remember.

However, the once-a-year rule doesn’t always apply. There are many vehicles out there that only see light use (maybe less than 500 miles a year), so not only can they typically skip changing oil on a yearly basis, then don’t need to sample every year.

Another factor is how important the vehicle is to you. If you rely on it for your business, or it’s the only vehicle you have and it’s getting up there in mileage, then sampling at every oil change might be a very good idea.

Engines speak before they fail

We can see problems developing in your engine long before they actually cause a failure, so you normally have some time to do something about any trouble we might spot. Still, like a lot of things in life, the earlier you know about problems the better.

We get as lot of samples from engines that have a known problem, so we test the oil and usually see poor wear, but telling how bad the problem is or how/when it started is hard without trends from when the engine was normal. We do have averages that give us a good idea how an engine should look overall, but they aren’t as valuable as trends when it comes to saying exactly what’s normal for a particular engine and the use it sees.

So there you have it, I’m actually saying you may not need our services as much as you might think. Some of the other business owners out there might call me crazy and I guess they’re right. But please, feel free to sample anytime you like. As you know there is nothing better than getting a glowing oil report on your pride and joy.

By Ryan Stark|2024-09-19T09:34:43-04:00July 28, 2023|Articles, Gas/Diesel Engine, Marine|Comments Off

Viscosity: Going Down!

April of 2017 will mark my 20^th year here at Blackstone and in that time a lot of changes have taken place. I’m a big fan of change myself and long ago got some advice from my Uncle Dan who said, “The only thing that’s constant in life is change.” I decided that his words were the truth, and it seems to me like change should be embraced because there is no stopping it, and also for the most part change is good. It might not seem good on the outset, but if you give it some time, things eventually work out. After a bit of reflection on the changes in the oil industry, I’ve decided that one of the best ones has been the trend to lower viscosity oils.

The thin oil trend

I started changing my own oil on a regular basis in the early ’90s, and at that time 10W/30 was the oil of choice in my 1981 Chevy Citation. I didn’t think that much about it. It said right on the oil cap use 10W/30, so I bought whatever was on sale and went along fat, dumb, and happy.

At that time 5W/30 oil was starting to be as common as 10W/30 on the shelves, but I never went with it because it wasn’t what GM said to use. However, my wife’s first car (1994 Buick Skylark) recommended 5W/30, so that was a sign that thinner oils were starting to come into favor. Again, I didn’t think much about it, and basically just stuck with what was recommended when I changed her oil.

Then, in the early 2000s I noticed that we were starting to see a lot of samples from Ford V-8 engines that were running 5W/20 oil. This was a bit of a surprise since that’s pretty thin oil, but it was hard to argue with the results. Those engines produced some of the best wear we would see on a regular basis, so it quickly because obvious to me that this was a change for the better. And if you think about it, it makes sense.

Wear at start-up

For years, it was taken as fact by a lot of people that most of the wear in an engine happens at start-up. Now I haven’t done any studies myself to see if that was true, but that statement didn’t seem out of line from what I know about engines.

So assuming it’s true, why would just starting an engine cause wear? Well, I believe the answer is the oil isn’t flowing over all of the parts like it does shortly after start-up. I do know that engines have virtually no metals parts touching one another without a thin film of oil providing a lubrication barrier, at least once oil pressure has been established. I also know that thin oil pumps easier than thick oil, so it’s seems obvious that the quicker you can get the oil to the parts, the less wear an engine will produce. From then on I was sold on thin oil.

So what’s the problem here? Well, when I first started at Blackstone, I was told that thick oil is good for the bearings, and I didn’t have cause to doubt that statement until I saw these Ford V-8s producing virtually no wear, and I knew some of them were work trucks that were hauling heavy loads. So could it be that the bearings didn’t need thin oil to survive? The answer is a resounding yes.

Even for diesels?

That trend toward thinner oil has proven true everywhere except for diesel engines. For years and years and even today, the oil of choice in a diesel was/is 15W/40. But, if a heavy-duty gas engine can run light oil, why can’t a diesel?

We would occasionally see diesel samples from Alaska that were running 5W/30 and they would look fine, so why not use it down here in the lower 48? In colder weather, it was acceptable for diesel to run thin oil, but that really only matters on start-up. But the oil doesn’t get thicker as it heats up¾it thins out.

So could it be that thin oil does fine even when it get gets up to operating temperature? The answer to me was another resounding yes, and I wondered when the day would come that 15W/40 would not longer be the manufacturer’s choice foe diesel engines. Well, that change has come!

Today we are starting to see more diesel fleets going to 10W/30, and I’m here to tell you that this change is good. Not only will the bearings do just fine, but the engines will start up better (especially in the cold). Now, there will always be some people who are resistant to change. In fact that are whole countries that are. The German vehicle manufacturers have yet to embrace thin oil, though I think that change will happen someday.

Yes, change is good and I have yet to see a change happen that leaves hundreds of thousands vehicles stuck along the side of the road. The sulfur has been virtually removed from diesel fuel and your old tractor still runs fine* (if this statement makes you mad, see my note below). Additive levels have been lowered in engine oil and the old flat-tappet engines still run great. And now thinner oils are here to stay. I’m excited to see what the changes the next 20 years might bring and I believe that I’ll embrace it, unless it involves getting rid of oil altogether!

*Note: Don’t get mad at me. I wasn’t in charge of that change and your injectors/fuel pump were probably on their way out anyway!

By Ryan Stark|2024-09-19T09:35:43-04:00July 28, 2023|Articles, Gas/Diesel Engine, Lab Tests|Comments Off