By Vic Syracuse, EAA Lifetime 180848
This piece originally ran in Vic’s Checkpoints column in the April 2024 issue of EAA Sport Aviation magazine.
As I write this column, I am recovering from another miserable bout with COVID. I’m sure I’m not the only one who had the 2023 holiday season ruined by it. Even though my body was down and out, it seems my mind is always churning about something. For some reason or another, it seems to spend more cycles on aviation than anything else. I’m probably not the only one here with that problem.
I ended up thinking about how much I use the RV-10 during the year, the average being 200-250 hours over the last five to six years. In those hours are some rather long trips, such as Alaska, and sometimes three-hour one-way trips in the Lower 48. I use it weekly for designated airworthiness representative work and prebuys. I need it to be reliable, and I certainly don’t want to get stuck anywhere.
The airframe now has about 2,600 hours on it and the engine has about 1,100 hours on it, so I started thinking about bigger picture items that may need some attention. Sure, I do all the routine stuff that I’m sure most of you do, such as regular oil changes, spark plug cleaning and gapping, air filter cleaning/replacement, and tire/brake maintenance. Plus, there are 500-hour inspections for items such as magnetos, spark plug wires, and exhaust valve guides, which by now I have done multiple times on this engine.
When I think of reliability, I divide the aircraft into three buckets: airframe, engine, and electrical. It forces me to think about single points of failure relative to each bucket and whether there is a high probability of failure, and if it needs immediate attention, or perhaps just increasing the frequency of the maintenance as time progresses would suffice.
Being sick for 10 days gave me a lot of time to think about these things as well as taking my mind away from the misery of not feeling well. I did come up with a plan, and I am going to share it with you over the next few columns as it is not just a simple “take a look” kind of solution, at least for the actions I have in mind.
Let’s start with the engine. Since the RV-10 is a single-engine aircraft, reliability of the engine is especially important. I’ve made an argument in the past that replacing an engine at midtime has a lot of benefits. A midtime engine is much more valuable for resale than one that has reached TBO. It also allows you to schedule the downtime and perhaps better accommodate the financial hit of a new engine.
Sometimes it can eliminate the death by a thousand cuts on engines that intermittently wear out items at different rates prior to reaching time between overhauls (TBO), such as cylinders, fuel pumps, carburetors/fuel servos, etc. I did exactly that with my first engine in this RV-10, replacing it with a new Lycoming Thunderbolt engine at 1,000 hours.
This Thunderbolt engine has now passed the 1,100-hour mark, so I find myself asking the same question, and I am thinking a little differently this time around for several reasons. First, as you may know, the Thunderbolt engine is custom-built and handmade at the Lycoming factory.
I think it is made as carefully and perfectly as an engine can be. I visited the factory as they were building it, and it was impressive. In those 1,100 hours, it has never missed a beat and has taken us to Alaska and back many times. I’ve always changed the oil at 35-hour intervals, and it currently burns 3 quarts of oil between oil changes. That’s really great for an IO-540.
I just checked the compressions this week, and on a cold engine that hadn’t been run for two weeks, three of the cylinders were at 80/80, and the other three were at 78/80. The oil screen and filter are always clean and free of debris. I’m thinking I shouldn’t mess with something that is in such great shape.
Currently, some other factors in the market are telling me I should just keep running this engine. First, the prices on the new engines are astronomically high, more than 50 percent higher than when I purchased this one six years ago.
Then there is the timing factor, as it would probably be 18 months or more before I could get one. So, it’s kind of a moot point to do anything with it right now, as it certainly doesn’t need to be pulled for an overhaul. I’m also thinking that since it is a Thunderbolt engine, it might just make sense to run this one all the way to TBO and then have it overhauled when I can schedule it since everything inside it was new at assembly. For now, I am leaning toward that scenario.
My next line of thinking around the engine for reliability is to focus on the external systems that are attached to it and could adversely affect reliability, such as the ignition systems, fuel systems, starter, and air system. Let’s start with the ignition systems.
I have both an electronic ignition and a magneto on my aircraft. One of each has always been my first choice. Having been in technology my whole life, I like to have a backup system that is from a different vendor. While I’ve never had an electrical failure on any of the aircraft I’ve built, I still like the idea of being able to turn off the master switch if there is smoke in the cockpit knowing the engine will keep running while I sort it out.
Yes, I know arguments can be made for dual electronic ignition systems, and some are even approved now for certified aircraft. I also know and have experienced the dark side of my mind wandering when I am over the Gulf of Alaska picking up ice and hoping all of those electrons just keep doing what they are supposed to, so I don’t have to go swimming in the ice-cold water below.
Both ignition systems have some maintenance requirements. Starting with the Light Speed Engineering Plasma III, there are regular tasks such as cleaning, gapping, or replacing the spark plugs. The Light Speed uses Denso automotive plugs, and I check them every 50 hours when I am cleaning and gapping the aviation plugs used on the magneto.
I replace them every 100 hours, as it is cheap insurance. I have found the older-style coils for the Light Speed sometimes failed and could usually be diagnosed by checking for about 8,000-9,000 ohms of resistance across the spark plug terminals. On the failed coils the resistance would either be zero or much higher than 9,000 ohms. For the last year, I have been running a newer-style coil, which is a little bigger than the original coils, and they seem more reliable. For the long trips such as to Alaska, I carry a couple of spare coils, just in case.
Another maintenance item on the Light Speed ignition system is the recommendation that the spark plug wires be replaced every 10 years or 500 hours. So, it’s time to do that again. You can purchase the new wires from Light Speed Engineering, but I find it is just as easy to make them myself, so that’s what I do. See the pictures for some details.
The magneto also has some maintenance requirements. The plugs need to be cleaned and gapped about every 50 hours, and I usually replace the massive electrode aviation plugs at around 400-500 hours. I have found the Tempest UREM40E to be the best cost-effective plug for the IO-540 if using a massive electrode. The premium platinum fine wire Tempest UREM38S are nice, don’t require cleaning as often, and seem to be less prone to lead fouling.
The Slick magnetos have a 500-hour inspection requirement. You can do it yourself if you are comfortable taking apart a magneto, but most builders aren’t. So, you need to remove it and send it off to an inspection facility or have your local A&P mechanic do it. I usually do mine around 450 hours. (Why tempt fate?) The problem right now for the six-cylinder magnetos is that all of the parts to do the inspection are becoming harder to get and ridiculously more expensive.
The cost of doing it yourself is almost the same as installing an overhauled magneto you can get from Aircraft Spruce or one of the other vendors. Having done the 500-hour inspection on mine twice now and replacing all the internal parts, I decided to replace the magneto, but also to go ahead and “supersize” it. Next month I’ll tell you all about that decision, and I’ll continue with the other aspects of reliability maintenance.
In the meantime, I survived COVID, again. And I have already done a prebuy and licensed a new Kitfox for a builder this week, so my fun factor is alive and well. I hope all of you are off to a great start in the new year!
Vic Syracuse, EAA Lifetime 180848, is a commercial pilot, A&P/IA mechanic, designated airworthiness representative, and EAA flight advisor and technical counselor. He has built 11 aircraft and has logged more than 10,000 hours in 74 different types. Vic founded Base Leg Aviation, has authored books on maintenance and prebuy inspections, and posts videos weekly on his YouTube channel. He also volunteers as a Young Eagles pilot.