The CamGuard Chronicles

By Mike Busch

Reprinted from the Cessna Pilots Association -November 2008

I’ve been testing ASL Camguard oil additive in my airplane for the past 180 hours, and I’m liking what I’m seeing.

In the nearly two decades that I’ve been a tech rep and columnist for CPA—gawd, has it really been that long? I’ve been a staunch skeptic when it comes to aftermarket oil additives, and often referred to them sarcastically as “miracles-in-a-can.” Over the years, I’ve looked at independent tests on various additives including AvBlend and Microlon, but I’ve never seen a shred of evidence that they offer any benefit. This always struck me as unremarkable, because I figured that if an oil additive was actually demonstrably beneficial, Aeroshell, Exxon and Phillips would already be blending it into its aviation oils.

A few years ago, I started hearing about yet another miracle-in-a-can called ASL Camguard. I naturally assumed that it was just one more alchemical admixture of snake oil, food coloring and perfume designed to separate aircraft owners from their hard-earned cash.

Then a funny thing happened: The developer of ASL Camguard showed up on the CPA Forums. His name is Ed Kollin, and the more of his posts I read, the more I thought to myself, “Gee, this guy really sounds like he knows what he’s talking about!” I did a little Googling and discovered that Ed was a research chemist who previously worked for Exxon Research & Engineering as director of its engine laboratory. I couldn’t help thinking that this didn’t sound like the resume of your typical snake-oil salesman, and started wondering whether perhaps ASL Camguard might be an exception to the rule.

So at EAA AirVenture 2007, I made a point of finding Ed Kollin at the ASL Camguard booth, and I spent nearly a halfhour grilling him about his product. It was a fascinating conversation.

The way Ed tells the story, he was working at the engine lab at Exxon Research when Exxon decided to come out with an advanced-technology aviation oil. Ed was tasked to develop an initial formulation. After much research, he developed an additive package that he believed would perform head and shoulders above the competition. Then, much to his disappointment, Exxon decided (according to Ed) to take a more conventional route. Ed subsequently left Exxon and over the next year developed a “no compromises” additive package as an aftermarket product called ASL Camguard.

After talking to Ed, I was sufficiently impressed that I flew home from Oshkosh with a case of ASL Camguard in the baggage compartment of my 1979 Cessna T310R, and decided to give it a try. My intention was to use it for 100 hours and see what impact (if any) it had on my oil analysis results.

Shortly after my return from Oshkosh, I did an oil change on both engines and added a pint of Camguard to each for the first time. After 83 hours, the oil analysis results were promising.
But I considered them somewhat inconclusive, so I decided to continue using ASL Camguard for awhile longer. As I write this column, I’ve been using Camguard for 180 hours, and I now think have data sufficiently interesting that I wanted to share it with CPA members.

Why Camguard?

Novtechtopicsrev2-2My interest in Camguard stems from my long-held belief that by far the major threat to piston engine longevity in ownerflown airplanes is not wear but corrosion. I’ve amassed a great deal of evidence showing that it’s damn near impossible for us to wear out these engines, because they’re incredibly robust. I’ve made no secret of the fact that my own engines are now 1,000 hours past TBO and doing great, and it wouldn’t astonish me to see them reach 3,000 hours or more before needing any sort of teardown, at least if present trends continue.

If they don’t make the distance, it won’t be because I wore them out; it’ll be because I allowed them to corrode internally because I wasn’t flying them often or regularly enough. Let me show you what I mean.

About five and a half years ago, I developed a very serious health problem that put me out of action for many months and actually landed me in intensive care for awhile. During that scary episode in my life, my 1979 Cessna T310R sat unflown in its hangar for about four months. My oil analysis (figure 1) clearly shows the toll this took on the engines.

While I normally fly the airplane 150 to 250 hours a year, you can see that between March and October 2002, the airplane only flew 17 hours in a period of 7½ months. Not good. You can also see that as a result of that inactivity, the normalized quantity of iron in the oil (measured in parts per million per hour) doubled from the normal values during the preceding and succeeding periods of normal activity. A graph of this data (figure 2) makes this even more obvious.


Look how clearly iron production -rust, actually correlates with lack of activity. Irregular usage is simply a fact of life for most owner-flown airplanes. Mine is a perfect example. While I fly more hours a year than the average owner, my usage tends to be in fits and starts. One month I’ll put 30 hours on the airplane. The next month, it’s a hangar queen. This is clearly not good for the engines, but as Walter Cronkite used to say, that’s the way it is. There’s not much I can do about it.

Or is there? Ed Kollin claimed that he developed ASL Camguard specifically to address the problem of corrosion during periods of engine disuse. The question is: Does it actually work? After talking to Ed at AirVenture 2007, I decided to find out for myself.

So how’d it do?

I started using Camguard in my engines at the beginning of August 2007, adding one pint to 10 quarts of the Aeroshell W100 that I’ve used in these engines for decades. I’ve now
flown 180 hours with the stuff, and done four oil changes and oil analysis samples during a period of just over a year. I compared the normalized wear metals for three oil change intervals before starting Camguard with three oil change intervals after starting Camguard (leaving out the last non-Camguard and the first Camguard intervals to eliminate transition effects). Here are the results in figure 3.


As you can see, there was a modest decrease of all major wear metals both engines, with the sole exception of nickel which increased slightly on the left engine. It seems to me that such a decrease in wear metals, even though relatively modest, easily justifies the cost of using Camguard.

Wait! It gets better!

What I find even more significant, however, is the evidence that Camguard is clearly doing a spectacular job of reducing corrosion damage during periods of disuse. How do I know that? Watch closely, because this gets interesting.

Over the more than two decades that I’ve owned my T310R (and done regular oil analysis on it), I’ve noticed a fascinating seasonal pattern to the levels of iron in the oil. Specifically, the first oil change I do after April of each year shows a significant spike in iron compared with other samples throughout the year. There’s a very good reason for this. Every year, I down the airplane sometime in March for its annual inspection. Because a T310R is a fairly complex beast, and because I do all the work on it myself, and because I’m probably the world’s slowest mechanic, the airplane is always down for at least a month and sometimes a month and a half before I get it put back together again. This prolonged annual ordeal is usually the longest period of inactivity that the airplane has all year, and the iron levels in the oil reflect this clearly (fig. 4).


The left engine normally makes between .6 and .8 ppm/hr of iron, except for the first oil change after each annual inspection where it makes more than 1.1 ppm/hr. Similarly, the right engine (which has always produced higher wear metals than the left one for more than 4,000 hours and I don’t know why) usually makes between .8 and 1.1 ppm/hr, except for the first oil change after each annual where it makes 1.2 to 1.5 ppm/hr.

[Note that the unusually high number of 1.8 ppm/hr right after the 2007 annual was due to the fact that I changed a cylinder, and breaking it in generated even higher iron than normal.]

Ah, but look at the post-2008-annual numbers—the first such results since I started using Camguard. The iron numbers for those samples not only did NOT spike up (as they always had before), but actually were BELOW AVERAGE for each respective engine! To me, this is a very significant change from the long established pattern of annual iron spikes after annual inspections, and convinces me that Camguard is doing a very effective job of corrosion protection.

I’ll know more a year from now when I have another set of post-annual-inspection oil report, but for now this is what I’m seeing and I’m frankly impressed. Time to order another case of Camguard!

Tech Topics is a monthly column written by Mike Busch of CPA’s technical staff. Mike is a longtime CPA Magazine columnist, co-founder of AVweb and teaches Savvy Seminars,, for aircraft owners and mechanics. Mike is the 2008 AMT of the year. Mike owns, flies and maintains a 1979 Cessna T310R based in Santa Maria, California.