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IO-540 Engine Options

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kirkbauer

Well Known Member
I'm debating between a normal IO-540, a Thunderbolt IO-540, or a third-party engine source. I did a lot of searching here on VAF but my ignorance of engines is not helping me out. I'm hoping some people can help me interpret some of the options on the Van's Thunderbolt order page (https://www.vansaircraft.com/order-a-kit/lycoming-thunderbolt-engines-order-form/). I'm looking for dual pMags but am not looking to complicate my build or require significant alterations.

1) It looks like if I order this engine I get an Airflow Performance fuel system -- do I want that? What does the normal IO-540 come with? How do both of these compare to Silverhawk? They have a note on the order page
  • Note: When ordering the IO-540 with an Airflow Performance throttle body, you will need to provide some components that are not included in our Firewall-Forward kit. Specifically, the push-pull cables, VA-182 throttle/mixture bracket and fuel hoses will likely need to be replaced with parts that fit the AFP option, and the Van's filtered air box may require some modification .
2) The order page says "requires Slick-Start booster system". What does that mean and why don't I need it for the normal IO-540?

3) I read that the Cold Air Induction option requires cowling modifications. How much power do I gain from this expensive ($5,700) upgrade and how extensive are the modifications required?
 
If your top priorities are “not looking to complicate my build or require significant alterations”, then you need to weigh the Cold Air Sump option.

Modifying the stock Van’s cowl is possible, but not for the faint of heart. Two vendors offer RV-10 cowls for the Cold Air Sump IO-540, Showplanes and James Aircraft. I have the James version in the hangar (along with a new Thunderbolt Cold Air Sump IO-540). The tumbrule is this is a ~15hp bump over the vertical induction IO-540.

Some other thoughts:
- Compression ratio. Thunderbolt offers 9.0 pistons if you want (I think this is a~$3K up charge but you should check). I stayed with stock 8.5 pistons as I want the option to burn 93 ethanal free mogas - but many people opt for 9.0 pistons.
- The first build was a stock vertical induction Lycoming IO-540 with Slick Mags (no Slick start booster). The six cylinder pMag was not yet available. I was careful to only start on the left mag as it had a timing retard breaker. Never a problem starting.
- The new engine will have dual pMags (so the Slick booster is not applicable as the pMags have retarded timing during start). I’ve been running dual pMags on all the other builds.
- I consider the AFP option a no brainer and recommend it. The needed control cable brackets are available from Don at AFP (and just bolt on).
- I suspect most third party engine builders can offer the same options as Thunderbolt, so shop around.

Carl
 
If you are a hands on person, I would recommend Aerosport. I got my IO375 from them, dual pmags, inverted oil, but best of all, I got to travel there and build it myself with their oversight. Fantastic experience and I know my engine inside and out, literally.
 
The stock IO-540 has a bothersome AD to check impulse coupled Slick mags every (IIRC) 250 hours. In 2010 the standard IO-540 came with one retard mag, no impulse mag. The retard mag will start the engine as long as plug gaps are not too large and your starter motor turns fast enough. With the Slick start it always starts - as long as your battery works.
 
As part of your decision making, be sure to ask about delivery times. As I understand it, the Thunderbolt engines back log is about 2-3 years. So if you are wanting an engine in just a year or so, you will likely want to go with the standard Lycoming YIO-540.

An impulse mag is not recommended for the IO-540, so they come standard with a retard mag, and a recommendation for adding a slick start unit. This is a small box that mounts on the fire wall and increases the spark voltage during starting. I don't think Lycoming offers P-mags unless you buy through their Thunderbolt division, at least they didn't used to offer them, but perhaps that has changed.

If you go with a 3rd party, they will find a used engine case, and replace all the internals and cylinders to build you a "new" engine. Some of these companies have a great reputation, but if you are concerned with resale, they might not hold their value quite as well as a factory manufactured engine direct for Lycoming.

Cheers,
 
Thanks for the feedback, everybody. I am considering Aerosport Power in Canada to build my own engine and that's part of the reason for this post. I'm about 2 years out from needing an engine so I'm trying to get on the schedule now if I want to go that direction. Some takeaways so far:

1) I don't think I'll do the cold air sump option since I don't want to have to modify my cowl.
2) I'll be using dual pMags so the slick start is not relevant to me.
3) I plan to stick with 8.5 compression to enhance fuel compatibility

Some additional questions:

1) If I go with Aerosport Power, I believe that is a brand new engine, correct? Are there any import taxes I need to worry about?
2) I haven't asked if it can be changed yet, but Aerosport mentioned a Sky-Tec Lightweight Starter and a Precision Silverhawk fuel injector. Am I going to regret either of these items when compared with (for example) the Airflow Performance injection system?
 
kirkbauer said:
Thanks for the feedback, everybody. I am considering Aerosport Power in Canada to build my own engine and that's part of the reason for this post. I'm about 2 years out from needing an engine so I'm trying to get on the schedule now if I want to go that direction. Some takeaways so far:

1) I don't think I'll do the cold air sump option since I don't want to have to modify my cowl.
2) I'll be using dual pMags so the slick start is not relevant to me.
3) I plan to stick with 8.5 compression to enhance fuel compatibility

Some additional questions:

1) If I go with Aerosport Power, I believe that is a brand new engine, correct? Are there any import taxes I need to worry about?
2) I haven't asked if it can be changed yet, but Aerosport mentioned a Sky-Tec Lightweight Starter and a Precision Silverhawk fuel injector. Am I going to regret either of these items when compared with (for example) the Airflow Performance injection system?
Click to expand...
Mattituck built my IO-540 with Silverhawk injector, sky-tec lightweight starter, 9:1 pistons and dual mags that I subsequently replaced left impulse with a sure-fly. Amazing engine, smooth as all get out. Have had no problem with starter or injection system. Wish they were still in business.

Phil
KBTF
Salt Lake City
RV-10 built/flying
Murphy Moose- building
 
kirkbauer said:
Thanks for the feedback, everybody. I am considering Aerosport Power in Canada to build my own engine and that's part of the reason for this post. I'm about 2 years out from needing an engine so I'm trying to get on the schedule now if I want to go that direction. Some takeaways so far:

1) I don't think I'll do the cold air sump option since I don't want to have to modify my cowl.
2) I'll be using dual pMags so the slick start is not relevant to me.
3) I plan to stick with 8.5 compression to enhance fuel compatibility

Some additional questions:

1) If I go with Aerosport Power, I believe that is a brand new engine, correct? Are there any import taxes I need to worry about?
2) I haven't asked if it can be changed yet, but Aerosport mentioned a Sky-Tec Lightweight Starter and a Precision Silverhawk fuel injector. Am I going to regret either of these items when compared with (for example) the Airflow Performance injection system?
Click to expand...
I haven't spun mine yet, but i used Darren Jones at Aerosport Power and was happy with the service. It took FOREVER it seemed but i ordered in 2021 (lots of supply chain issues) and got it in 24. Darren will PATIENTLY walk you through the options so don't worry about what you don't know.
 
kirkbauer said:
Thanks for the feedback, everybody. I am considering Aerosport Power in Canada to build my own engine and that's part of the reason for this post. I'm about 2 years out from needing an engine so I'm trying to get on the schedule now if I want to go that direction. Some takeaways so far:

1) I don't think I'll do the cold air sump option since I don't want to have to modify my cowl.
2) I'll be using dual pMags so the slick start is not relevant to me.
3) I plan to stick with 8.5 compression to enhance fuel compatibility

Some additional questions:

1) If I go with Aerosport Power, I believe that is a brand new engine, correct? Are there any import taxes I need to worry about?
2) I haven't asked if it can be changed yet, but Aerosport mentioned a Sky-Tec Lightweight Starter and a Precision Silverhawk fuel injector. Am I going to regret either of these items when compared with (for example) the Airflow Performance injection system?
Click to expand...
Unless they buy factory new parts from lycoming more than likely it is an overhauled or remanufactured engine. Factory new engine with all new first run metal only comes from lycoming as far as I’m tracking.
 
kirkbauer said:
2) I haven't asked if it can be changed yet, but Aerosport mentioned a Sky-Tec Lightweight Starter and a Precision Silverhawk fuel injector. Am I going to regret either of these items when compared with (for example) the Airflow Performance injection system?
Click to expand...

I would advise against a Sky-Tec LW starter Sky-Tec NL or B&C better.
 
Majorpayne317641 said:
Unless they buy factory new parts from lycoming more than likely it is an overhauled or remanufactured engine. Factory new engine with all new first run metal only comes from lycoming as far as I’m tracking.
Click to expand...
I recently built my IO-540-D4A5 with Aero Sport Power. All parts were factory-new except for the oil sump (Aero Sport has been unable to get new sumps from Lycoming). It was my choice as to whether I wanted to wait for a new sump or proceed with a used one.

Per the other comment above, my starter is a Sky-Tec 149-NL (which is what Aero Sport recommended for this engine).

Details on my build log for anyone curious about the build school option: https://airplane.allanglen.com/2024/07/11/engine-build/

1723213983762.png1723214054401.png1723214032193.png
 
allanglen said:
I recently built my IO-540-D4A5 with Aero Sport Power. All parts were factory-new except for the oil sump (Aero Sport has been unable to get new sumps from Lycoming). It was my choice as to whether I wanted to wait for a new sump or proceed with a used one.

Per the other comment above, my starter is a Sky-Tec 149-NL (which is what Aero Sport recommended for this engine).

Details on my build log for anyone curious about the build school option: https://airplane.allanglen.com/2024/07/11/engine-build/

View attachment 68040View attachment 68042View attachment 68041
Click to expand...
Awesome Build report. Curious - is that a cold air sump and who ended up supplying it?
 
allanglen said:
I recently built my IO-540-D4A5 with Aero Sport Power. All parts were factory-new except for the oil sump (Aero Sport has been unable to get new sumps from Lycoming). It was my choice as to whether I wanted to wait for a new sump or proceed with a used one.

Per the other comment above, my starter is a Sky-Tec 149-NL (which is what Aero Sport recommended for this engine).

Details on my build log for anyone curious about the build school option: https://airplane.allanglen.com/2024/07/11/engine-build/

View attachment 68040View attachment 68042View attachment 68041
Click to expand...

Your build log is fantastic👍🏻
 
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