Think about it: 40 times a second, an aircraft piston rockets to the top of the cylinder, stops dead in a couple of nanoseconds, reverses direction and plummets to the bottom of the jug, all the while trying to stretch the connecting rod like a piece of warm taffy and exerting enough smash on the bearings to reduce them to oily Babbitt pulp.
Or maybe its better not to think about it. Which is precisely why it makes sense to send oil samples to an analytical lab and have them look for signs of impending doom. Oil analysis has been available in the GA piston-engine market for years and there are plenty of labs to pick from.
But pick one you must. With that in mind, we decided to compare the prices and services offered by various SOAP (spectrometric oil analysis program) labs with an eye toward the best value and service. Are all these labs providing the same basic service or are there standouts?
Were not sure our little test program reveals a clear winner but we found the exercise interesting, nonetheless. We do think some labs deliver better value than others.
Okay, We Cheated
Ever confident in the sanctity of modern analytical science, we carefully drained five samples from our Mooneys mid-time Lycoming IO-360 and sent them off to five labs. We reasoned that the same sample ought to return similar if not identical results. We reasoned wrong, as it turned out.
Also, our sampling included ummm…a slight chain of custody problem, in that a second set of samples we sent to the labs contained oil from our frequently flown 1996 Nissan pick-up truck.
Okay, so were stinkers, the journalistic equivalents of the spitball-throwing malcontents at the back of the classroom. But really, we wanted to see if anyone would notice the difference between Quaker State and Phillips XC. (Only one lab did, although two others had their suspicions.) Our criteria are simple: For what were paying for analysis, how easy does the lab make it to pull and send a sample, how quickly do they burn it and interpret the data and how do they notify you? Simple.
Rather than cover the waterfront, we chose five labs which we either know about or which advertise heavily. These include Spectro in Arlington, Texas, Aviation Oil Analysis in Phoenix, Arizona (marketed through Aircraft Spruce) Engine Oil Analysis in Tulsa, Oklahoma, Aviation Laboratories in Kenner, Louisiana (marketed by Sportys and AOPA) and AeroShell Care/Analysts, Inc., a contract lab which does business under the Shell flag.
Some notes on price, sales and sample methods: The general standard in the industry is pre-payment for a sample bottle and form, which also covers the cost of the analysis. As shown in the chart below, prices for these kits vary between $11.90 pre-paid and $22.95. Some labs will send the sampling kit for free, then expect payment by check when the oil arrives for analysis.
All of them include a self-mailer of some kind, either an envelope or box or, in the case of AOA, a bottle within a bottle, with the larger bottle serving as the shipping container. One thing we think is important to avoid errors is that the bottle have its own label, identifying at least the aircraft N-number, if not the engine serial number.
Only two labs provide no bottle label at all; Aviation Oil Analysis and Aviation Labs. This is a minor complaint but it saves hunting down a magic marker to label the sample.
Aviation Laboratories is the most expensive of the lot if bought through Sportys and really ought to bother with a bottle label, in our estimation. On the other hand, for $11 more than the cheapest alternative, Aviation Labs sends a two-foot length of heavy wall plastic tubing which we surmise is supposed to help extract a sample. (Were not sure how, since no instructions were included and the usual sample withdrawal method is via the sump.)
For what its worth, only one of these companies-AeroShell Care-markets via e-commerce. Point, click and ship; three days later, the $14.95 kit arrives in your mailbox. Quite convenient.
Hey, don’t Fly That Thing!
Out went the samples on October 17th and on October 24th, the phone rang. Rex Havis of Spectro was calling to say there was a real problem with our oil samples and that we shouldnt fly until we talked.
Returning the call, we learned that Havis wanted more information and another sample before interpreting the results. The first sample-genuine Phillips XC aviation oil-was normal, although the silicon was a little high. (Could it be we got a little fast and loose with the Dow DC-4 around the filter gasket?)
But the second sample-straight from the Nissan sump-was an eyebrow raiser. By Spectros estimation, the iron had spiked from 20 PPM to 65 PPM and the aluminum increased from 3 PPM to 28 PPM in a mere 36 hours of engine operation.
I don’t know whats going on there but until we get a better handle on what weve got, I would recommend not flying the airplane, Havis said.
We hadnt yet mustered the courage to ask if it was okay to drive the truck to the airport for another sample. When we finally fessed up, Havis didnt miss a beat: If you give me the mileage on that truck sample, Ill go ahead and give you a report on that, too.
Summing up: Spectros Havis was Johnny on the spot with a quick analysis and a timely phone call. Even though he didnt spot the automotive oil, he caught on to our bait-and-switch trick after a fashion and he wasted no time waving a warning flag. Good show, in our estimation.
Aviation Oil Analysis
Next to arrive-via first class mail eight days after the sample was sent-was a report from Aviation Oil Analysis in Phoenix. Not bad turn around time but we think the report should have been faxed.
As Spectro had, AOA uncovered a huge leap in iron-from 23 to 194 PPM in the truck sample. Aluminum had tripled from 7 to 24 PPM and silicon was high in both samples, doubling in the second one.
Curiously, none of this alarmed AOA enough to call or fax the results and other than recommending checking the filter for chips and resampling, it had no other comments. AOA uses a series of codes to indicate various kinds of potential wear and troublespots. AOA did not, however, suggest checking the air filter or induction system for leaks, a common strategy when silicon is high, since silicon is essentially dirt.
On the plus side, we liked AOAs crisp report format, which uses plain language rather than the more obscure chemical symbols.
When we asked the lab analyst, Sam Villegas, why we hadnt been notified, he explained that according to AOAs data, the iron aluminum spikes were within normal limits for an IO-360. Had they been higher, a fax or phone call would have been forthcoming.
Aviation Laboratories
Eleven days after the samples were sent out, we received a written analysis from Aviation Laboratories, of Kenner, Louisiana. This lab markets under the trade name Metal Check and is found in the Sportys catalog and also through AOPA. As noted, Sportys charges a premium ($22.95) while AOPA sells the same kit for $14.
Sportys catalog claims the reports are sent out within 24 hours of the analysis and this appears to be the case, or close. The report is dated October 23rd, with an October 25th postmark. If the analysis was done late in the day, we have no complaints about the extra day.
Aviation Laboratories has somewhat of a history with our Mooney, since the shop that did our annual has sent a couple of samples their way. Accordingly, our report came back with the previous analysis (January 2000) plus the two new samples we sent.
Results: The genuine Phillips XC tested within normal limits, with no flag on the high silicon, which had doubled from the previous report, something that caught the eye of the other labs.
Our bogus truck sample was loaded with iron and aluminum, according to Aviation Labs, and the silicon was eight times higher than in the January report.
The lab attached this comment: !!!!CAUTION!!!! Contact engine manufacturers service rep. Resample in 25 hours. Why no phone call or fax, which the lab says it provides? Chris Allen, the lab manager, told us a fax should have been sent but apparently wasnt because both samples arrived at the lab on the same day and even though the truck sample had a later sampling date, someone assumed we had already been notified about the high metal levels.
We view this as adequate but not exceptional service. Frankly, we would have preferred a phone call, such as Spectro provides, and for a premium-priced service-which this is-passing the buck to a Lycoming service rep is somewhat of a disappointment. Other labs seem to offer more information and advice.
Engine Oil Analysis
Any chance you could leave me out of this? asked Howard Fenton, of Engine Oil Analysis, when we called 13 days after the samples were sent to query the whereabouts of the report. Fentons EOA has been our regular lab for five years and has always returned reports by fax within three to five days.
As bad luck would have it, however, his spectrometer broke just as the iron-rich truck sample was being burned. It was just going back into service when we called. I just didnt believe these results, Fenton said, its sitting here on my desk with a note possible malicious contamination. (Speaking of malicious, we let Fenton explain all this before letting him in on our cheap trick.)
Like the other labs, Fenton had found the high iron and aluminum but wanted another burn to confirm it before calling with the bad news.
I wasnt about to call back until I had it locked down. It looked to me like a good possibility of camshaft failure, Fenton said. He conceded that unless the lab tech was looking, the likelihood of noticing that it was automotive oil is nil.
The legitimate aviation oil sample tested within expected limits, Fenton reported. Having dealt with EOA for years on several engines, were willing to give this lab the benefit of the doubt on out-of-limits notification.
The fact that Fenton faxes all reports to owners and phones on abnormal results is a plus. According to our records, turn around time has been three to five days.
Fenton also provides running commentary on his reports, suggesting what trouble may be lurking in the wear metal numbers. He frequently phones customers to fill in blanks in the analytical picture.
Analysts, Inc.
Analysts, Inc. operates under an arrangement with Shell to provide oil analysis services for aircraft owners, both piston and turbine. Its the only company which markets kits via e-commerce www.aeroshell.com/av_Products/av_products.html) and is thus convenient to use.
According to the Web site, the $14.95 basic kit includes wear metal tests, plus fuel dilution, viscosity and moisture content, with normal results mailed and critical condition reports faxed or phoned, along with recommendations, with turn around time in 24 to 48 hours.
Would the lab keep this promise? Our spiked truck oil sample would give them a chance. Sure enough, 13 days after the sample was mailed, an Analysts, Inc. representative called to say we appeared to be running our Lyc on auto oil and that it was somewhat diluted with lead-free gasoline. Further, the sample seemed to indicate some cylinder wear that we might want to look into.
Not bad. However, a spokesman for the lab said it missed its promised turn around time by nearly a week because the lab was behind. Inexplicably, the samples-mailed individually by Priority Mail-took a week to reach the lab and another five days for analysis, a worrisome delay if you think your engine is about to tank.
If that delay is an anomaly, so be it. If we can give Fenton a break, Analysts deserves one, too. However, what we found off-putting about this lab is the difficulty we had in tracking down the delayed samples.
The Web site has no phone contact numbers and we played phone tag with three baffled offices before tracking the samples whereabouts to Analysts Atlanta lab. Later that afternoon, we got the phone call but no fax, since the analytical form doesnt provide a space for it nor a phone contact for questions. We were able to contact all of the other labs directly, reaching the person doing the analysis in minutes.
Conclusion
Obviously, all of these labs offer comparable services at prices within a couple of bucks of $14, the exception being Aviation Labs Sportys-marketed kit for $22.95. Sportys, of course, offers excellent customer service and convenience and if thats worth twice the price, be our guest. Otherwise, all of the other sources are just as convenient to buy from at half the price.
As lab services go, we were most impressed with Spectro and Fentons Engine Oil Analysis, the broken spectrometer notwithstanding. Our follow-up calls to these labs yielded extensive and knowledgeable discussions that the other labs didnt seem to offer. We like the fact that Shells Analysts, Inc. picked up the auto oil ruse. We wish they were easier to contact to chase this stuff down. When you have questions about a sample report, you want answers. (And hey, Shell says theyve got answers.)
We were disappointed that Aviation Laboratories and Aviation Oil Analysis didnt fax or phone with warnings of high metal content. In light of Spectros urgent call, we disagree with AOAs conclusion that the metal wear limits were within normal ranges on the second sample. We would like a call or a fax on that and we’ll take if from there, thanks.
Further, Havis and Fenton both offer suggestions on where the metal is coming from, not just the bland comment that aluminum appears high or ubiquitous check filter for chips, resample in 25 hours.
Given the similar pricing, we think the labs that phone to talk about these issues offer the better deal, so Spectro and Engine Oil Analysis get our vote as the top-value labs, with Analysts, Inc. worth an honorable mention.
Also With This Article
Click here to view the oil analysis checklist.
Click here to view the lab comparison.
Click here to view “The Magic in the Numbers.”
-by Paul Bertorelli
