Conquered a major milestone this summer. Van’s specifies an engine for the RV-10 in the Lycoming parallel valve six cylinder O-540 (carbureted) or IO-540 (injected) series developing between 235 and 260 hp.
The cowling and firewall forward kit are all designed around the power to weight ratio, dimensions, vertical induction style etc of this segment of the 540 powerplant line, which can go up to a whopping 380 hp with angle valves, different cranks, lots more weight, turbos and what not.
Vans also built a prototype RV-10 using the six cylinder 210hp Continental IO-360 but never productized the FWF/cowling due to poor customer feedback and presumably low demand. Nonetheless, the prototype powered by this engine, N220RV, demonstrated still excellent performance and is used to this day for demo flights and transition training.
For finding and procuring a suitable engine, today a builder like me has a small list of possible options/price points due to a narrowing of the supply chain for the suitable 540 series. Demand rose sharply in the last decade or so due in part to the RV-10 and numerous other homebuilt designs like the Bearhawk that call upon this class of 540s. Now the options I had were:
- Lycoming factory new experimental IO-540-D4A5 260hp through Van’s who now gets a preferred OEM price from Lycoming that they can partially pass through to the builder – $47,700 USD as of June 2017
- Engine shops that offer overhauls/new builds with a focus on the experimental category like Aerosport Power (in my home province BC!), Barret Precision Engines, Titan etc. – High 30’s to mid 40s to higher depending on core source / options
- Mid time used 540 via Wentworth, Barnstormers, Ebay etc – Huge savings to huge risk possible, requiring careful research.
I spent quite literally weeks determined to get this set up for my build once and for all. Having not ruled out the new buy via Van’s, I set out to look into options 2 and 3 and see what I could find.
I can’t say enough good things about Aerosport Power and in particular one of their master engine builders Darren Jones who invested considerable time advising me with no expectations of a purchase or pressure of any kind. Simply world class help. I quickly learned that some years back shops like Aerosport were able to build up factory new IO-540s using OEM parts from Lycoming and stay highly competitive vs the full package direct from the factory via Van’s. For whatever reason though, Lycoming raised the parts prices to these different channels to the point where they could no longer compete with Van’s OEM prices. What they are able to do effectively now is source a good core, meaning a serviceable used crankshaft and case, and build what is effectively a re-manufactured “new” engine with all new parts aside from case and crank. It seemed like I could get this through in the high 30s all in. So I parked that avenue as the leading candidate while I checked out option 3.
Option 3 was fraught with needing a high research and time investment from me and again I got tons of helpful advice from Darren at Aerosport. It took me quite a while to figure out which of the seemingly dozens of 540 variants could be compatible. I highly recommend downloading the Lycoming special service publication SSP-110-1 (https://www.lycoming.com/sites/default/files/SSP-110-1%20Certificated%20Engines.pdf) which allows you to trace what the differences between the different models are. I supplemented this with their IO-540 Operator’s Manual, overhaul manual and illustrated parts catalogs to figure out what is what. This was a grueling amount of research but worth it in the long run and I now know my engine parts inside and out.
One by one, I then got pics and logs from several ads that showed up on ebay and barnstormers and from some of the salvage guys like Wentworth about opportunities available. A few got sold, a few I ruled out because of something I didn’t like in the logs (think carefully about prop strikes and other damage, as well as the number of overhauls which in each instance machine the crank and case to reduced but still serviceable dimensions that limit how many overhauls you may be able to achieve in the future). And so it went, until within a couple of weeks I found the winner!
I found an ad on barnstormers for a 1,055 TTSN, built new in 2002, first run (meaning not overhauled once yet), clean logs, clean pics, no damage history IO-540-AB1A5. It was being listed by a gentleman and pilot named Bill in Texas who had recently removed it from his Cessna 182T in order to replace with a higher power STC engine package available for his 182. Now the -AB1A5 is a bit of an odd duck recent variant from Lycoming. When Cessna restarted new production of the 182 in the late 90s, they switched over from Continental to Lycoming who by then was a sister company under their Textron corp ownership. They moved away from carbureted to fuel injected at the same time in order to once and for all do away with carb heat requirements in the 172s and 182s. The 182 for decades to that point had been powered by a Continental O-470 producing 230 hp. So to match this power output with the 540, seems as though Cessna and Lycoming tweaked the 540 series to reduce weight a little and limit peak RPM to 2,400 but still produce exactly 230 peak hp. It’s parallel valve, 8.5:1 compression, 382 lbs dry weight, vertical induction. Van’s IO-540-D4A5 they sell fro the RV-10 is parallel valve, 8.5:1 compression, 412 lbs dry weight, vertical induction.
Bingo! I concluded that this powerplant would be a great match for my RV-10 and deliver to me the added benefit of lower peak rpm for cabin noise and vibration. It’s only 5hp below the various 235hp models Van’s says is a-ok and still 25hp more than their 210hp prototype which performs well.
I’ve interpolated Van’s stated performance figures below to derive anticipated 230hp performance. Looks great!
Stay tuned to my next post for an outline of how I plan to preserve & corrosion protect the engine for a couple of years while I continue to work on the airframe build.


